Cardiac troponin I levels measured with a high-sensitive assay increase over time and are strong predictors of mortality in an elderly population

Abstract

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.