Predictive and prognostic value of different cardiac troponin assays: a nationwide register-based cohort study

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.

Serial troponin-I and long-term outcomes in subjects with suspected acute coronary syndrome

AIMS

It is unclear how serial high-sensitivity troponin-I (hsTnI) concentrations affect long-term prognosis in individuals with suspected acute coronary syndrome (ACS).

METHODS AND RESULTS

Subjects who underwent two hsTnI measurements (Siemens TnI Flex® Reagent) separated by 1-7 h, during a first-time hospitalization for myocardial infarction, unstable angina, observation for suspected myocardial infarction, or chest pain from 2012 through 2019, were identified through Danish national registries. Individuals were stratified per their hsTnI concentration pattern (normal, rising, persistently elevated, or falling) and the magnitude of hsTnI concentration change (<20%, >20-50%, or >50% in either direction). We calculated absolute and relative mortality risks standardized to the distributions of risk factors for the entire study population. A total of 20 609 individuals were included of whom 2.3% had died at 30 days, and an additional 4.7% had died at 365 days. The standardized risk of death was highest among persons with a persistently elevated hsTnI concentration (0-30 days: 8.0%, 31-365 days: 11.1%) and lowest among those with two normal hsTnI concentrations (0-30 days: 0.5%, 31-365 days: 2.6%). In neither case did relative hsTnI concentration changes between measurements clearly affect mortality risk. Among persons with a rising hsTnI concentration pattern, 30-day mortality was higher in subjects with a >50% rise compared with those with a less pronounced rise (2.2% vs. <0.1%).

CONCLUSION

Among individuals with suspected ACS, those with a persistently elevated hsTnI concentration consistently had the highest risk of death. In subjects with two normal hsTnI concentrations, mortality was very low and not affected by the magnitude of change between measurements.