Systemic inflammation induced by exacerbation of COPD or pneumonia in patients with COPD induces cardiac troponin elevation

Abstract

Background Troponin is a biomarker of myocardial injury. In chronic obstructive pulmonary disease (COPD), troponin is an important determinant of mortality after acute exacerbation. Whether acute exacerbation of COPD (AECOPD) causes troponin elevation is not known. Here, we investigated whether troponin is increased in AECOPD compared to stable COPD.Methods We included 320 patients with COPD in the stable state and 63 random individuals from Akershus University hospital’s catchment area. All participants were ≥40 years old (mean 65·1 years, SD 7·6) and 176 (46%) were females. The geometric mean of high-sensitivity cardiac troponin T (hs-cTnT) was 6·9 ng/L (geometric-SD 2·6). They were followed regarding hospital admission for the subsequent 5 years.Results During the 5-year follow-up, we noted 474 hospitalisations: Totally, 150 and 80 admissions were due to AECOPD or pneumonia, respectively. The geometric mean ratio with geometric SE (GSE) between cTnT at admission and stable state in AECOPD and pneumonia was 1·27 (GSE=1.11, p=0·023) and 1·28 (GSE=1.14, p=0·054), respectively. After inclusion of blood leucocyte count and C reactive protein at hospitalisation, these ratios attenuated to zero. However, we estimated an indirect of AECOPD and pneumonia on the ratio between hs-cTnT at admission and the stable state to 1·16 (p=0·022) and 1·22 (p=0·008), representing 91% (95% CI 82% to 100%) and 95% (95% CI 83% to 100%) of the total effects, respectively.Conclusion AECOPD and pneumonia in patients with COPD is associated with higher cTnT levels. This association appears to be mediated by systemic inflammation.