Determinants of cardiac troponin T elevation in COPD exacerbation – a cross-sectional study

BACKGROUND Cardiac Troponin T (cTnT) elevation during exacerbations of chronic obstructive pulmonary disease (COPD) is associated with increased mortality the first year after hospital discharge. The factors associated with cTnT elevation in COPD are not known. METHODS From our hospital's database, all patients admitted with COPD exacerbation in 2000-03 were identified. 441 had measurement of cTnT performed. Levels of cTnT > or = 0.04 microg/l were considered elevated. Clinical and historical data were retrieved from patient records, hospital and laboratory databases. Odds ratios for cTnT elevation were calculated using logistic regression. RESULTS 120 patients (27%) had elevated cTnT levels. The covariates independently associated with elevated cTnT were increasing neutrophil count, creatinine concentration, heart rate and Cardiac Infarction Injury Score (CIIS), and decreasing hemoglobin concentration. The adjusted odds ratios (95% confidence intervals in parentheses) for cTnT elevation were 1.52 (1.20-1.94) for a 5 x 106/ml increase in neutrophils, 1.21 (1.12-1.32) for a 10 micromol/l increase in creatinine, 0.80 (0.69-0.92) for a 1 mg/dl increase in hemoglobin, 1.24 (1.09-1.42) for a 10 beats/minute increase in heart rate and 1.44 (1.15-1.82) for a 10 point increase in CIIS. CONCLUSION Multiple factors are associated with cTnT elevation, probably reflecting the wide panorama of comorbid conditions typically seen in COPD. The positive association between neutrophils and cTnT elevation is compatible with the concept that an exaggerated inflammatory response in COPD exacerbation may predispose for myocardial injury.