Examining associations between baseline health-related quality of life and depression and physical functioning improvement following pulmonary rehabilitation

Purpose: This study examined whether health-related quality of life (HRQL) and depression assessed prior to pulmonary rehabilitation (PR) participation (ie, at baseline) predicted change in 6-min walk distance (6MWD) from baseline to end of PR. Methods: Patients with pulmonary disease were consecutively referred/enrolled in a PR program from 2009-2022 (N = 503). Baseline 6MWD was assessed along with self-report measures of HRQL (St George's Respiratory Questionnaire [SGRQ]) and depression (Geriatric Depression Scale [GDS]). The SGRQ total score was used to assess overall HRQL, and SGRQ subscales assessed pulmonary symptoms, activity limitations, and psychosocial impacts of pulmonary disease. Multiple linear regression was used to examine whether baseline SGRQ scores and depression predicted Δ6MWD. Results: Baseline SGRQ total score (F^(1,389)= 8.4, P=.004) and activity limitations (F^(1,388)= 4.8, P=.03) predicted Δ6MWD. Patients with an SGRQ activity limitation score ≤ 25th percentile showed the most 6MWD improvement (mean = 79.7 m, SE = 6.7), and significantly more improvement than participants scoring between the 50-75th percentiles (mean = 54.4 m, SE = 6.0) or >75th percentile (mean = 48.7 m, SE = 7.5). Patients scoring between the 25-50th percentiles (mean = 70.2 m, SE = 6.1) did not differ significantly from other groups. The SGRQ symptoms and impacts subscales were unrelated to Δ6MWD (F^(1,388)= 1.2-1.9, P>.05), as was depression (F^(1,311)= 0.0, P >.85). Conclusions: Patients with greater HRQL at baseline may experience greater physical functioning improvement following PR. Additional support for patients with lower HRQL (eg, adjunctive self-management interventions) may enhance PR outcomes, particularly for patients who report greater activity limitations. Alternatively, early referral to PR (ie, when less symptomatic) may also benefit physical function outcomes.