Patent Application
20150118236
Subject of the present invention is a method for predicting the risk of getting a cardiovascular event in a female subject comprising:
The term “elevated level” means a level above a certain threshold level.
Neurotensin is a 13-amino acid neuropeptide derived from the prepro-neurotensin precursor and stochiometrically released together with the stable 117-amino acid peptide pro-neurotensin (P-NT) and the mature hormone binds to three different receptors, neurotensin receptor 1 and 2 (Ntsr1 and Ntsr2), which are G-protein coupled receptors and neurotensin receptor 3 (Ntsr3) which is non-G-protein coupled and also known as Sortillin-1 (SORT1).
Neurotensin is released peripherally from the small intestine as well as centrally from the hypothalamus. The peripheral secretion of neurotensin is stimulated by food-intake, especially by fat, and is known to regulate gastrointestinal motility and pancreatic and biliary secretion. Interestingly, neurotensin is implicated in appetite control as an anorectic hormone as it acutely reduces food intake following both central (intracerebroventricular) and peripheral (intraperitoneal) injection in rats, an effect which seems mainly mediated through the neurotensin-1 receptor (Ntsr1). In obese as compared to normal-weight human subjects, postprandial plasma neurotensin concentration was reduced following a liquid fatty meal (Widen et al 1992, Reg peptides; Plasma concentrations of regulatory peptides in obesity following modified sham feeding (MSF) and a liquid test meal), suggesting regulation of neurotensin secretion is disturbed in obesity. However, no large study has investigated if and how neurotensin is related to measures of obesity. Interestingly, P-NT significantly increases after gastric by-pass (Roux-en-Y), an operation shown to lead to normoglycemia in the majority of obese type 2 diabetes patients, but it is not known whether neurotensin is implicated in the development diabetes mellitus in general. Furthermore, the neurotensin system has been implicated in development of coronary artery disease and myocardial infarction as variation of the Ntsr3 (SORT1) gene is one of the strongest common coronary artery diseases susceptibility genes known in humans.
The mechanistic link between obesity and cancer is largely unknown, however, one of the dominating theories is that excess of fat deposits leads to increased peripheral aromatization of androgens and thus elevated circulating estrogen levels. In addition, one of the hallmarks of obesity, hyperinsulinemia, has been shown to inhibit hepatic production of Sexual Hormone Binding Globulin (SHBG), thus increasing bioavailable levels of both estrogens and androgens suggesting ways through which obesity may increase the risk of common forms of sex-hormone driven forms of cancer such as breast and prostate cancer. Interestingly, both neurotensin and Ntsr1 expression is common in malignant ductal breast cancer tumors and experimentally pharmacological blockade or RNA silencing of the NTSR1 reduces tumour growth in mice.
The level of expression of neurotensin receptor 1 (NTSR1) in breast cancer cells has been used for determining the prognosis of a subject suffering from breast cancer (US 2011/0305633). Further, it is stated in by the same authors that no clear correlation has been described today between circulating neurotensin and the stages of pancreas, prostate, or medullar thyroid tumors probably due to rapid clearance by the liver. Interestingly, it was found that in a series of 51 patients with invasive ductal breast cancer 91% of all tumors were positive for neurotensin receptor 1 (NTSR1) but only 31% of all tumors were positive for neurotensin in said tissue (Souaze et. Al. Cancer Research 2006; 66: (12) pages 6243-6249.
There is some evidence that neurotensin and neurotensin receptors participate in cancer growth, in particular in lung cancer, pancreatic cancer and colon cancer (Carraway et al.; Peptides 27 (2006) 2445-2460). It has been reported that levels of NT in sera of patients with pancreatic cancer were significantly enhanced (Picheon et al, Anticancer Research 1999; 19; 1445-50). Interestingly this group found that NT levels fell with progression of the disease for both prostate an pancreatic cancer. In contrast, thereto, Meggiato et al; Tumori 1996; 82; 592-5; found that plasma levels of NT were normal in pancreatic cancer but elevated in case where pancreatitis was diagnosed.
The use of vasoactive peptides for prediction of cancer risks in males has been reported by belting et al, Cancer, Epidemiology, Biomarkes & Prevention. MR-pro-ANP, MR-pro-ADM and copeptin was measured in the fasting plasma from participants of the Malmö Diet and Cancer Study that were free from cancer prior to the baseline exam in 1991 to 1994 (1768 males and 2293 females) The Authors stated that among females, there was no relationship between biomarkers and cancer incidence.
CRP and Pro-BNP are known predictors of cardiovascular events in the population (Melander et. Al, JAMA. 2009; 302(1):49-57). There is now information about any gender difference of the predictive power CRP and Pro-BNP for CVD endpoints.
A subject of the present invention was to investigate the prognostic and diagnostic power of NT for predicting the risk of getting a cardiovascular event in a subject to address this issue, we measured stable fragments of pro-neurotensin in fasting plasma in said Swedish prospective cohort study (Malmö Diet and Cancer Study, see Melander et. al, JAMA. 2009; 302(1):49-57) and related baseline level of this biomarker to cardiovascular events during 15 years of follow-up.
Surprisingly, it has been shown that neurotensin is a powerful and highly significant biomarker for woman for predicting the risk of getting a cardiovascular event
Thus, subject of the present invention is a method for predicting the risk of getting a cardiovascular event in a female subject comprising:
In a specific embodiment of the invention said cardiovascular event is an acute cardiovascular event selected from the group comprising myocardial infarction, stroke, acute heart failure and cardiovascular death related to myocardial infarction, stroke or acute heart failure.
In a specific embodiment of the invention subject matter of the invention is a method for predicting the risk of getting a cardiovascular event in a female subject comprising:
And wherein said cardiovascular event is an acute cardiovascular event selected from the group comprising myocardial infarction, stroke, acute heart failure and cardiovascular death related to myocardial infarction, stroke or acute heart failure.
The level of pro-neurotensin 1-117 or fragments thereof of at least 5 amino acids or pro-neurotensin 1-117 comprising peptides in a bodily fluid obtained from said female subject that is predictive for the risk of getting a cardiovascular event in said female subject may is released from the small intestine. The release of neurotensin from the small intestine is stimulated by food intake, especially by fat, and is known to regulate gastrointestinal motility and pancreatic and biliary secretion. Pro-neurotensin 1-117 and fragments thereof or pro-neurotensin 1-117 comprising peptides are used as a surrogate marker for the released neurotensin as neurotensin and pro-neurotensin 1-117 and fragments thereof or pro-neurotensin 1-117 comprising peptides are released in equimolar amounts from pro-neurotensin.
It is the surprising finding of the present invention that the peripheral secretion of neurotensin/pro-neurotensin 1-117 or fragments thereof of at least 5 amino acids or pro-neurotensin 1-117 comprising peptides is indicative for the susceptibility of a female subject to get a cardiovascular event. Thus, dietary measures as reduction of fat uptake may lower said risk in said female subject.
Data obtained in present study revealed also a correlation between the risk of getting a cardiovascular event in male subjects with the level of pro-neurotensin or fragments thereof of at least 5 amino acids in a bodily fluid obtained from said male subject; this correlation however, was not that significant for the present data. Thus, we assume that there is a value for the method according to the invention also for male subjects but the observed effect was not that strong for males in the present study.
The term “subject” as used herein refers to a living human or non-human organism. Preferably herein the subject is a human subject.
The correlation between the level of pro-neurotensin or fragments thereof of at least 5 amino acids or pro-neurotensin 1-117 comprising peptides in a bodily fluid obtained from said female subject and the risk of getting a cardiovascular event is continuous, i.e. the higher the level the higher the risk. This can be seen from the data e.g. in Table 17. In comparison to the first quartile the second, third and forth quartile exhibits higher Hazard Risks respectively.
For the sake of practicability the person skilled in the art may use threshold(s).
Thus, the term “elevated level” may mean a level above a threshold level.
In one embodiment of the invention the level of pro-neurotensin or fragments thereof of at least 5 amino acids or pro-neurotensin 1-117 comprising peptides in a bodily fluid is the fasting level of pro-neurotensin or fragments thereof of at least 5 amino acid or pro-neurotensin 1-117 comprising peptides. Fasting level means no food uptake 12 h prior blood sampling.
A bodily fluid may be selected from the group comprising blood, serum, plasma, urine, cerebro spinal liquid (csf), and saliva.
In one embodiment of a method according to the present invention said female subject has no history of diagnosis of an acute cardiovascular event at the time the sample of bodily fluid is taken from said female subject.
In another embodiment of a method according to the present invention said female subject has been diagnosed as having at a cardiovascular disease or diabetes wherein at the time the sample of bodily fluid is taken from said female subject.
In a specific embodiment said cardiovascular disease at the time the sample of bodily fluid is taken from said female subject may be selected from the group comprising heart failure, atherosclerosis, and hypertension.
The present data suggest a strong correlation between the level of pro-neurotensin or fragments thereof with a cardiovascular event in woman with no prevalent diabetes, no prevalent breast cancer and no prevalent cardiovascular disease.
The present data also suggest a strong correlation between the level of pro-neurotensin or fragments thereof with a cardiovascular event in hypertensive woman, which is a common high-risk group for cardiovascular disease.
Furthermore, the present data also suggest a strong correlation between the level of pro-neurotensin or fragments thereof with a cardiovascular event in normotensive woman. Further, the present data suggest a strong correlation between the level of pro-neurotensin or fragments thereof with a cardiovascular event in diabetic woman.
In another specific embodiment of the invention at the time the sample of bodily fluid is taken from said female subject, said female subject has been diagnosed as having at diabetes Typ II. In a specific embodiment of the invention the prediction of a first adverse event in a subject or the identification of a subject having an enhanced risk for getting a first adverse event is improved by additionally determining and using the level of at least one further marker selected from the group comprising: CRP, LpLA2, Cystatin C and natriuretic peptides of the A- and the B-type as well as their precursors and fragments thereof including ANP, proANP, NT-proANP, MR-proANP, BNP, proBNP, NT-proBNP triglycerides, HDL cholesterol or subfractions thereof, LDL cholesterol or subfractions thereof, GDF15, ST2.
In a very specific embodiment of the method according to the invention in addition to the level of pro-neurotensin or fragments thereof of at least 5 amino acids or pro-neurotensin 1-117 comprising peptides the level of the following marker is determined and used: proBNP or fragments or precursors thereof having at least 12 amino acids and/or CRP.
In another specific embodiment of the invention additionally at least one clinical parameter is determined selected from the group comprising: age, systolic blood pressure, diastolic blood pressure, antihypertensive treatment, body mass index, presence of diabetes mellitus, current smoking.
Cardiovascular events (CVD) were defined as coronary events or fatal or nonfatal stroke. Events were identified through linkage of the 10-digit personal identification number of each Swedish citizen with 3 registries: the Swedish Hospital Discharge Register, the Swedish Cause of Death Register, and the Stroke in Malmö register. Myocardial infarction was defined on the basis of International Classification of Diseases, 9th and 10th revisions (ICD-9 and ICD-10) codes 410 and I21, respectively. Fatal or nonfatal stroke was defined using codes 430, 431, 434, and 436 (ICD-9) and I60, I61, I63, and I64 (ICD-10).
The definition of diabetes is as follows: a history of physician diagnosis or being on anti-diabetic medication or having a fasting whole blood glucose >/=6.1 mmol/l (note this is =7.0 mmol/l in plasma) at the baseline examination.
The definition of normotensive/high blood pressure (HBP) is as follows:
HBP: Systolic BP>/=140 mmHg Diastolic BP>/=90 mmHg or being on antihypertensive medications. Subjects having normal blood pressure (BP) are all other subjects, i.e subjects with Systolic BP<140 mmHg or Diastolic BP<90 mmHg or not being on antihypertensive medications.
Fragments of pro-neurotensin that may be determined in a bodily fluid may be e.g. selected from the group of the following fragments:
In a more specific embodiment of the method according to the present invention the level of pro-neurotensin 1-117 is determined.
In a specific embodiment the level of pro-neurotensin is measured with an immunoassay. More specifically an immunoassay is used as described in Ernst et al. Peptides 27 (2006) 1787-1793. An immunoassay that may be useful for determining the level of pro-neurotensin or fragments thereof of at least 5 amino acids may comprise the steps as outlined in Example 2. All thresholds and values have to be seen in correlation to the test and the calibration used according to Example 2. A person skilled in the art may know that the absolute value of a threshold might be influenced by the calibration used. This means that all values and thresholds given herein are to be understood in context of the calibration used in herein (Example 2). A human P-NT-calibrator is available by ICI-Diagnostics, Berlin, Germany. Alternatively, the assay may also be calibrated by synthetic or recombinant P-NT 1-117 or fragments thereof (see also Ernst et. al, 2006).
The threshold for determining the risk of getting a cardiovascular event in a female subject according to the methods of the present invention is above 78 pmol/l PNT, preferred 100 pmol/l, more preferred 150 pmol/l. In a specific embodiment said threshold is about 100 pmol/l. These thresholds are related to the above mentioned calibration method. A P-NT value above said threshold means that the subject has an enhanced risk of getting a cardiovascular event.
In a specific embodiment of the method according to the invention the prediction of the risk of the subject for contracting cardiovascular events is improved by additionally determining and using the level of at least one laboratory parameter or further marker selected from the group comprising fasting blood or plasma glucose, triglycerides, HDL cholesterol or subfractions thereof, LDL cholesterol or subfractions thereof, Cystatin C, Insulin, CRP, vasopressin or its precursors or fragments thereof and BNP or its precursors or fragments thereof.
In a specific embodiment of the method according to the invention additionally at least one clinical parameter is determined selected from the group comprising age, gender, systolic blood pressure, diastolic blood pressure, antihypertensive treatment (AHT), body mass index, waist circumference, waist-hip-ratio, current smoker, diabetes heredity and previous cardiovascular disease (CVD).
Subject matter of the present invention is further a method for predicting the risk of getting a cardiovascular event in a subject or identifying a subject having an enhanced risk for getting a cardiovascular event according to the invention, wherein the level of pro-neurotensin or fragments thereof of at least 5 amino acids either alone or in conjunction with other prognostically useful laboratory or clinical parameters is used for the prediction of a subject's risk for getting a cardiovascular event by a method which may be selected from the following alternatives:
In one embodiment of the method according to the invention said a method is performed more than once in order to monitor the risk of getting a cardiovascular event in a female subject.
In another embodiment of the method according to the invention said monitoring is performed in order to evaluate the response of said female subject to preventive and/or therapeutic measures taken.
In another embodiment of the method according to the in order invention the method is used to stratify said female subjects into risk groups.
Also encompassed by the present invention is a point-of-care device for performing a method according to the invention.
Also encompassed by the present invention is an assay and/or kit for performing a method according to the invention.
Subject matter of the invention is also a binder to neurotensin or to a neurotensin receptor, for the use in prevention or therapy of a cardiovascular event in a female subject.
In one embodiment of the invention the binder reduces the bioactivity of neurotensin to 70% or less.
According to the invention the binder to neurotensin is selected from the group consisting of antibodies e.g. IgG, a typical full-length immunoglobulin, or antibody fragments containing at least the F-variable domain of heavy and/or light chain as e.g. chemically coupled antibodies (fragment antigen binding) including but not limited to Fab-fragments including Fab minibodies, single chain Fab antibody, monovalent Fab antibody with epitope tags, e.g. Fab-V5Sx2; bivalent Fab (mini-antibody) dimerized with the CH3 domain; bivalent Fab or multivalent Fab, e.g. formed via multimerization with the aid of a heterologous domain, e.g. via dimerization of dHLX domains,e.g. Fab-dHLX-FSx2; F(ab′)2-fragments, scFv-fragments, multimerized multivalent or/and multispecific scFv-fragments, bivalent and/or bispecific diabodies, BITE® (bispecific T-cell engager), trifunetional antibodies, polyvalent antibodies, e.g. from a different class than G; single-domain antibodies, e.g. nanobodies derived from camelid or fish immunoglobulines.
According to the invention the binder to a neurotensin receptor is selected from the group consisting of antibodies e.g. IgG, a typical full-length immunoglobulin, or antibody fragments containing at least the F-variable domain of heavy and/or light chain as e.g. chemically coupled antibodies (fragment antigen binding) including but not limited to Fab-fragments including Fab minibodies, single chain Fab antibody, monovalent Fab antibody with epitope tags, e.g. Fab-V5Sx2; bivalent Fab (mini-antibody) dimerized with the CH3 domain; bivalent Fab or multivalent Fab, e.g. formed via multimerization with the aid of a heterologous domain, e.g. via dimerization of dHLX domains,e.g. Fab-dHLX-FSx2; F(ab′)2-fragments, say-fragments, multimerized multivalent or/and multispecific scFv-fragments, bivalent and/or bispecific diabodies, BITE® (bispecific T-cell engager), trifunctional antibodies, polyvalent antibodies, e.g. from a different class than G; single-domain antibodies, e.g. nanobodies derived from camelid or fish immunoglobulines, or a peptide antagonist e.g. [D-Trp11]-Neurotensin, [Tyr(Me)1′]-Neurotensin (e.g. described by Quiron et al.), or a non-peptide antagonist, e.g. Levocabastine, SR-48692 (NTS1 selective), SR-142948 (unselective), SR-142948A, CP 96345, [3H]SR-48692, SR 48692, SR-48527 and SR-49711, or a binder scaffold e.g. tetranectin-based non-Ig scaffolds (e.g. described in US 2010/0028995), fibronectin scaffolds (e.g. described in EP 1266 025; lipocalin-based scaffolds ((e.g. described in WO 2011/154420); ubiquitin scaffolds (e.g. described in WO 2011/073214), transferring scaffolds (e.g. described in US 2004/0023334), protein A scaffolds (e.g. described in EP 2231860), ankyrin repeat based scaffolds (e.g. described in WO 2010/060748), microproteins preferably microproteins fanning a cystine knot) scaffolds (e.g. described in EP 2314308), Fyn SH3 domain based scaffolds (e.g. described in WO 2011/023685) EGFR-A-domain based scaffolds (e.g. described in WO 2005/040229) and Kunitz domain based scaffolds (e.g. described in EP 1941867).
Peptides for immunization were synthesized OPT Technologies, Berlin, Germany) with an additional N-terminal Cystein residue for conjugation of the peptides to Bovine Serum Albumin (BSA). The peptides were covalently linked to BSA by using Sulfo-SMCC (Perbio-science, Bonn, Germany). The coupling procedure was performed according to the manual of Perbio.
The antibodies were generated according to the following method:
A BALB/c mouse were immunized with 100 μg Peptide-BSA-Conjugate at day 0 and 14 (emulsified in 100 μl complete Freund's adjuvant) and 50 μg at day 21 and 28 (in 100 incomplete Freund's adjuvant). Three days before the fusion experiment was performed, the animal received 50 μg of the conjugate dissolved in 100 μl saline, given as one intraperitoneal and one intra venous injection.
Splenocytes from the immunized mouse and cells of the myeloma cell line SP2/0 were fused with 1 ml 50% polyethylene glycol for 30 s at 37° C. After washing, the cells were seeded in 96-well cell culture plates. Hybrid clones were selected by growing in HAT medium [RPMI 1640 culture medium supplemented with 20% fetal calf serum and HAT-Supplement]. After two weeks the HAT medium is replaced with HT Medium for three passages followed by returning to the normal cell culture medium.
The cell culture supernatants were primary screened for antigen specific IgG antibodies three weeks after fusion. The positive tested microcultures were transferred into 24-well plates for propagation. After retesting the selected cultures were cloned and recloned using the limiting-dilution technique and the isotypes were determined.
(Lane, R. D. “A short-duration polyethylene glycol fusiontechnique for increasing production of monoclonal antibody-secreting hybridomas”, J. Immunol. Meth. 81: 223-228; (1985), Ziegler, B. et al. “Glutamate decarboxylase (GAD) is not detectable on the surface of rat islet cells examined by cytofluorometry and complement-dependent antibody-mediated cytotoxicity of monoclonal GAD antibodies”, Horm. Metab. Res. 28: 11-15, (1996)).
Antibodies were produced via standard antibody production methods (Marx et al, Monoclonal Antibody Production, ATLA 25, 121, 1997,) and purified via Protein A-chromatography. The antibody purities were >95% based on SDS gel electrophoresis analysis.
The technology used was a sandwich coated tube luminescence immunoassay, based on Akridinium ester labelling.
Labelled compound (tracer): 100 ug (100 ul) LA (1 mg/ml in PBS, pH 7.4, was mixed with 10 ul Akridinium NHS-ester (1 mg/ml in acetonitrile, InVent GmbH, Germany) (EP 0353971) and incubated for 20 min at room temperature. Labelled LA was purified by Gel-filtration HPLC on Bio-Sil SEC 400-5 (Bio-Rad Laboratories, Inc., USA) The purified LA was diluted in (300 mmol/l potassiumphosphate, 100 mmol/l NaCl, 10 mmol/l Na-EDTA, 5 g/l Bovine Serum Albumin, pH 7.0). The final concentration was approx. 800.000 relative light units (RLU) of labelled compound (approx. 20 ng labeled antibody) per 200 μl. Akridiniumester chemiluminescence was measured by using an AutoLumat LB 953 (Berthold Technologies GmbH & Co. KG, ( ).
Solid phase: Polystyrene tubes (Greiner Bio-One International AG, Austria) were coated (18 h at room temperature) with SPA ((1.5 μg SPA/0.3 ml 100 mmol/l NaCl, 50 mmol/l tris/HCI, pH 7.8). After blocking with 5% bovine serum albumine, the tubes were washed with PBS, pH 7.4 and vakuum dried.
The assay was calibrated, using dilutions of P-NT-containing human serum. A pool of human sera with high P-NT-immunoreactivity (InVent Diagostika, Hennigsdorf, Germany) was diluted with horse serum (Biochrom AG, Deutschland) (assay standards).
The standards were calibrated by use of the human P-NT-calibrator (ICI-Diagnostics, Berlin, Germany). Alternatively, the assay may be calibrated by synthetic or recombinant P-NT 1-117 or fragments thereof (see also Ernst et. al, 2006).
50 μl of sample (or calibrator) was pipetted into SPA coated tubes, after adding labelled LA (200 μl), the tubes were incubated for 16-22 h at 18-25° C. Unbound tracer was removed by washing 5 times (each 1 ml) with washing solution (20 mM PBS, pH 7.4, 0.1% Triton X-100).
Tube-bound LA was measured by using the LB 953
We measured P-NT in fasting plasma from 4362 participants of the population based Malmö Diet and Cancer Study baseline exam in 1991-1994 (men age 58±6 years and 59% females). We used multivariable adjusted (all traditional cardiovascular risk factors, diabetes risk factors and in analyses of cancer also heredity for cancer) Cox proportional hazards models to relate baseline P-NT (hazard ratio per each standard deviation increase of log-transformed P-NT) to the time to the first event of each of the studied endpoints during a median follow-up time of more than 12 years. Endpoints were retrieved through the Swedish National Hospital Discharge Registry, the Swedish Myocardial Infarction Registry, the Stroke in Malmö Registry and the Swedish Cancer Registry. Retrieval of endpoints through these registries has been validated and found to be accurate.
The baseline characteristics of the study population are shown in Table 1. Women had slightly but significantly higher P-NT [median (interquartile range)] than men [109 (79-150) versus 99 (71-144) pmol/l] (P<0.001). The cross sectional relationship between P-NT and measures of obesity, cardiovascular risk factors and diabetes risk factors was generally weak with the strongest correlation being that with fasting insulin concentration in both gender (Supplementary Table 1). In a linear regression model with backward elimination and a retention P-value of 0.10, significant independent determinants of P-NT were smoking and fasting concentrations of insulin, glucose, and HDL (all positive) in women and smoking and fasting concentrations of insulin and HDL (positively related) and age and LDL (negatively related) in men (Table 2).
P-NT and Prediction of Cardiovascular Disease, Cardiovascular Mortality and all-Cause Mortality
Among subjects without cardiovascular disease prior to the baseline exam, 519 suffered a first cardiovascular disease event during 14.4±4.4 years of follow-up. After full adjustment far baseline levels of cardiovascular risk factors (age, gender, antihypertensive treatment, systolic blood pressure, body mass index, diabetes mellitus, HDL, LDL and smoking) each SD increase of P-NT was associated with 17% increased risk of incident cardiovascular disease (Table 3). There was a strong interaction between P-NT and female gender (P<0.001) and gender stratified analyses revealed that each SD increase of baseline P-NT was strongly associated with a 33% increased risk of incident cardiovascular disease in women, whereas there was no significant relationship among men (Table 3). Quartile analyses revealed that the top versus the bottom quartile was associated with a 37% increased risk for incident cardiovascular disease in the total population and 65% increased risk in women (Table 3).
Additional adjustment for fasting insulin concentration, i.e. the strongest cross-sectional correlate of P-NT, did not affect the results (not shown).
We then assessed the relationship between total and cardiovascular mortality in the entire population as well as in men and women separately in models fully adjusted for all cardiovascular risk factors. Each SD increase of P-NT was associated with a significant 8% increase in the risk of all-cause mortality in the total population and a 13% risk of all-cause mortality among women whereas there was no such increased risk related to P-NT in men (Table 3). The excess risk of death in appeared to be mainly accounted for by cardiovascular deaths with 29% per SD increase in the risk of cardiovascular death in the total population and 50% excess risk in females. Female subjects belonging to the top as compared to the bottom quartile of P-NT had a more than 2-fold increased risk of suffering cardiovascular death (Table 3).
Multivariate Cox proportional Hazards models for baseline P-NT versus incidence of cardiovascular disease, all-cause- and cardiovascular mortality
In order to compare the statistical strength and the effect estimates on the studied endpoints between P-NT and established plasma biomarkers, we entered P-NT simultaneously with N-BNP and CRP in fully adjusted models (CRP and N-BNP was measured as described by Melander et al., JAMA. 2009; 302(1):49-57). As seen below, P-NT performed equally well as N-BNP and CRP for most endpoints in the total population and in females P-NT performed clearly better than N-BNP and CRP (CRP alone was not significant in females). Combining (see Melander et al., JAMA. 2009; 302(1):49-57) N-BNP and P-NT further improved the predictive power for CVD in females from 33% HR per 1 SD (P-NT alone to 34.8% per 1 SD (p<0.001) (combination of P-NT and N-BNP.
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The prediction of CVD-events by baseline P-NT was given for the complete observation period.
Using the same variables in the equation, we investigated different subgroups for prediction of CVD, mortality, CVD mortality. Subjects with precious CVD-events were excluded.
Prediction of CVD events was only related to females. The predictive power of P-NT was similar in completely healthy and in high risk subgroups like diabetic women or HBP women.
Prediction of CVD mortality by P-NT was strong in women and not significant in male. The predictive power of P-NT was given in healthy women and in high risk women (diabetic or HBP).
Reclassification of Woman into Risk Groups
We calculated model c-statistics and reclassification across 10-year predicted risk categories for the different events (<5%, >=5-10%, >=10-20% and >=20%, respectively) with Net Reclassification Improvement (NRI) for models with and without P-NT.30-32 All analyses were performed with Stata software version 11 (StataCorp, College Station, Tex.). A two-sided P-value of <0.05 was considered statistically significant.
For cardiovascular mortality, there was a borderline significant increase of the over-all NRI of 11%. P-NT correctly reclassified 19% of females who actually suffered cardiovascular death to a higher category of risk but only reclassified 5% of women who did not suffer cardiovascular death to a lower category of risk (Table 5). Among women at intermediate (10-20%) 10-year risk, i.e. the group in which biomarker support has been suggested to be particularly important for clinical decision making regarding initiation of primary preventive therapy (and reclassification thus referred to as “clinical NRI”), 38 addition of P-NT to traditional cardiovascular risk factors resulted in a significant clinical NRI of 40% for cardiovascular mortality, with reclassification of 21% women who died a cardiovascular death to a higher category of risk and 30% of women who did not suffer cardiovascular death to a lower category of risk.
| Number | Date | Country | Kind |
|---|---|---|---|
| 12158678.8 | Mar 2012 | EP | regional |
| 12165057.6 | Apr 2012 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2013/054799 | 3/8/2013 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 61608376 | Mar 2012 | US |
