Patent Application
20170082603
This invention relates to an improved diagnosis method of liver fibrosis or cirrhosis, through combination of at least one blood test or its constitutive markers and at least one physical method for diagnosing liver fibrosis, in an individual, especially in an individual suffering from a condition involving significant or severe fibrosis or cirrhosis. The method of the invention leads to scores called SF or C-index and optionally to combination thereof.
Liver biopsy is the historical means in order to diagnose liver disease in patients. However, since liver biopsy is invasive and expensive, non-invasive diagnosis of liver fibrosis has gained considerable attention over the last 10 years as an alternative to liver biopsy. The first generation of simple blood fibrosis tests combined common indirect blood markers into a simple ratio, like APRI (5) or more recently FIB-4 (6). The second generation of calculated tests combined indirect and/or direct fibrosis markers by logistic regression, like Fibrotest (7), ELF score (8), FibroMeter (9), Fibrospect (10), and Hepascore (11). For example, WO03073822 describes a non-invasive method for the diagnosis of liver disease and its severity, by measuring levels of specific variables, including biological variables and clinical variables, and combining said variables into mathematical functions to provide a score, often called “score of fibrosis”. The method of WO03073822 is also useful for monitoring the efficacy of a treatment of a liver disease or condition.
A further non-invasive diagnosis method of liver fibrosis is to use physical methods, for example ultrasonographic elastometry (12) in order to collect data useful for the diagnostic of fibrosis, such as for example “Liver Stiffness Evaluation” (LSE). In a recent article entitled “Performance of Transient Elastography for the Staging of Liver Fibrosis: A Meta Analysis” released in Gastroenterology 2008; 134:960-974 Friedrich-Rust et al validated “Transient Elastometry” for the staging of Liver Fibrosis.
Finally, blood fibrosis tests have been combined into sequential algorithms in order to increase the diagnostic accuracy and limit the rate of liver biopsy (13-16). These sequential algorithms are usually based on a stepwise diagnosis including blood tests as a first step, followed by liver biopsy for the remaining grey zone of indeterminate cases. However, clinical applicability of these multiple-step sequential algorithms is difficult. Moreover, liver biopsy is still required in 20 to 50% of patients.
The diagnostic target of the present invention can be:
One skilled in the art addressing such diagnostic technical issues, knows that the identification of reliable methods for early and accurate diagnosis of liver fibrosis is an on-going process, and that there is an important medical need for continuing to improve the diagnosis of liver fibrosis and to improve the monitoring of the treatment of a liver disease or condition. Moreover, due to price and invasiveness of biopsy, there is still a need to reduce liver biopsy requirement. The diagnostic methods are appreciated by their performance, i.e. their ability to correctly classify the tested individuals, as to their fibrosis development.
Up to now, one skilled in the art used to implement blood tests combining blood markers and clinical markers such as age, sex, etc. . . . on the one hand, and imagery means on the other hand. Both blood test and imaging means were deemed as having their own specific advantages and one skilled in the art used blood tests or imaging means, depending on the Metavir stage of the patient.
The Applicant surprisingly realized that combining scores from blood tests or markers from blood tests and data issued from imaging means, resulted in a score having an incredibly high diagnostic performance (accuracy). When performing the present invention, the Applicant compared for the first time the diagnostic accuracy of imaging data, such as for example liver stiffness evaluation, and 5 blood tests, and compared their accuracy to the accuracy of their synchronous combination, either in a large population of patients with various causes of liver diseases or conditions (see example 2) or in an homogeneous population in terms of cause, such as for example patients suffering from chronic hepatitis C (see example 1).
At the time where the Applicant conceived the invention, one skilled in the art had no information whether or not the combination of scores issued from blood tests or markers from blood tests and of data issued from imaging means was of interest. The statistical evaluation, e.g. trough differences between the AUROCs (Area Under the Receiver Operating Characteristic), i.e. the main diagnostic information ever used combining sensitivity and specificity, of this combination had not been performed yet at the date of invention.
As an example of data of interest issued from imaging means, is the Liver Stiffness Evaluation (LSE). LSE was known for having a good accuracy for the diagnosis of cirrhosis but reproducibility of LSE was poor in early fibrosis stages. For this reason, LSE was mainly used for the diagnostic of cirrhosis.
For early fibrosis stages, blood tests have shown higher reproducibility and accuracy than LSE.
Surprisingly, the Applicant has found that the combination of diagnostic information from blood tests or their constitutive markers and data from imaging means, especially but not exclusively Fibroscan™ (also known as Vibration-Controlled Transient Elastography or VCTE) or ARFI data, such as for example LSE data, provided several advantages and unexpected accurate results for the diagnosis of liver fibrosis, from significant fibrosis to severe fibrosis and cirrhosis.
The Applicant has also set up a first algorithm, called Angers SF-algorithm, combining scores from blood test and imaging data, preferably Fibroscan data, appeared to be, at the date of priority of the present application, the best solution among known alternatives to the Applicant, such as high correct classification and low liver biopsy requirement, reflected by a low liver biopsy/accuracy ratio.
The present invention thus relates to a non-invasive method leading to a score obtained by a mathematical function, such as for example a binary logistic regression, combining blood test score and imaging, preferably Fibroscan (also known as Vibration-Controlled Transient Elastography or VCTE), data for assessing, with a high accuracy, the presence or the severity of fibrosis in an individual.
The present invention also relates to a non-invasive method leading to a score obtained by a mathematical function, such as for example a binary logistic regression, combining the markers from blood tests and imaging data, preferably Fibroscan (also known as Vibration-Controlled Transient Elastography or VCTE), for assessing, with a high accuracy, the presence or the severity of fibrosis in an individual.
The synchronous combination set forth in the invention results in the accumulation of blood tests and imaging means advantages, in the subtraction of their drawbacks, thereby significantly increasing the single diagnostic accuracy for liver fibrosis.
In an embodiment, the method of the invention includes repeating several times, at least twice, the method, in order to obtain at least two scores. In this embodiment, the method of the invention may also include, in a further step, the combination of at least two scores as described hereabove (i.e. two scores obtained by a mathematical function, such as for example a binary logistic regression, combining blood test score and imaging data, preferably Fibroscan data), said combination being implemented in an algorithm based On the diagnostic reliable intervals (see for example table 5 of example 1). Carrying out this further step leads to three new scores/classifications called F≧2 index, F≧3 index, F4 index) for the non-invasive diagnosis of fibrosis. Implementing this further step is of high industrial interest, and results in extended accuracy. Thus, the invention also relates to a method wherein the combination through a mathematical function, of at least one blood test and of at least one data issued from a physical method of diagnosing liver fibrosis, is performed at least twice and the at least two resulting scores are combined in an algorithm based on the diagnostic reliable intervals.
The method of the invention improves the diagnostic accuracy and markedly reduces the biopsy requirement in algorithms.
This invention therefore relates to a method of diagnosing the presence and/or severity of a liver pathology and/or of monitoring the effectiveness of a curative treatment against a liver pathology in an individual, comprising the combination, of at least one blood test and at least one data issued from a physical method of diagnosing liver fibrosis selected from the group consisting of medical imaging data, including ultrasonographic elastometry (like Fibroscan™ also known as Vibration-Controlled Transient Elastography or VCTE or ARFI) data, and clinical measurements said combination being performed through a mathematical function. According to a first embodiment, the medical imaging data are LSE data. According to another embodiment, the clinical measurements, are measurements of spleen, especially length, as known by one skilled in the art to be interesting data for diagnosing fibrosis.
The mathematical function is known to one skilled in the art. The mathematical function preferably is a binary logistic regression.
More specifically, the method of the invention includes:
In one embodiment, the FibroMeter is a blood test based on alpha-2 macroglobulin (A2M), hyaluronic acid or hyaluronate (HA), prothrombin index (PI), platelets (PLT), aspartate aminotransferase (AST), urea, gamma-glutamyl transpeptidase (GGT), bilirubin (bili), alanine aminotransferase (ALT), ferritin (fer), glucose (glu), age, and sex.
In another embodiment, the FibroMeter is a blood test based on alpha-2 macroglobulin (A2M), hyaluronic acid or hyaluronate (HA), prothrombin index (PI), platelets (PLT), aspartate aminotransferase (AST), urea, gamma-glutamyl transpeptidase (GGT), alanine aminotransferase (ALT), ferritin (fer), glucose (glu), age, sex and weight.
In another embodiment, the FibroMeter is a blood test based on alpha-2 macroglobulin (A2M), hyaluronic acid or hyaluronate (HA), prothrombin index (PI), platelets (PLT), aspartate aminotransferase (AST), urea, gamma-glutamyl transpeptidase (GGT), bilirubin (bili), alanine aminotransferase (ALT), ferritin (fer), glucose (glu), age, sex and weight.
In one embodiment, the cause of chronic liver disease is viral and the FibroMeter is based on alpha-2 macroglobulin, hyaluronic acid (or hyaluronate), prothrombin index, platelets, aspartate aminotransferase (AST), urea, age and sex. In another embodiment, the cause of chronic liver disease is viral and the FibroMeter is based on alpha-2 macroglobulin, hyaluronic acid (or hyaluronate), prothrombin index, platelets, aspartate aminotransferase (AST), urea and age. In yet another embodiment, the cause of chronic liver disease is viral and the FibroMeter is based on alpha-2 macroglobulin, prothrombin index, platelets, aspartate aminotransferase (AST), urea, gamma-glutamyl transpeptidase, age and sex.
In one embodiment, the cause of chronic liver disease is excessive alcohol consumption and the FibroMeter is based on alpha-2 macroglobulin, hyaluronic acid (or hyaluronate), prothrombin index and age. In another embodiment, the cause of chronic liver disease is excessive alcohol consumption and the FibroMeter is based on alpha-2 macroglobulin, hyaluronic acid (or hyaluronate), and prothrombin index.
In one embodiment, the cause of chronic liver disease is non-alcoholic fatty liver disease and the FibroMeter is based on platelets, aspartate aminotransferase (AST), gamma-glutamyl transpeptidase, bilirubin, alanine aminotransferase (ALT), ferritin, glucose and age. In another embodiment, the cause of chronic liver disease is non-alcoholic fatty liver disease and the FibroMeter is based on platelets, aspartate aminotransferase (AST), alanine aminotransferase (ALT), ferritin, glucose, age and weight.
The present invention also relates to a non-invasive method leading to a score obtained by a mathematical function, such as for example a binary logistic regression, combining at least one marker from a blood test and imaging data, preferably Fibroscan data (also known as Vibration-Controlled Transient Elastography or VCTE), for assessing, with a high accuracy, the presence or the severity of fibrosis in an individual.
In one embodiment, the present invention also relates to a non-invasive method leading to a score obtained by a mathematical function, such as for example a binary logistic regression, combining the biological and/or clinical markers from a blood test and imaging data, preferably Fibroscan data (also known as Vibration-Controlled Transient Elastography or VCTE), for assessing, with a high accuracy, the presence or the severity of fibrosis in an individual.
As detailed hereinabove, blood tests result in a score obtained by the combination of markers, in particular biological markers and optionally clinical markers. Examples of blood test include, without being limited to, APRI, FIB-4, Fibrotest, ELF score, Zeng score, FibroMeter, Fibrospect, and Hepascore. In other words, according to the present invention, the markers of a blood test or the markers constitutive of a blood test are the markers combined in the blood test to obtain a single score.
According to the present invention, biological marker refers to a variable that may be measured in a sample from the individual, said sample being a bodily fluid sample, such as, for example, a blood, serum or urine sample, preferably a blood or serum sample.
Thus measuring the biological markers may consist in: the counting of cells in the blood (e.g. platelet count); the measuring of a protein concentration in the blood (e.g. alpha2-macroglogulin, haptoglobin, apolipoprotein A1, ferritin, albumin); the measuring of a compound concentration in the blood (e.g. urea, bilirubin, hyaluronic acid, glucose); the measuring of an enzyme activity in the blood (e.g. gamma-glutamyl transpeptidase, aspartate aminotransferase, alanine aminotransferase); or the assessment of the clotting ability of the blood (prothrombin index). Methods for carrying out such assays or counts are commonly used in biomedical laboratories and very well known in the field of diagnostics in hepatology. These methods may use one or more monoclonal or polyclonal antibodies that recognize said protein in immunoassay techniques (such as, for example, radioimmunoassay or RIA, ELISA assays, Western blot, etc.), the analysis of the amounts of mRNA for said protein using the techniques of Northern blot, slot blot or PCR type, techniques such as an HPLC optionally combined with mass spectrometry, etc. The abovementioned enzyme activity assays use assays carried out on at least one substrate specific for each of these enzymes. International patent application WO 03/073822 lists methods that can be used to quantify alpha2 macroglobulin (A2M) and hyaluronic acid (HA or hyaluronate).
By way of examples, and in a non-exhaustive manner, a list of commercial kits or assays that can be used for the measurements of biomarkers carried out in the method of the invention, on blood samples, is given hereinafter:
obtaining a blood sample from the individual and measuring at least one biological marker in the blood sample to obtain at least one biological marker value, wherein said biological marker is selected from total cholesterol, HDL cholesterol, LDL cholesterol, AST (aspartate aminotransferase), ALT (alanine aminotransferase), platelets, prothrombin time or prothrombin index or INR (International Normalized Ratio), hyaluronic acid (or hyaluronate), hemoglobin, triglycerides, alpha-2 macroglobulin, gamma-glutamyl transpeptidase (GGT), urea, bilirubin or total bilirubin, apolipoprotein A1, type III procollagen N-terminal propeptide, gamma-globulins, sodium, albumin, ferritin, glucose, alkaline phosphatases, YKL-40 (human cartilage glycoprotein 39), tissue inhibitor of matrix metalloproteinase 1 (TIMP-1), TGF, cytokeratin 18 (CK18), matrix metalloproteinase 2 (MMP-2) to 9 (MMP-9), haptoglobin, alpha-fetoprotein, creatinine, leukocytes, neutrophils, segmented leukocytes, segmented neutrophils, monocytes, and ratios and mathematical combinations thereof; and/or
obtaining at least one clinical marker value from measuring at least one clinical marker in the individual, wherein said marker is selected from body weight, body mass index, age, sex, hip perimeter, abdominal perimeter and ratios thereof; and
obtaining a result from using at least one measuring device to practice a non-invasive physical method for diagnosing liver fibrosis, wherein the physical method is further defined as elastometry; and
performing a mathematical function to combine the at least biological marker value and/or the at least one clinical marker value with the result of the physical method for diagnosing liver function to obtain a single score useful for the diagnosis of the presence and/or severity of a liver pathology and/or of monitoring the effectiveness of a curative treatment against a liver pathology in the individual.
In one embodiment, the method of the invention comprises:
obtaining at least two values from measuring at least two biological and/or clinical markers selected from platelet, aspartate aminotransferase (AST or ASAT), alanine aminotransferase (ALT or ALAT), hyaluronic acid (or hyaluronate), bilirubin, total bilirubin, alpha2-macroglobulin, gamma-glutamyl transpeptidase (GGT), haptoglobin, apolipoprotein A1, prothrombin index, urea, ferritin, glucose, type III procollagen N-terminal propeptide, tissue inhibitor of matrix metalloproteinase 1 (TIMP-1), age and sex;
obtaining a result from using at least one measuring device to practice a non-invasive physical method for diagnosing liver fibrosis, wherein the physical method is further defined as elastometry; and
performing a mathematical function to combine the at least two values with the result of the physical method for diagnosing liver function to obtain a single score useful for the diagnosis of the presence and/or severity of a liver pathology and/or of monitoring the effectiveness of a curative treatment against a liver pathology in the individual.
In one embodiment, the method of the invention comprises:
obtaining at least two values from measuring at least two biological and/or clinical markers selected from platelet, aspartate aminotransferase (AST or ASAT), alanine aminotransferase (ALT or ALAT), hyaluronic acid (or hyaluronate), bilirubin, total bilirubin, alpha2-macroglobulin, gamma-glutamyl transpeptidase (GGT), haptoglobin, apolipoprotein A1, prothrombin index, urea, ferritin, glucose, type III procollagen N-terminal propeptide, tissue inhibitor of matrix metalloproteinase 1 (TIMP-1), age, sex and weight;
obtaining a result from using at least one measuring device to practice a non-invasive physical method for diagnosing liver fibrosis, wherein the physical method is further defined as elastometry; and
performing a mathematical function to combine the at least two values with the result of the physical method for diagnosing liver function to obtain a single score useful for the diagnosis of the presence and/or severity of a liver pathology and/or of monitoring the effectiveness of a curative treatment against a liver pathology in the individual.
In one embodiment, the method of the invention comprises:
obtaining at least two values from measuring at least two biological and/or clinical markers selected from platelet, aspartate aminotransferase (AST or ASAT), alanine aminotransferase (ALT or ALAT), hyaluronic acid (or hyaluronate), bilirubin, total bilirubin, alpha2-macroglobulin, gamma-glutamyl transpeptidase (GGT), haptoglobin, apolipoprotein A1, prothrombin index, urea, ferritin, glucose, age and sex;
obtaining a result from using at least one measuring device to practice a non-invasive physical method for diagnosing liver fibrosis, wherein the physical method is further defined as elastometry; and
performing a mathematical function to combine the at least two values with the result of the physical method for diagnosing liver function to obtain a single score useful for the diagnosis of the presence and/or severity of a liver pathology and/or of monitoring the effectiveness of a curative treatment against a liver pathology in the individual.
In another embodiment, the method of the invention comprises:
obtaining at least two values from measuring at least two biological and/or clinical markers selected from platelet, aspartate aminotransferase (AST or ASAT), alanine aminotransferase (ALT or ALAT), hyaluronic acid (or hyaluronate), bilirubin, total bilirubin, alpha2-macroglobulin, gamma-glutamyl transpeptidase (GGT), haptoglobin, apolipoprotein A1, prothrombin index, urea, ferritin, glucose, age, sex and weight;
obtaining a result from using at least one measuring device to practice a non-invasive physical method for diagnosing liver fibrosis, wherein the physical method is further defined as elastometry; and
performing a mathematical function to combine the at least two values with the result of the physical method for diagnosing liver function to obtain a single score useful for the diagnosis of the presence and/or severity of a liver pathology and/or of monitoring the effectiveness of a curative treatment against a liver pathology in the individual.
In one embodiment, the method of the invention comprises:
obtaining at least three values from measuring at least three biological and/or clinical markers selected from alpha-2 macroglobulin, hyaluronic acid (or hyaluronate), prothrombin index, platelets, aspartate aminotransferase (AST), urea, gamma-glutamyl transpeptidase (GGT), bilirubin, alanine aminotransferase (ALT), ferritin, glucose, age and sex;
obtaining a result from using at least one measuring device to practice a non-invasive physical method for diagnosing liver fibrosis, wherein the physical method is further defined as elastometry; and
performing a mathematical function to combine the at least three values with the result of the physical method for diagnosing liver function to obtain a single score useful for the diagnosis of the presence and/or severity of a liver pathology and/or of monitoring the effectiveness of a curative treatment against a liver pathology in the individual.
In another embodiment, the method of the invention comprises:
obtaining at least three values from measuring at least three biological and/or clinical markers selected from alpha-2 macroglobulin, hyaluronic acid (or hyaluronate), prothrombin index, platelets, aspartate aminotransferase (AST), urea, gamma-glutamyl transpeptidase (GGT), alanine aminotransferase (ALT), ferritin, glucose, age, sex and weight;
obtaining a result from using at least one measuring device to practice a non-invasive physical method for diagnosing liver fibrosis, wherein the physical method is further defined as elastometry; and
performing a mathematical function to combine the at least three values with the result of the physical method for diagnosing liver function to obtain a single score useful for the diagnosis of the presence and/or severity of a liver pathology and/or of monitoring the effectiveness of a curative treatment against a liver pathology in the individual.
In another embodiment, the method of the invention comprises:
obtaining seven values from measuring in a blood sample obtained from the individual: alpha-2 macroglobulin, hyaluronic acid (or hyaluronate), prothrombin index, platelets, aspartate aminotransferase (AST), urea and measuring in the individual: age;
obtaining a result from using at least one measuring device to practice a non-invasive physical method for diagnosing liver fibrosis, wherein the physical method is further defined as elastometry; and
performing a mathematical function to combine the seven values with the result of the physical method for diagnosing liver function to obtain a single score useful for the diagnosis of the presence and/or severity of a liver pathology and/or of monitoring the effectiveness of a curative treatment against a liver pathology in the individual.
In another embodiment, the method of the invention comprises:
obtaining eight values from measuring in a blood sample obtained from the individual: alpha-2 macroglobulin, hyaluronic acid (or hyaluronate), prothrombin index, platelets, aspartate aminotransferase (AST), and urea and measuring in the individual: age and sex;
obtaining a result from using at least one measuring device to practice a non-invasive physical method for diagnosing liver fibrosis, wherein the physical method is further defined as elastometry; and
performing a mathematical function to combine the eight values with the result of the physical method for diagnosing liver function to obtain a single score useful for the diagnosis of the presence and/or severity of a liver pathology and/or of monitoring the effectiveness of a curative treatment against a liver pathology in the individual.
In another embodiment, the method of the invention comprises:
obtaining eight values from measuring in a blood sample obtained from the individual: alpha-2 macroglobulin, gamma-glutamyl transpeptidase, prothrombin index, platelets, aspartate aminotransferase (AST), and urea and measuring in the individual: age and sex;
obtaining a result from using at least one measuring device to practice a non-invasive physical method for diagnosing liver fibrosis, wherein the physical method is further defined as elastometry; and
performing a mathematical function to combine the eight values with the result of the physical method for diagnosing liver function to obtain a single score useful for the diagnosis of the presence and/or severity of a liver pathology and/or of monitoring the effectiveness of a curative treatment against a liver pathology in the individual.
In another embodiment, the method of the invention comprises:
obtaining four values from measuring in a blood sample obtained from the individual: alpha-2 macroglobulin, hyaluronic acid (or hyaluronate), and prothrombin index and measuring in the individual: age;
obtaining a result from using at least one measuring device to practice a non-invasive physical method for diagnosing liver fibrosis, wherein the physical method is further defined as elastometry; and
performing a mathematical function to combine the four values with the result of the physical method for diagnosing liver function to obtain a single score useful for the diagnosis of the presence and/or severity of a liver pathology and/or of monitoring the effectiveness of a curative treatment against a liver pathology in the individual.
In another embodiment, the method of the invention comprises:
obtaining three values from measuring in a blood sample obtained from the individual: alpha-2 macroglobulin, hyaluronic acid (or hyaluronate), and prothrombin index;
obtaining a result from using at least one measuring device to practice a non-invasive physical method for diagnosing liver fibrosis, wherein the physical method is further defined as elastometry; and
performing a mathematical function to combine the three values with the result of the physical method for diagnosing liver function to obtain a single score useful for the diagnosis of the presence and/or severity of a liver pathology and/or of monitoring the effectiveness of a curative treatment against a liver pathology in the individual.
In another embodiment, the method of the invention comprises:
obtaining eight values from measuring in a blood sample obtained from the individual: platelets, aspartate aminotransferase (AST), gamma-glutamyl transpeptidase, bilirubin, alanine aminotransferase (ALT), ferritin, and glucose and measuring in the individual: age;
obtaining a result from using at least one measuring device to practice a non-invasive physical method for diagnosing liver fibrosis, wherein the physical method is further defined as elastometry; and
performing a mathematical function to combine the eight values with the result of the physical method for diagnosing liver function to obtain a single score useful for the diagnosis of the presence and/or severity of a liver pathology and/or of monitoring the effectiveness of a curative treatment against a liver pathology in the individual.
In another embodiment, the method of the invention comprises:
obtaining seven values from measuring in a blood sample obtained from the individual: platelets, aspartate aminotransferase (AST), alanine aminotransferase (ALT), ferritin, and glucose and measuring in the individual: age and weight;
obtaining a result from using at least one measuring device to practice a non-invasive physical method for diagnosing liver fibrosis, wherein the physical method is further defined as elastometry; and
performing a mathematical function to combine the seven values with the result of the physical method for diagnosing liver function to obtain a single score useful for the diagnosis of the presence and/or severity of a liver pathology and/or of monitoring the effectiveness of a curative treatment against a liver pathology in the individual.
Preferably, the physical method is selected from the group consisting of ultrasonography, especially Doppler-ultrasonography and elastometry ultrasonography and velocimetry ultrasonography, IRM, and MNR, especially MNR elastometry or velocimetry.
In one embodiment, the physical method of diagnosing liver fibrosis is elastometry. In one embodiment, elastometry is selected from the group consisting of Fibroscan (also known as Vibration-Controlled Transient Elastography or VCTE), Acoustic Radiation Force Impulse imaging (ARFI imaging), shear wave elastography, MR elastography, supersonic elastometry, transient elastography (TE) and Mill stiffness. Preferably, the data are LSE data. According to a preferred embodiment of the invention, the data are issued from a Fibroscan, also known as Vibration-Controlled Transient Elastography (VCTE).
According to a preferred embodiment, the mathematical logistic regression function is the following:
score=a0+a1x1+azx2+ . . .
wherein ai coefficients are constants and xi are independent variables.
This score corresponds to the p logit wherein p is the probability of presence of a significant or severe fibrosis, or of cirrhosis.
p is calculated as follows:
p=exp(a0+a1x1+a2x2+ . . . )/(1+exp(a0+a1x1+a1x2+ . . . ))
or p=1/(1+exp(−a0−a1x1−a2x2− . . . ))
wherein ai and xi correspond to those of the score formula.
The presence of a lesion (for example significant fibrosis) is determined by a probability p higher than a diagnostic threshold generally equal to 0.5 or equal to maximal Youden index (Se+Spe−1) or equal to maximal diagnostic performance (unless otherwise specified).
According to one embodiment of the invention, for significant fibrosis, coefficients that may be used in the binary regression of the method of the invention are the following: 3.9066 FM+0.1870 FS−2.8345, Where FM: FibroMeter value, FS: Fibroscan value.
According to another embodiment of the invention, for cirrhosis, coefficients that may be used in the binary regression of the method of the invention are the following: 3.6128 FM+0.1484 FS−6.4999
According to yet another embodiment of the invention, for severe fibrosis, coefficients that may be used in the binary regression of the method of the invention are the following: 3.3135 FM+0.1377 FS−4.2485.
Where FM: FibroMeter value, FS: Fibroscan value.
Scores of binary logistic regression: beta coefficients with 95% confidence intervals specifically observed in chronic viral hepatitis C, may be for example:
According to a preferred embodiment of the invention, the blood score is the FibroMeter score and the physical method data are LSE data through ultrasonographic elastometry. In all populations tested, the FibroMeter was always identified as the first independent predictor of significant fibrosis despite a slightly lower AUROC than LSE. Indeed, the FibroMeter provided the highest diagnostic accuracy in logistic regression. In addition, the FibroMeter might be the most accurate and robust among common blood tests (18). Among the various evaluations in the Applicant's study, the synchronous combination of FibroMeter and LSE was the most accurate for the diagnosis of significant fibrosis as well as for cirrhosis.
Advantageously, the presence or severity of liver disease or condition is diagnosed in two steps, first step being the FibroMeter blood test and second step being collecting data from a physical method, preferably LSE data, and wherein the combination of FibroMeter blood test and said data is performed through logistic regression.
According to the method of the invention, the liver biopsy/accuracy ratio may range from 0.10 for cirrhosis to 0.22 for clinically significant fibrosis; whereas this ratio ranges from 0.25 to 0.51 in classical algorithms without synchronous combination.
According to one embodiment, the method of the invention leads to a significant fibrosis score, called significant fibrosis-index (SF-index). This score was set up by using results from experimentations in a group of patients with both blood tests (preferably FibroMeter) and imaging data (preferably LSE data).
According to another embodiment of the invention, the method of the invention leads to a cirrhosis score, called C-index implementing the method of the invention, for the diagnosis of patients with cirrhosis.
Regarding the gain in accuracy provided by the method of the invention, the Applicant noticed that the method of the invention provided a significantly higher AUROC than the blood test or physical data, for example LSE, alone, especially for the diagnosis of significant fibrosis, and a gain in predictive values for cirrhosis (see for example Table 4 of Example 2).
Regarding the SF-index, it inherited the lowest misclassification rate provided by each single test in each fibrosis stage: the blood test in F0/1 stages, and LSE in F≧2 stages (see for example
Regarding the C-index, although it afforded no apparent significant gain in accuracy for cirrhosis diagnosis compared to LSE alone (see for example Table 3, 4 of Example 2), it did provide two advantages: 1) it resolved 68.4% of discordant cases between LSE and the blood test (see for example Table 5 of Example 2), and 2) the patient rate with ≧90% predictive values was significantly higher than with LSE or blood test alone (see for example Table 6 of Example 2), thus resulting in a very low rate of Liver Biopsy required in the algorithm (9%). Finally, the C-index allowed for a non-invasive diagnosis of cirrhosis in 100% of patients, with 90.3% accuracy, by considering three intervals of reliable individual diagnosis: no cirrhosis, F≧2, and cirrhosis, without liver biopsy requirement.
Regarding sequential algorithms, as demonstrated in a recent preliminary study (34), the Applicant showed that the Padova algorithm had a significantly higher diagnostic accuracy for significant fibrosis than the Bordeaux and Angers algorithms. However, this accuracy was mainly due to the high rate of required Liver Biopsy. In fact, to evaluate the clinical interest of an algorithm, the rates of required Liver Biopsy and of correctly classified patients among those not requiring Liver Biopsy are more appropriate descriptors than overall diagnostic accuracy. In that respect, the Angers algorithm provided the best solution between high diagnostic accuracy (91.9%) and the lowest rate of required Liver Biopsy (20.2%). Finally, it should be noticed that a part of apparently misclassified patients provided by an algorithm are in fact attributable to the misclassification of Liver Biopsy used as the reference (sampling error and observer variability).
In the work performed to reduce to practice the present invention, accuracies for the diagnosis of significant fibrosis or cirrhosis of the Bordeaux and Padova algorithms were similar to those previously published (16, 34, 35). Thus, the Applicant provides herein an independent external validation of these algorithms that were the previous reference in terms of algorithms. Interestingly, accuracies of the three algorithms were not significantly different between patients with chronic viral hepatitis and those with other cause of CLD, except for cirrhosis with the Angers C-algorithm. Because the Bordeaux and Padova algorithms were elaborated in chronic viral C hepatitis, the present invention states that these sequential algorithms can also be extended to other causes of CLD.
Thus, the method of the invention significantly increases the diagnostic accuracy of tests for significant fibrosis, and increases the reliability of individual diagnosis via predictive values for significant fibrosis and cirrhosis. The combination resolves discordant results between non-invasive tests and reduces non-concordant results with liver biopsy (LB). It also decreases the LB requirement in the traditional diagnosis of significant fibrosis or cirrhosis when they are the unique binary diagnostic targets. Also, the new method of reliable individual diagnosis, which adds an intermediate diagnostic target to the previous binary diagnostic target, suppresses or considerably diminishes any LB requirement. Finally, a simple sequential algorithm, including the synchronous blood test score+imaging data combination, provided high diagnostic accuracy while lowering LB requirement, notably to less than 10% for cirrhosis diagnosis.
According to an embodiment of the invention, the method of the invention may also include, in a further step, the combination of a SF-index and a C-index in an algorithm based on the diagnostic reliable intervals (see for example table 5 of example 1).
The invention will be better understood in view of the following examples, which are read with consideration of the figures:
The following examples may be read, when appropriate, with references to the figures, and shall not be considered as limiting in any way the scope of this invention.
Blood fibrosis tests and liver stiffness measured by ultrasonographic elastometry like Fibroscan™ are well correlated with the histological stages of fibrosis. In this study, we aimed to improve non-invasive diagnosis of liver fibrosis stages via a novel combination of blood tests and Fibroscan.
349 patients with chronic hepatitis C across three centres were included in the study. For each patient, a liver biopsy and the following fibrosis tests were done: Fibroscan (FS), Fibrotest, FibroMeter (FM, for significant fibrosis or cirrhosis), Hepascore, Fib4, and APRI. Reference for liver fibrosis was Metavir F staging. Fibrosis tests independently associated with significant fibrosis (F≧2) or cirrhosis (F4) were identified by stepwise binary logistic regression repeated on 1000 bootstrap samples of 349 patients.
Prevalences of diagnostic targets were, significant fibrosis: 67.9%, cirrhosis: 11.8%. Multivariate analyses on the 1000 bootstrap samples indicated that FM and FS were the tests most frequently associated with significant fibrosis or cirrhosis. We thus implemented 2 new scores combining FS and FM by using binary logistic regression: F2-score for the diagnosis of significant fibrosis and F4-score for cirrhosis. F2-score provided reliable diagnosis of significant fibrosis, with predictive values ≧90%, in 55.6% of patients. F4-score provided reliable diagnosis of cirrhosis, with predictive values ≧95%, in 89.1% of patients. An algorithm combining F2-score and F4-score, as a function of their interval of highest diagnostic accuracy, produced a new diagnostic classification (% of patients): F0/1 (9.5%), F1/2 (17.2%), F2±1 (27.2%), F2/3 (33.2%), F3±1 (10.9%), and F4 (2.0%). According to liver biopsy results, this new classification provided 88.0% diagnostic accuracy, outperforming FM (67.6%, p<10−3), FS (55.3%, p<10−3) and Fibrotest (33.2%, p<10−3) classifications. Furthermore, diagnostic accuracy of the new classification did not significantly differ over the 3 centres (92.9%, 85.7%, and 86.3%, p=0.20) or between patients with biopsies < or ≧25 mm (respectively: 87.2% versus 88.5%, p=0.72).
The non-invasive diagnosis of liver fibrosis in patients with chronic hepatitis C is improved by a combination of FibroMeter and Fibroscan. A new classification using the two scores derived from the test combination is much more accurate than single fibrosis tests and provides a non-invasive diagnosis in 100% of patients with 88% accuracy without any liver biopsy.
The exploratory set included 349 patients. 132 patients from the 512 of the Fibrostar study were already included in the exploratory set. We thus removed these patients from the validation set which finally included 380 patients. The characteristics of both exploratory and validation sets are detailed in the Table 1 of Example 1. Among the 2 groups, 93.5% of liver biopsy were considered as reliable.
Significant Fibrosis—
The fibrosis tests most frequently selected by the stepwise binary logistic regression repeated on the 1000 bootstrap samples for the diagnosis of significant fibrosis were LSE and FibroMeter (Table 2 of Example 1). F≧2-index was implemented by including these 2 fibrosis tests as independent variables in a binary logistic regression performed in the whole population of the exploratory set. The regression score of F≧2-index, specifically designed for the diagnosis of significant fibrosis, was: 3.9066 FibroMeter+0.1870 LSE result−2.8345. F≧2-index had a significantly higher AUROC than FibroMeter and LSE (Table 3 of Example 1).
The fibrosis tests most frequently selected by the 1000 bootstrap multivariate analyses were LSE and FibroMeter (Table 2 of Example 1). The regression score of F≧3-index including these 2 fibrosis tests and specifically designed for the diagnosis of severe fibrosis was: 3.3135 FibroMeter+0.1377 LSE result−4.2485. F≧3-index had a higher AUROC than FM and LSE, but the difference was significant only with FibroMeter (Table 3 of Example 1).
The fibrosis tests most frequently selected by the 1000 bootstrap multivariate analyses were also LSE and FibroMeter (Table 2 of Example 1). The regression score of F4-index including these 2 fibrosis tests and specifically designed for the diagnosis of cirrhosis was: 3.6128 FibroMeter+0.1484 LSE result−6.4999. F4-index had a higher AUROC than FM and LSE, but the difference was significant only with FibroMeter (Table 3 of Example 1).
F≧2-index included 32 (9.2%) patient in the ≧90% negative predictive value (NVP) interval and 161 (46.1%) patients in the ≧90% positive predictive value (PPV) interval (Table 4 of Example 1). Thus, F≧2-index allowed a reliable diagnosis of significant fibrosis with ≧90% accuracy in 55.3% of patients, versus 33.8% with LSE (p<10−3) and 55.6 with FibroMeter (p=1.00). The indeterminate interval between F≧2-index values >0.248 and <0.784 was divided into two new intervals according to the statistical cut-off of 0.500. 90.2% of the patients included in the lower interval (>0.248-<0.500) had F1/2 stages according to liver biopsy results, and 96.8% of patients included in the higher interval (≧0.500-<0.784) had F1/2/3 stages (
F≧3-index included 174 (49.9%) patients in the intervals of ≧90% predictive values for severe fibrosis (Table 4 of Example 1), versus 41.8% with FibroMeter (p<10−3) and 46.4% with LSE (p=0.235). By dividing the intermediate interval of F≧3-index according to the statistical cut-off of 0.500, F≧3-index provided 4 IRD (F<2, F2±1, F≧2, F≧3;
F4-index included 313 (89.7%) patients in the intervals of ≧95% predictive values for cirrhosis (Table 4 of Example 1), versus 65.9% with FibroMeter (p<10−3) and 87.4% with LSE (p=0.096). Dividing the intermediate interval according to the cut-off 0.500 did not allow for distinguish two different groups. Finally, F4-index provided 3 IRD (F<3, F≧2, and F4) which well classified 95.1% of patients (
The first classification (classification A) was derived from both F≧2- and F≧3-indexes used with their IRD (Table 5 of Example 1). Classification A included 6 classes: F0/1, F1/2, F2±1, F2/3, F≧2, and F≧3. It provided 86.2% diagnostic accuracy in the exploratory set.
The second classification (classification B) was derived from the IRD of F≧2- and F4 indexes (Table 5 of Example 1). Classification B included 6 classes (F0/1, F1/2, F2±1, F2/3, F≧2, F4) and provided 88.3% diagnostic accuracy (p=0.143 vs classification A).
The third classification (classification C) was derived from the IRD for significant fibrosis of FibroMeter, and those for severe fibrosis of LSE (Table 5 of Example 1). Results of FibroMeter and LSE RDI were discordant in 2 patients which had thus undetermined diagnosis (Table 5 of Example 1). Classification C finally included 8 classes (F0/1, F1, F1/2, F2, F2±1, F2/3, F≧2, F≧3) and provided 84.0% diagnostic accuracy (p=0.229 vs classification A).
The rates of well classified patients by the new classifications A and B were not significantly different in the validation set (respectively: 84.2% vs 82.4%, p=0.149), but were significantly higher than those of FibroMeter, LSE and Fibrotest (Table 6 of Example 1). One patient had undetermined diagnosis with the classification C that provided 70.3% diagnostic accuracy. Among already published classifications, FibroMeter provided the highest diagnostic accuracy (69.7%, p<0.029 vs LSE and Fibrotest), and Fibrotest the lower (p<10−3 vs others). Finally, according to their diagnostic accuracies in the validation set, the classifications were ordered as follow: A, B>C>FibroMeter>LSE>Fibrotest (Table 6 of Example 1).
In the whole study population, we performed a stepwise binary logistic regression including age, sex, biopsy length, Metavir F, and IQR/median as independent variables. Misclassification by classification A was independently associated only with the ratio IQR/median. In the validation set, classification A provided 88.2% diagnostic accuracy in patients with IQR/median <0.21 versus 70.1% in patients with IQR/median≧0.21 (p=0.010). In the subgroup of patients with IQR/median <0.21, classification A had the highest diagnostic accuracy with p=0.007 versus classification B (85.5%), and p<10−3 versus others.
Antiviral therapy was considered when FibroMeter classification was ≧F2/3, LSE: ≧F2, Fibrotest: ≧F2, classifications A and B: ≧F2±1, and classification C: ≧F2. By using classification A, 12.1% of patients in the validation set were considered for antiviral therapy whereas they had no/mild fibrosis at liver biopsy (Table 7 of Example 1). On the other hand, 9.7% of patients had no treatment whereas they had significant fibrosis at liver biopsy. Finally, classification A provided the highest rate of patients well managed for antiviral therapy (78.2%, p<0.040 versus others classifications).
Stepwise binary logistic regressions were performed on 1000 bootstrap samples of 349 subjects from the exploratory set. The table depicts the number of times any fibrosis test was selected across the 1000 multivariate analyses. For each diagnostic target, LSE and FibroMeter were the mostly selected variables.
aSF-index for significant fibrosis, X-index for severe fibrosis, and C-index for cirrhosis.
a6 classes (de Ledinghen, GCB 2008);
b4 classes (Ziol 2005),
c4 classes (Stebbing 2009 + ≧9.6 kPa pour F ≧3),
d3 classes (Stebbing 2009)
aIndication for antiviral therapy: Classifications A and B: ≧F2 ± 1; Classification C: ≧F2; FibroMeter: ≧F2/3; Fibroscan VDL: ≧F2; Fibroscan Ziol and Stebbing 4 classes: ≧F2; Fibroscan Stebbing 3cl: ≧F2/3; Fibrotest: ≧F2
390 patients with chronic liver disease (CLD) hospitalized for a percutaneous liver biopsy at the University Hospitals of Angers and Bordeaux (France) were enrolled. 194 patients were included from April 2004 to June 2007 at the Angers site (group A, exploratory set), and 196 from September 2003 to April 2007 at the Bordeaux site (group B, validation set). Patients with the following cirrhosis complications were not included: ascites, variceal bleeding, systemic infection, and hepatocellular carcinoma. The non-invasive assessment of liver fibrosis by blood fibrosis tests and LSE was performed within one week prior to liver biopsy.
Percutaneous liver biopsy was performed using Menghini's technique with a 1.4-1.6 mm diameter needle. In each site, liver fibrosis was evaluated by a senior pathologist specialized in hepatology according to Metavir staging (with a consensus reading in Angers). Significant fibrosis was defined by Metavir stages F≧2. Liver fibrosis evaluation was considered as reliable when biopsy length was ≧15 mm and/or portal tract number ≧8 (17).
The following blood tests were calculated according to published formulas or patents: APRI, FIB-4, Fibrotest, Hepascore, and FibroMeter (FM). Cause-specific formulas were used for FibroMeter (9, 18, 19). All blood assays were performed in the same laboratories of each site. The inter-laboratory reproducibility was excellent for these tests (20).
LSE (FibroScan®, EchoSens™, Paris, France) was performed by an experienced observer (>50 LSE before the study), blinded for patient data. LSE conditions were those recommended by the manufacturer, as detailed elsewhere (21, 22). LSE was stopped when 10 valid measurements were recorded. The LSE result was expressed in kPa and corresponded to the median of all valid measurements performed within the LSE. Inter-quartile range (kPa) was defined as previously described (21).
Quantitative variables were expressed as mean±standard deviation, unless otherwise specified. When necessary, diagnostic cut-off values of fibrosis tests were calculated according to the highest Youden index (sensitivity+specificity −1). This technique allows maximizing the diagnostic accuracy with equilibrium between a high sensitivity and a high specificity by selecting an appropriate diagnostic cut-off. The diagnostic cut-off is here the values of blood test or LSE that distinguishes the patients as having or not the diagnostic target (significant fibrosis or cirrhosis).
The performance of fibrosis tests was mainly expressed as the area under the receiver operating characteristic curve (AUROC). The reliable individual diagnosis was determined either by the traditional negative (NPV) and positive (PPV) predictive values, or by the recently described method of reliable diagnosis intervals (18) (see Appendix for precise definitions). AUROCs were compared by the Delong test (23).
Combinations of blood tests and LSE were studied in 3 populations: group A, B, and A+B. In each population, we performed a forward binary logistic regression using significant fibrosis determined on liver biopsy as the dependent variable, and blood fibrosis tests and LSE results as independent variables. Then, by using the regression score provided by the multivariate analysis, we implemented a new fibrosis test for the diagnosis of significant fibrosis. The same methodology was used for the diagnosis of cirrhosis.
Sample size was determined to show a significant difference for the diagnosis of significant fibrosis between FM and synchronous combination in the exploratory population. With α risk: 0.05, β risk: 0.20, significant fibrosis prevalence: 0.70, AUROC correlation: 0.70, and a bilateral test, the sample size was 159 patients for the following hypothesis of AUROC: FM: 0.84, synchronous combination: 0.90. The software programs used for statistical analyses were SPSS for Windows, version 11.5.1 (SPSS Inc., Chicago, Ill., USA) and SAS 9.1 (SAS Institute Inc., Cary, N.C., USA).
The characteristics of the 390 patients are summarized in Table 1 of Example 2. Mean age of patients was 52.4 years, 67.9% were male, and 74.4% had significant fibrosis. 89.5% of patients had a liver biopsy considered as reliable. Liver Stiffness Evaluation failure occurred in 12 patients (overall failure rate: 3.1%). Among the 390 patients included, 332 had all 5 blood tests and LSE available.
aBy t-test or χ2 between the groups A and B
LSE AUROC was significantly higher than that of Hepascore, FIB-4, and APRI for the diagnosis of significant fibrosis, and was not significantly different from FibroMeter and Fibrotest AUROCs.
aBy Delong test
Combination of Non-Invasive Tests (Table 3 of Example 2)—
In each of the three populations tested, significant fibrosis defined by liver biopsy was independently diagnosed by FibroMeter at the first step and Liver Stiffness Evaluation at the second step. The regression score provided by the binary logistic regression performed in group A (exploratory set) was: 3.6224.FM+0.4408.LSE result−3.9850. This score was used to implement a diagnostic synchronous combination of FibroMeter and Liver Stiffness Evaluation called significant fibrosis-index (SF-index). This new fibrosis test was then evaluated in the validation sets: group B (Bordeaux center) and the pooled group A+B.
aVariables independently associated with significant fibrosis or cirrhosis with increasing order of step (the first step is the most accurate variable);
bCumulative diagnostic accuracy for the second step
Performance of SF-Index (Table 4 of Example 2)—
SF-index AUROCs were not significantly different between groups A and B. SF-index AUROC was significantly higher than that of FibroMeter (FM) or Liver Stiffness Evaluation (LSE) in the whole population.
aSF-index for significant fibrosis, C-index for cirrhosis
bBy Delong test
As shown on Table 4 of Example 2, SF-index inherited of the lowest misclassification rate provided by each single test in each fibrosis stage: the blood test in F0/1 stages, and LSE in F≧2 stages (see also
Discordances between fibrosis tests for the diagnostic target were calculated according to the diagnostic cut-off determined by the highest Youden index. FM and LSE were concordant in 279 (73.0%) patients of whom 88.9% were correctly classified according to liver biopsy (F<1: 77.0%, 94.3%). FM and LSE were discordant in the 103 (27.0%) remaining patients of whom 68 (66.0%) were correctly classified by SF-index according to liver biopsy results (Table 5 of Example 2). Finally, SF-index correctly classified 316 (82.7%) patients and improved correct classification (i.e., discordances between FM and LSE resolved by SF-index) in 33 (8.6%) patients.
Moreover, the SF-index resolved 66% of discordant cases between the blood test and LSE (Table 5 of Example 2).
aRespective diagnostic cut-off values used for significant fibrosis or cirrhosis, according to the highest Youden index: FM: 0.538 and 0.873; LSE: 6.9 and 13.0 kiloPascals; FM + LSE index: 0.753 (SF-index) and 0.216 (C-index)
bClassification by SF-index for significant fibrosis or C-index for cirrhosis expressed as correct or incorrect according to liver biopsy.
cClassification of both tests based on liver biopsy. “Discordant” means than one test is correct and the other one is incorrect.
dFavorable (68) − unfavorable (35) effect = improvement (33)
eFavorable (54) − unfavorable (25) effect = improvement (29)
SF-index included significantly more patients than FM or LSE in the classical intervals of ≧90% predictive values (see Appendix for precise definition), especially in the ≦90% NPV interval (Table 6 of Example 2). By using SF-index with ≧90% predictive values in 81.7% of patients and liver biopsy required in the remaining 18.3% of patients, a correct diagnosis of significant fibrosis based on liver biopsy was obtained in 91.9% of patients (Table 6 of Example 2). This two-step sequential algorithm was called Angers SF-algorithm (
With this recently described method (18), accuracy is made ≧90% in the interval(s) between the previous intervals of 90% predictive values by changing the diagnostic target. The interest is to offer a reliable diagnosis for all patients. In the indeterminate interval determined by the ≧90% predictive values of SF-index, the proportion of Metavir fibrosis stages was F0: 20.0%, F1: 40.0%, and F2: 32.9% according to LIVER BIOPSY (
We compared the Angers SF-algorithm to those previously published in Bordeaux (24) and in Padova (16). The population tested was the 332 patients having Fibrotest, FibroMeter, APRI, and LSE available. The Padova algorithm had significantly higher accuracy (95.2%) compared to other algorithms due to a significantly higher rate of required LB. The Angers algorithm had a significantly lower rate of required liver biopsy compared to other algorithms. Thus, Angers SF-algorithm had the best compromise between high correct classification and low liver biopsy requirement, reflected by a much lower liver biopsy/accuracy ratio.
LSE had a significantly higher AUROC than the blood tests for the diagnosis of cirrhosis.
The most accurate combination of fibrosis tests for the diagnosis of cirrhosis was LSE+FM. The regression score provided by the binary logistic regression performed in the group A (exploratory set) was: 0.1162.LSE result+1.9714.FM−4.6616. This score was used to implement a diagnostic synchronous combination of LSE and FM called cirrhosis-index (C-index). This new fibrosis test was then evaluated in the validation sets: group B (Bordeaux center) and the pooled group A+B.
C-index AUROCs were not significantly different between groups A and B. In each group tested, C-index had a significantly higher AUROC than FM, but the difference with the LSE AUROC was not significant.
Discordances Between LSE and FM—
FM and LSE were concordant in 303 (79.3%) patients of whom 90.8% were correctly classified according to LIVER BIOPSY (F≦3: 94.7%, F4: 82.1%). FM and LSE were discordant in the 79 (20.7%) remaining patients of whom 54 (68.4%) were correctly classified by C-index according to LIVER BIOPSY results (Table 5 of Example 2). Finally, C-index correctly classified 329 (86.1%) patients and improved correct classification (i.e., discordances between FM and LSE resolved by C-index) in 29 (7.6%) patients.
The C-index included significantly more patients than FM or LSE in the classical intervals of ≧90% predictive values. By using C-index with ≧90% predictive values in 90.6% of patients and liver biopsy required in the remaining 9.4% of patients, a correct diagnosis of cirrhosis based on liver biopsy was obtained in 91.1% of patients (Table 6 of Example 2). This two-step sequential algorithm was called Angers C-algorithm (
In the indeterminate interval determined by the ≧90% predictive values of C-index, the proportion of Metavir fibrosis stages was F2: 11.1%, F3: 22.2%, and F4: 58.3% according to liver (
aProportion of patients for whom diagnosis remains uncertain (NPV and PPV <90%), thus requiring a liver biopsy. Comparison of patient rates by McNemar test. Significant fibrosis: LSE vs FibroMeter: p = 0.006, SF-index vs FibroMeter or LSE: p < 10−3; cirrhosis: FibroMeter vs C-index or LSE: p < 10−3, C-index vs LSE: p = 0.02.
bRate of patients correctly classified by the intervals of ≧90% (negative and positive) predictive values, among the whole population. Comparison of patient rates by McNemar test. Significant fibrosis: LSE vs FibroMeter: p = 0.005, SF-index vs FibroMeter or LSE: p < 10−3; cirrhosis: FibroMeter vs C-index or LSE: p < 10−3, C-index vs LSE: p = 0.007.
cAlgorithm is defined by a two-step procedure: the fibrosis test is initially used with the interval of ≧90% predictive values, and a liver biopsy is subsequently required for patients included in the interval of indeterminate diagnosis. Thus, algorithm accuracy is calculated as the sum of patients correctly classified by the fibrosis test in the whole population (4th result column) and liver biopsy requirement (2nd result column) where accuracy is 100% by definition. Comparison of rates by McNemar test between FibroMeter and C-index for cirrhosis: p = 0.04, others: p: NS.
The Bordeaux algorithm had significantly higher accuracy for cirrhosis compared to other algorithms. However, Angers C-algorithm had a significantly lower rate of required liver biopsy compared to other algorithms. Thus, as for significant fibrosis, Angers C-algorithm had the best compromise between high correct classification and low liver biopsy requirement, reflected by a much lower liver biopsy/accuracy ratio.
aAccuracy (%) of blood tests included in patients without liver biopsy whose proportion can be deduced from the following column. Paired comparison was not possible.
bRate (%) of liver biopsy required by the algorithm. Comparison of rates by McNemar test. Significant fibrosis: Angers vs Bordeaux: p = 0.02, Padova vs Angers or Bordeaux: p < 10−3; cirrhosis: Angers vs Bordeaux or Padova: p < 10−3; Bordeaux vs Padova: p = 0.129.
cComparison of patient rates by McNemar test. Significant fibrosis: Padova vs Angers: p = 0.02, or Bordeaux: p = 0.007; Angers vs Bordeaux: p = 0.50; cirrhosis: Bordeaux vs Angers: p = 0.04, or Padova: p < 10−3; Angers vs Padova: p = 0.007.
dRatio: rate of required liver biopsy (2nd result column)/blood test accuracy (1st result column).
This application is Continuation in Part of U.S. application Ser. No. 13/203,397 filed Aug. 25, 2011, which is a national phase application under 35 U.S.C. §371 of International Application No. PCT/EP2010/052506 filed 26 Feb. 2010, which claims priority to U.S. Provisional Application No. 61/155,659 filed 26 Feb. 2009. The entire text of each of the above-referenced disclosures is specifically incorporated herein by reference without disclaimer.
| Number | Date | Country | |
|---|---|---|---|
| 61155659 | Feb 2009 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13203397 | Aug 2011 | US |
| Child | 15368074 | US |
