High-Sensitivity Cardiac Troponin I for Risk Stratification in Older Adults

BACKGROUND/OBJECTIVES Traditional cardiovascular risk factors are less predictive in older age. High-sensitivity cardiac troponin I (hs-cTnI) is a marker of subclinical cardiomyocyte damage associated with cardiovascular risk in middle-aged adults. We hypothesized hs-cTnI would be indicative of mortality and cardiovascular risk beyond traditional cardiovascular risk factors in older adults and may be more discriminatory compared to hs-troponin T (hs-cTnT). DESIGN Prospective cohort study. SETTING Population-based Atherosclerosis Risk in Communities (ARIC) Study. PARTICIPANTS We included 5,876 ARIC participants at Visit 5 (2011-2013). OUTCOMES AND MEASURES We used Cox regression for the association of hs-cTnI categories (women: <4, 4-<10, >= 10 ng/ml; men: <6, 6-<12, >= 12 ng/ml, prevalent cardiovascular disease (CVD)) with mortality and incident CVD (atherosclerotic CVD [ASCVD]: coronary heart disease or stroke, or heart failure). RESULTS Participants were ages 66 to 90, 23% black, 42% male, and 24% had prevalent CVD. There were 1,053 (321 CVD) deaths (median follow-up 6.3 years). Participants with elevated hs-cTnI and no CVD (7% of participants) had mortality risk similar to those with a history of CVD (55.6 vs 55.7 deaths/1,000 person-years, P = .99). After adjustment, elevated hs-cTnI and no CVD (hazard ratio (HR) = 2.38, 95% confidence interval (CI) = 1.85-3.06) and prevalent CVD (HR = 2.21, 95% CI = 1.90-2.57) remained associated with mortality, compared to low hs-cTnI and no CVD. Elevated hs-cTnI was independently associated with incident CVD (HR = 3.41, 95% CI = 2.58-4.51), ASCVD (HR = 2.02, 95% CI = 1.36-2.98), and heart failure (HR = 6.16, 95% CI = 4.24-8.95). The addition of hs-cTnI significantly improved C-statistics for all outcomes and added greater discrimination than hs-cTnT for cardiovascular mortality and incident heart failure. CONCLUSIONS Hs-cTnI improves mortality and CVD risk stratification in older adults beyond traditional risk factors and improved model discrimination more than hs-cTnT for certain outcomes. Elevated hs-cTnI without CVD identifies a high-risk group with comparable mortality risk as those with a history of clinical CVD.

Automated summary

In older adults, high-sensitivity cardiac troponin I (hs-cTnI) is more predictive of mortality and cardiovascular risk compared to traditional risk factors, and provides better discrimination abilities. Its elevation without clinical cardiovascular disease identifies a high-risk group with comparable mortality risks to those with a history of CVD.