Troponin elevation during infection is associated with increased acute and long-term mortality

Abstract Introduction Troponin elevation in patients with sepsis is associated with increased in-hospital mortality in small studies of patients requiring intensive care, and more recently in patients suffering COVID-19. Previous meta-analyses(1) have found that a raised troponin during sepsis is associated with increased mortality, but the studies were typically small (median 40 patients leading to meta-analyses of around 1000 patients), studied only those with the most severe infections, and often excluded those with comorbidities, particularly coronary artery disease, which may be responsible for different causes of troponin elevation. Previous studies have also usually followed up patients to the point of discharge. Purpose We determined (i) whether an association between troponin elevation and mortality was seen in a large dataset without exclusion of comorbidities (ii) whether the association was seen in those with and without a diagnosis of coronary disease and (iii) whether troponin elevation was associated with mortality even in those who survived their initial illness. Methods A retrospective cohort study was carried out using the National Institute for Health Research Health Informatics Collaborative Cardiovascular dataset (2,3) of all consecutive patients who had a troponin measured at five hospitals between 2010 and 2017. We identified patients with an ICD-code indicating infection who had a troponin and c-reactive protein (CRP) measured. We compared the survival of those with a positive troponin with those with a negative troponin during and after hospital discharge. To assess the association of dichotomous troponin level (above upper limit of normal or not) with all-cause mortality, Cox proportional hazards regression modelling was used. A landmark analysis was performed in those who survived their hospital admission. Results Of 11,132 patients studied, 4,554 (42.4%) had a positive troponin. During median follow-up of 213 days there were 4,448 (40.0%) deaths. A positive troponin was associated with a 2.41-fold increase in mortality (95% CI 2.27-2.56) and was similar in patients known to have coronary disease (HR 2.15, 95% CI 1.87 to 2.46) and those without (HR 2.39, 95% CI 2.24 to 2.56). The association between troponin positivity and mortality was preserved in sepsis and different CRP strata.There was a trend towards higher levels of troponin being associated with higher mortality. A positive troponin continued to be associated with mortality in those surviving past discharge (HR 2.14, 95% CI 1.99 to 2.29) Conclusion In a large cohort of hospitalized patients suffering an infection, a raised troponin was associated with significantly increase mortality risk, regardless of known coronary status or severity of infection. A positive troponin during admission with infection continued to be associated with an ongoing increased risk of mortality, even in those surviving admission.