Influence of comorbid heart disease on dyspnea and health status in patients with COPD - a cohort study.

Abstract

PurposeThe aim of this study was to examine the changing influence over time of comorbid heart disease on symptoms and health status in patients with COPD.Patients and methodsThis is a prospective cohort study of 495 COPD patients with a baseline in 2005 and follow-up in 2012. The study population was divided into three groups: patients without heart disease (no-HD), those diagnosed with heart disease during the study period (new-HD) and those with heart disease at baseline (HD). Symptoms were measured using the mMRC. Health status was measured using the Clinical COPD Questionnaire (CCQ) and the COPD Assessment Test (CAT; only available in 2012). Logistic regression with mMRC ≥2 and linear regression with CCQ and CAT scores in 2012 as dependent variables were performed unadjusted, adjusted for potential confounders, and additionally adjusted for baseline mMRC, respectively, CCQ scores.ResultsMean mMRC worsened from 2005 to 2012 as follows: for the no-HD group from 1.8 (±1.3) to 2.0 (±1.4), (P=0.003), for new-HD from 2.2 (±1.3) to 2.4 (±1.4), (P=0.16), and for HD from 2.2 (±1.3) to 2.5 (±1.4), (P=0.03). In logistic regression adjusted for potential confounding factors, HD (OR 1.71; 95% CI: 1.03–2.86) was associated with mMRC ≥2. Health status worsened from mean CCQ as follows: for no-HD from 1.9 (±1.2) to 2.1 (±1.3) with (P=0.01), for new-HD from 2.3 (±1.5) to 2.6 (±1.6) with (P=0.07), and for HD from 2.4 (±1.1) to 2.5 (±1.2) with (P=0.57). In linear regression adjusted for potential confounders, HD (regression coefficient 0.12; 95% CI: 0.04–5.91) and new-HD (0.15; 0.89–5.92) were associated with higher CAT scores. In CCQ functional state domain, new-HD (0.14; 0.18–1.16) and HD (0.12; 0.04–0.92) were associated with higher scores. After additional correction for baseline mMRC and CCQ, no statistically significant associations were found.ConclusionHeart disease contributes to lower health status and higher symptom burden in COPD but does not accelerate the worsening over time.