Implications of Age for the Diagnostic and Prognostic Value of Cardiac Troponin T and I

Background: The influence of age on cardiac troponin is unclear and may vary between cardiac troponin T (cTnT) and I (cTnI). We aimed to compare the impact of age on the diagnostic and prognostic utility of cTnT and cTnI. Methods: This Danish nationwide, register-based cohort study included patients with at least one cardiac troponin (cTn) measurement from 2009 through June 2022, stratified into decades of age. We used peak cTn concentration during admission, dichotomized as positive/negative and normalized to the 99th percentile. Receiver operating characteristics for myocardial infarction (MI) and logistic regression were used to estimate the odds ratio (OR) for mortality at 1 year. Results: We included 541 817 patients; median age 66 years (interquartile range [IQR] 51-77) and 256 545 (47%) female. A total of 40 359 (7.4%) had an MI, and 59 800 (14.1%) patients died within 1 year of admission. The predictive ability of both cTns for MI were highest for patients 30 to 50 years. This was most pronounced for cTnT, the specificity of which fell from 83% among patients 40 to 49 years to 4% for patients >= 90 years. The prognostic ability of both cTns for 1-year mortality declined with age. cTnT had stronger prognostic ability for all age-groups; OR for a positive cTnT 28.4 (95% CI, 20.1-41.0) compared with 9.4 (95% CI, 5.0-16.7) for cTnI among patients <30 years. Conclusions: The predictive and prognostic ability of cTnT and cTnI declined with age. cTnT had a low specificity for MI in elderly patients. However, cTnT was the strongest prognostic marker among all age groups.