Five-repetition sit-to-stand and mortality in COPD: a prospective cohort study

Background: The five repetition sit-to-stand test (5STS) is a validated simple functional test of exercise performance in chronic obstructive pulmonary disease (COPD) that requires little space or equipment and can be performed in most healthcare settings, including the home. We assessed the long-term predictive performance of the 5STS for mortality. Methods: We enrolled 838 patients with stable COPD from community-based clinics. We categorized patients according to quartiles of 5STS performance (from Quartile 1 = 19.07s or unable to perform 5STS). The primary outcome was all-cause mortality. We calculated hazard ratios (HR) using Cox proportional hazards regression, adjusting for age, sex, BMI, MRC Dyspnoea and FEV1 %predicted. Results: During follow-up (mean (SD) duration 1451 (653) days), we documented 170 (20.3%) deaths. Impaired 5STS performance, considered as categorical (Quartile 4 compared with Quartile 1) or continuous variable (per second increase), was independently associated with increased all-cause mortality risk on multivariable analysis (HR 1.71 (95% CI 1.05 to 2.78); p=0.03 and 1.01 (95% CI 1.00 to 1.02); p=0.002 respectively). Conclusion: We propose that the 5STS, a simple quick functional test, provides additional prognostic information in the community assessment of patients with COPD.