The Prevalence of COPD in Individuals with Acute Coronary Syndrome: A Spirometry-Based Screening Study

The prevalence of COPD among individuals with acute coronary syndrome (ACS) is estimated at 5% to 18%, and COPD appears to be a predictor of poor outcome. Diagnosis of COPD has mostly been based on medical records without spirometry. As COPD is largely undiagnosed and misdiagnosed, the prevalence and clinical significance of COPD in the ACS population has not been reliably assessed. The present study aimed to estimate the prevalence of COPD in patients with ACS and evaluate the accuracy of medical record-based COPD diagnoses.

This was a single-centre spirometry screening study for COPD in patients admitted for ACS in the county of Jämtland, Sweden. Patient medical records were reviewed to register previous medical history. Spirometry was performed prior to discharge or at the first follow-up outpatient visit after discharge. COPD was defined as a post-bronchodilator FEV1/FVC of <0.7 or below lower limit of normal.

Of 743 eligible patients, 407 performed spirometry. Five percent had COPD according to medical records; 11% and 5% fulfilled spirometric criteria of COPD according to FEV1/FVC of < 0.7 (p = 0.002) and below lower limit of normal definitions, respectively. "COPD according to medical history" had a sensitivity of 23%, specificity of 98%, positive predictive value of 53%, and negative predictive value of 91% compared with spirometric COPD FEV1/FVC of < 0.7 CONCLUSIONS: In patients with ACS, COPD is underdiagnosed and misdiagnosed. We raise concerns regarding the validity of medical record-based COPD in evaluating the biological and clinical association between COPD and coronary disease.

ISRCTN number 05697808 (www. controlled-trials.com).