Effect of comorbidities on response to pulmonary rehabilitation in patients with chronic obstructive pulmonary disease

Background and objective: Patients with chronic obstructive pulmonary disease (COPD) typically manifest with worsening dyspnea, poor exercise tolerance and diminished quality of life. In addition, comorbidities are commonly reported in these patients, complicating management strategies. Pulmonary rehabilitation (PR) is an evidence-based multimodality therapy increasingly prescribed for symptomatic COPD patients. This study aimed to assess the impact of comorbidities on achieving proper response to PR in patients with COPD. Methods: Forty patients with COPD were enrolled in PR program of upper and lower extremity exercise, and were prospectively followed. The minimal clinically important difference (MCID) was used as a cut-off to determine response in six-minute walk distance (6MWD), modified Medical Research Council (mMRC) dyspnea scale, Saint George Respiratory Questionnaire (SGRQ) and estimated maximum oxygen consumption (VO2max). According to comorbidities patients were divided into three groups: patients without comorbidities, patients with one comorbidity and patients with more than one comorbidity. Results: Comorbidities were diagnosed in 34 patients (85%). Patients with one or more comorbidity had significantly worse baseline mMRC, 6MWD, SGRQ score and VO2max but not FEV1%. Thirty-two patients (80%) showed improvements beyond the MCID. Factors that predicted better response included higher arterial PaCO2, presence of osteoporosis, and lower baseline 6MWD, mMRC and VO2max. Conclusions: Pulmonary rehabilitation can be offered to COPD patients from different severity stages. Comorbidities occur very commonly in patients with COPD and their presence worsens the baseline functional status in these patients which makes them more liable to achieve larger benefits from PR