Comorbidities in chronic obstructive pulmonary disease: Results of a national multicenter research project

Background. Chronic obstructive pulmonary disease (COPD) is associated with various comorbidities, which influence the course of COPD and worsen prognosis. Objectives. The aim of this study was to analyze the comorbidities in a cohort of COPD patients in Poland during 12 months of observation. Material and methods. A total of 444 COPD patients (median age: 66.1 years) in all stages of airflow limitation severity were enrolled. Medical histories and a questionnaire concerning comorbidities were analyzed at baseline and after 12 months (data of 267 patients available). Anthropometric data, pulmonary function, and body mass index, airflow obstruction, dyspnea, and exercise capacity (BODE index) were assessed. Results. No comorbidities were reported in 9 patients (2.0%), 101 patients (22.7%) had 1-2 comorbidities, 243 (54.7%) had 3-5, and 91 (20.6%) had more than 5 comorbidities. Cardiovascular diseases (CVDs) were the most frequent ones, followed by peptic ulcer, obstructive sleep apnea (OSA), diabetes, gastroesophageal reflux disease (GERD), and osteoporosis; 11 patients had a history of lung cancer. Cachexia was observed in 11 cases, overweight in 136 cases and obesity in 139 cases. The incidence of CVDs increased with time. The number of comorbidities correlated with the body mass index (BMI) and the number of hospitalizations for extra-pulmonary causes, but not with airflow limitation. The BODE index score increased with the number of comorbidities. Conclusions. In a cohort of Polish COPD patients, the most frequent comorbidities were CVDs. The number of comorbidities affected the BODE index, but not airflow limitation. The BODE index is better than forced expiratory volume in 1 s (FEV1) in the rating of COPD patients' condition. The BMI correlated with the number of comorbidities as well as the number of hospitalizations for extra-pulmonary causes.