Cardiac Troponin Measurement in the Critically Ill: Potential for Guiding Clinical Management

BACKGROUND Elevated cardiac troponin (cTn) in the absence of acute coronary syndromes (ACS) is associated with increased mortality in critically ill patients. There are no evidence-based interventions that reduce mortality in this group. OBJECTIVES We performed a retrospective investigation of the Veterans Administration Inpatient Evaluation Center database to determine whether drugs used in ACS (β-blockers, aspirin, and statins) are associated with reduced mortality in critically ill patients. METHODS Thirty-day mortality was determined for non-ACS patients admitted to any Veterans Administration Intensive Care Unit between October 1, 2007, and September 30, 2008, adjusted for severity of illness. Troponin assay values were normalized across institutions. RESULTS Multivariate analyses for 30-day mortality showed an odds ratio (OR) of 1.82 for patients with high cTn (P < 0.0001, cTn > 10% coefficient of variation) and 1.18 for intermediate cTn (P = 0.0021, cTn between lowest limit detectable and 10% coefficient of variation) compared with patients with no elevation, adjusting for severity of illness (n = 19,979). Logistic regression models showed that patients with no or intermediate elevations of cTn taking statins within 24 hours of cTn measurement had a lower mortality than patients not taking statins (OR, 0.66; 95% confidence interval [95% CI], 0.53-0.82; P = 0.0003), whereas patients with high cTn had a lower mortality if they were taking β-blockers or aspirin within 24 hours of cTn measurement compared to patients not taking β-blockers or aspirin (β-blockers: OR, 0.80; 95% CI, 0.68-0.94; P = 0.0077; aspirin: OR, 0.81;95% CI, 0.69-0.96; P = 0.0134). CONCLUSIONS This retrospective study confirms an association between elevated troponin and outcomes in critically ill patients without ACS and identifies statins, β-blockers, and aspirin as potential outcome modifiers in a cTn-dependent manner.