Background: The clinical relevance of minor elevations of cardiac troponin (cTn) in the general population remains uncertain. The objective of this systematic review was to examine the literature and evaluate the prevalence of raised cTn in asymptomatic, community populations and explore the strength of the relationship between cTn and cardiovascular mortality amongst those studied.
Methods: Studies were identified by searching Medline, Embase, CINAHL, EBM Reviews, Cochrane Library and using the "related citation" search tool in PubMed from inception through August 2014. Prospective cohort studies of asymptomatic individuals recruited from the community (age ≥ 18 years) that assessed the relationship between cTn levels and mortality or cardiovascular events were included.
Results: Twenty-one prospective studies involving 64,855 participants were identified. An elevated cTn measurement (>99th percentile) occurred in 5% of individuals and was associated with a tripling of risk of mortality (adjusted RR 3.07, 95% confidence interval [CI] 2.32-4.06) and cardiovascular mortality (adjusted RR 3.30, 95% CI 1.77-6.12). In studies including high sensitivity assays, cTn was detectable in 58% of individuals. A detectable cardiac troponin T (cTnT) was also associated with an increased risk of cardiovascular mortality (adjusted RR 1.32, 95% CI 1.10 - 1.59). The risk increased with increasing cTnT level.
Conclusions: Elevated troponin in asymptomatic individuals in the community is associated with a tripling of risk of all-cause and cardiovascular mortality. Cardiac troponin T (cTnT) is generally not measured in this group of patients, but may potentially have utility in predicting risk in this population. Further research is required to assess if this risk is modifiable with usual primary prevention treatments.