Cardiac Troponin I Levels Measured With a High-Sensitive Assay Increase Over Time and Are Strong Predictors of Mortality in an Elderly Population

Objectives This study sought to assess changes in troponin levels, underlying conditions, and the prognostic implications in elderly subjects from the community. Background Cardiac troponin levels are often detectable in community dwellers when sensitive assays are applied. However, information on the course of troponin levels over time is limited. Methods Cardiac troponin I (cTnI) was measured by using a novel, high-sensitive assay in community dwellers aged 70 years from the Prospective Investigation of the Vasculature in Uppsala Seniors study. Measurements were performed at baseline (n = 1,004) and after 5 years (n = 814). Total follow-up was 8.0 years. Results cTnI levels were detectable in 968 (96.4%) subjects at baseline and independently predicted all-cause mortality (adjusted hazard ratio [HR]: 1.44 [95% confidence interval (CI): 1.18 to 1.77]) and cardiovascular mortality (adjusted HR: 1.66 [95% CI: 1.20 to 2.29]) when levels from baseline and 5-year follow-up were used as updated covariates. The integrated discrimination improvement of cTnI regarding all-cause mortality was 0.014 (p = 0.04), and the category-free net reclassification improvement was 0.231 (p = 0.02). Median cTnI levels increased by 45% between both measurements. The change in cTnI levels was significantly related to male sex (p = 0.02), body mass index (p = 0.01), high-density lipoprotein cholesterol (p = 0.005), N-terminal pro-B-type natriuretic peptide (p = 0.004), and left ventricular ejection fraction (p = 0.04), and it independently predicted all-cause mortality occurring after 5-year follow-up (adjusted HR: 1.97 [95% CI: 1.14 to 3.40]; p = 0.02). Conclusions Using a novel high-sensitive assay, cTnI levels could be determined in nearly all elderly study subjects. cTnI levels increased over time and were a strong marker of mortality risk. Our data suggest that cTnI might offer utility for clinical assessment of subjects in the general population. (c) 2013 by the American College of Cardiology Foundation