Introduction Myocardial Infarction (MI) is a common comorbidity and cause of death in people with COPD, and COPD is associated with increased risk of death following acute MI.1,2 We aimed to: 1) compare levels of peak troponin following MI between people with and without COPD; and 2) investigate differences in the prognostic value of peak troponin between those with and without COPD.
Methods Patients from the Myocardial Ischaemic National Audit Project (MINAP) database who had linked Office of National Statistics (ONS) mortality data from 2003–2013 were included in the study. COPD was defined as the presence of obstructive airway disease and smoking history. We used linear regression to compare levels of peak troponin I and T between people with and without COPD followed by logistic regression to investigate the prognostic value of peak troponin level in predicting 180 day mortality separately for those with and without COPD. All models were adjusted for age, sex, smoking, peripheral vascular disease, cerebrovascular disease, chronic renal failure and previous angina.
Results We included 300,146 patients with a first MI, 34,027 (11.3%) with COPD. Peak troponin T & I was lower for those with COPD following both STEMI (troponin T: 0.51 ng/mL lower, adjusted% 17% lower (95% CI: 6–18%); troponin I: 5.49 ng/mL lower, adjusted% 12% lower (6–18%)) and non-STEMI (troponin T: 0.07 ng/mL lower, adjusted% 20% lower (95% CI: 16–25%); troponin I: 0.34 ng/mL lower, adjusted% 19% lower (15–23%)). The prognostic value of increased peak troponin was higher for COPD patients than those without COPD for troponin T, p-value for interaction = 0.02 (Table 1), but this was not apparent for troponin I p-value for interaction = 0.520.
Conclusion Cardiac Troponin T appears a better prognostic indicator for long-term outcome amongst COPD patients following an MI compared to Troponin I. Clinicians should not be reassured by relative lower troponin levels in COPD patients at the time of an MI.
Rothnie KJ, et al. Risk of myocardial infarction (MI) and death following MI in people with chronic obstructive pulmonary disease (COPD): a systematic review and meta-analysis. BMJ Open 2015;5(9):e007824.
Rothnie KJ, et al. Closing the mortality gap after a myocardial infarction in people with and without chronic obstructive pulmonary disease. Heart 2015;101(14):1103–10.