Assessment of health‐related quality of life as an outcome measure in granulomatosis with polyangiitis (Wegener's)

Abstract

To assess a generic measure of health-related quality of life (HRQOL) as an outcome measure in granulomatosis with polyangiitis (Wegener's) (GPA). Subjects were participants in the Wegener's Granulomatosis Etanercept Trial (WGET) or the Vasculitis Clinical Research Consortium Longitudinal Study (VCRC-LS). HRQOL was assessed with the Short Form 36 (SF-36) health survey that includes physical and mental component summary scores (PCS and MCS, respectively). Disease activity was assessed with the Birmingham Vasculitis Activity Score for Wegener's Granulomatosis (BVAS/WG). The data from 180 subjects in the WGET (median followup 2.3 years, mean number of visits 10) and 237 subjects in the VCRC-LS (median followup 2.0 years, mean number of visits 8) were analyzed. A 1 unit increase in the BVAS/WG corresponded to a 1.15 unit (95% confidence interval [95% CI] 1.02, 1.29) decrease for the PCS and a 0.93 (95% CI 0.78, 1.07) decrease for the MCS in the WGET, and to a 1.16 unit decrease for the PCS (95% CI 0.94, 1.39) and a 0.79 unit decrease for the MCS (95% CI 0.51, 1.39) in the VCRC-LS. In both arms of the WGET study, SF-36 measures improved rapidly during the first 6 weeks of treatment followed by gradual improvement among patients achieving sustained remission (0.5 improvement in PCS per 3 months), but worsened slightly (0.03 decrease in PCS every 3 months) among patients not achieving sustained remission (P = 0.005). HRQOL, as measured by the SF-36, is reduced among patients with GPA. SF-36 measures are modestly associated with other disease outcomes and discriminate between disease states of importance in GPA.