Comparison between the EQ-5D-3L and the SF-6D quality of life (QOL) questionnaires in patients with chronic obstructive pulmonary disease (COPD) undergoing lung volume reduction surgery (LVRS).

Abstract

Lung volume reduction surgery (LVRS) has been shown to improve lung function, but also improve the overall quality of life (QOL). The aim of this study is to compare two QOL questionnaires-EuroQol Questionnaire (EQ-5D-3L) and 36-item Short Form Health Survey (SF-36) in patients post-LVRS. All patients undergoing LVRS for severe chronic obstructive pulmonary disease (COPD) at a single center of excellence were analyzed (n = 94). Baseline demographic and clinical outcomes were characterized. Both EQ-5D-3L and SF-36 questionnaires were administered to all patients at baseline (n = 94) and at the end of 1year (n = 89) post-surgery. SF-36 was converted to Short Form six-dimensions (SF-6D) using standard algorithm. Correlation, discrimination, responsiveness and differences across the two questionnaires were examined. The mean age of patients enrolled in the cohort was 66years. There was significant increase in forced expiratory volume (FEV1, 43%), forced vital capacity (FVC 46%), diffusion capacity (DLCO 15%), 6min walk distance test (6MWD 21%) and a significant decrease in residual volume (RV 23%) at the end of 1-year follow-up. The overall mean utility index significantly improved for both SF-6D and EQ-5D-3L questionnaires at the end of follow-up (p = 0.0001). However, the magnitude of percentage increase was higher with EQ-5D-3L compared to SF-6D (32% vs. 13%). Stronger correlations confirmed convergent validity at the end of 1-year follow-up between similar domains. Both questionnaires failed to discriminate between different levels of disease severity post-LVRS in patients with severe COPD. Both questionnaires responded similarly in patients with COPD post-LVRS. Combining results from QOL questionnaire(s) along with symptoms of disease and history of exacerbation may be a possible solution for identifying disease severity in old and sick patients unwilling/unable to come to hospital for a pulmonary function test post-LVRS.