Sustained effects of integrated COPD management on health status and exercise capacity in primary care patients

BACKGROUND Chronic obstructive pulmonary disease (COPD) constitutes a growing health care problem worldwide. Integrated disease management (IDM) of mild to moderate COPD patients has been demonstrated to improve exercise capacity and health status after one year, but long-term results are currently lacking in primary care. METHODS Long-term data from the Bocholtz study, a controlled clinical trial comparing the effects of IDM versus usual care on health status in 106 primary care COPD patients during 24 months of follow-up, were analyzed using the Clinical COPD Questionnaire (CCQ). In addition, the Kroonluchter IDM implementation program has treated 216 primary care patients with mild to moderate COPD since 2006. Longitudinal six-minute walking distance (6MWD) results for patients reaching 24 months of follow-up were analyzed using paired-sample t-tests. In prespecified subgroup analyses, the differential effects of baseline CCQ score, Medical Research Council (MRC) dyspnea score, and 6MWD were investigated. RESULTS In the Bocholtz study, subjects were of mean age 64 years, with an average postbronchodilator forced expiratory volume in one second (FEV(1)) of 63% predicted and an FEV(1)/forced vital capacity (FVC) ratio of 0.56. No significant differences existed between groups at baseline. CCQ improved significantly and in a clinically relevant manner by 0.4 points over 24 months; effect sizes were doubled in patients with CCQ > 1 at baseline and tripled in patients with MRC dyspnea score >2. In the Kroonluchter cohort, 56 subjects completed follow-up, were of mean age 69 years, with an FEV(1)/FVC ratio of 0.59, while their postbronchodilator FEV(1) of 65% predicted was somewhat lower than in the total group. 6MWD improved significantly and in a clinically relevant manner up to 93 m at 12 months and was sustained at 83 m over 24 months; this effect occurred faster in patients with MRC dyspnea score >2. In patients with baseline 6MWD < 400 m the improvement remained >100 m at 24 months. CONCLUSION In this study, IDM improved and sustained health status and exercise capacity in primary care COPD patients during two years of follow-up. Improvements in health status are consistently higher in patients with CCQ > 1 at baseline, being strongest in patients with baseline MRC dyspnea score >2. Improvements in exercise capacity remain highest in patients with 6MWD < 400 m at baseline and seem to occur earlier in patients with MRC dyspnea score >2.