Effect of Pulmonary Rehabilitation on Quality of Life in Patients With COPD: The Use of SF-36 Summary Scores as Outcomes Measures

PURPOSE: Pulmonary rehabilitation (PR) is an accepted therapy for patients with chronic obstructive pulmonary disease (COPD), improving both exercise capacity and quality of life (QOL). Generic measures of QOL have been criticized as being insensitive to detecting the improvement in QOL after PR in contrast to disease-specific instruments. The authors looked at the Medical Outcomes Survey Short Form 36-item questionnaire (SF-36), a generic QOL measure, to detect changes in QOL in COPD patients after completion of PR. METHODS: Patients with COPD who participated in a PR program completed the QOL questionnaire before and after completion of PR. Exercise tolerance was assessed by the 6-minute walking test. Quality of life was assessed by the SF-36; the authors calculated its eight dimensions as well as mental (MCS) and physical (PCS) component summary scores. RESULTS: The patients realized a significant improvement in exercise tolerance; 6-minute walking test distance increased from 470 +/- 104 m (mean +/- standard deviation) to 536 +/- 133 m (P = 0.0006) after PR. Quality of life also improved in nearly all dimensions and in both summary scores; PCS improved from 26.1 +/- 8.0 before PR to 30.5 +/- 9.0 after PR (P = 0.008) and MCS improved from 27.9 +/- 7.0 before PR to 34.1 +/- 5.0 after PR (P = 0.0002). CONCLUSION: The SF-36 and its summary scores are sensitive instruments to detect improvement in QOL in COPD patients after PR.