C-reactive protein and B-type natriuretic peptide yield either a non-significant or a modest incremental value to traditional risk factors in predicting long-term overall mortality in older adults

• Published in: PloS one 2013-09, Vol.8 (9), p.e75809-e75809
• Main Authors: Beleigoli, Alline M, Boersma, Eric, Diniz, Maria de Fátima H, Vidigal, Pedro G, Lima-Costa, Maria Fernanda, Ribeiro, Antonio L
• Format: Article
• Language: English
• Subjects: Adults; Age Factors; Aged; Aging; Biomarkers; Biomarkers - blood; Biomarkers - metabolism; Brain natriuretic peptide; C-reactive protein; C-Reactive Protein - metabolism; Cause of Death; Death; Female; Geriatrics; Health risk assessment; Humans; Male; Mathematical models; Middle Aged; Models, Statistical; Mortality; Natriuretic Peptide, Brain - blood; Natriuretic Peptide, Brain - metabolism; Older people; Patient Outcome Assessment; Prognosis; Reclassification; Risk analysis; Risk Factors; Statistical analysis; Survival Analysis
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0075809

New biomarkers may aid in preventive and end-of-life decisions in older adults if they enhance the prognostic ability of traditional risk factors. We investigated whether C-reactive protein (CRP) and/or B-type natriuretic peptide (BNP) improve the ability to predict overall mortality among the elderly of the Bambuí, Brazil Study of Aging when added to traditional risk factors. From 1997 to 2007, 1,470 community-dwelling individuals (≥60 years) were followed-up. Death was ascertained by continuous verification of death certificates. We calculated hazard ratios per 1 standard deviation change (HR) of death for traditional risk factors only (old model), and traditional risk factors plus CRP and/or BNP (new models) and assessed calibration of the models. Subsequently, we compared c-statistic of each of the new models to the old one, and calculated integrated discriminative improvement (IDI) and net reclassification improvement (NRI). 544 (37.0%) participants died in a mean follow-up time of 9.0 years. CRP (HR 1.28, 95% CI 1.17-1.40), BNP (HR 1.31 95% CI 1.19-1.45), and CRP plus BNP (HR 1.26, 95% CI 1.15-1.38, and HR 1.29, 95% CI 1.16-1.42, respectively) were independent determinants of mortality. All models were well-calibrated. Discrimination was similar among the old (c-statistic 0.78 [0.78-0.81]) and new models (p=0.43 for CRP; p=0.57 for BNP; and p=0.31 for CRP plus BNP). Compared to the old model, CRP, BNP, and CRP plus BNP models led to an IDI of 0.009 (p