To Örebro University

Introduction: Smoking is a major risk factor for both chronic obstructive pulmonary disease (COPD) and myocardial infarction (MI). Systemic inflammation also contributes to both diseases and has been suggested as a potential target for intervention. Prevalence of COPD in those with a significant smoking history hospitalised for MI has not been well-characterised. We sought to obtain an accurate estimate of COPD burden in this group and characterise the population.

Methods: Two consecutive cohorts of patients hospitalised for MI with a smoking history of ≥10 pack-years were recruited in Sweden and the United Kingdom (UK). Baseline characteristics were recorded, including treatment with inhaled corticosteroids (ICS) and eosinophil count in blood. Microspirometry was performed using the Vitalograph COPD-6 device and symptom burden assessed using the COPD Assessment Test (CAT). The primary outcome was the prevalence of a preliminary diagnosis of clinically-significant COPD, here defined as a ratio of forced expiratory volume in 1 and 6 seconds (FEV1/FEV6) <0.7 and with FEV1 <80% of predicted value.

Results: In the UK cohort, 216 participants with MI (26% female, median age 60 (IQR 53–67) years, smoking history 32 (23–45) pack-years) were recruited. The proportion with any COPD was 36%. Clinically-significant COPD was found in 30 participants (13.9%, 95% CI 9.5–19.2). Of these, 43% had a prior COPD diagnosis, 20% had an eosinophil count ≥300 cells/mm3, mean CAT score was 14.4 ± 9.3), 80% had high symptom burden (CAT score >10) and 23% were receiving ICS. The Swedish cohort included 302 participants with MI (24% female, median age 68 (IQR 61–76) years, 26 (15–38) pack years), and clinically-significant COPD was found in 52 (17.2%; 12.9–21.5). In these 52 participants, 17% had a prior COPD diagnosis, 20% had an eosinophil count ≥300 cells/mm3, mean CAT score was 12.9 ± 7.2, 63% had CAT score ≥10 and 15% had treatment with ICS.

Conclusions: The prevalence of preliminary diagnosis of clinically-significant COPD in patients with a ≥10 pack-year smoking history hospitalised for MI is similar between two European cohorts and under-recognised. Further work is warranted to determine whether identification and treatment of COPD improves clinical outcomes following MI.