Age-specific prognosis of acute and steady minor elevations in cardiac troponin among non-acute myocardial infarction inpatients: a large real-world cohort study

Background The upper reference limit of normal (ULN) of cardiac troponin (cTn) for older adults can be higher than for young adults, while the same ULN is used for both older and young adults in the current clinical practice. Methods In this multicentre longitudinal cohort study, non-acute myocardial infarction (non-AMI) inpatients with at least two cTn concentrations hospitalised between 2013 and 2022 in the Tianjin Health and Medical Data Platform were included. Multivariable Cox proportional hazards and landmark regression models were used to estimate the risk of in-hospital, 30-day and 1-year mortality in different cTn groups (normal, stable minor elevation (1–2×ULN with variation ≤20%), acute minor elevation (1–2×ULN with variation >20%) and apparent elevation (>2×ULN)). Results A total of 57 117 patients (mean age, 69.6 (13.6) years; 25 037 (43.8%) female) were included. Even minor elevation in cTn was associated with higher mortality risk. Compared with the normal cTn group, the adjusted HRs of in-hospital mortality for patients with steady minor elevation, acute minor elevation and >2× ULN in cTn were 1.70 (95% CI 1.25 to 2.33), 1.92 (95% CI 1.59 to 2.32) and 4.03 (95% CI 3.50 to 4.65), respectively. Similar trends were found for all-cause 30-day and 30-day to 1-year mortality. Among older adults, compared with the steady minor elevation group, patients with acute minor elevation in cTn had higher 30-day mortality risk (HR 1.30, 95% CI 1.02 to 1.65) but similar 30-day to 1-year mortality risk (HR 0.95, 95% CI 0.82 to 1.10), while among non-older adults, differences in short-term and 1-year mortality risks between the two groups were not statistically significant (p>0.05). Conclusions In non-AMI inpatients, including older adults, any stable or acute elevation in cTn, even minor, warrants attention. Further studies are needed to assess whether these patients can benefit from more aggressive treatment approaches.