Abstract
Background
Debilitating symptoms of recurrent
Clostridioides difficile infection (rCDI) often lead to long-term effects on health-related quality-of-life (HRQOL). In ECOSPOR III, SER-109, an investigational oral microbiome therapeutic, was superior to placebo in reducing rCDI. We investigated the validity, reliability, and responsiveness of a 32-item, CDI-specific questionnaire (Cdiff32) across mental, physical, and social domains in patients with rCDI.
Methods
In this
post-hoc analysis of a Phase 3 clinical trial, 182 outpatients with rCDI completed Cdiff32 and EQ-5D at baseline, 1 and 8 weeks. Cdiff32 was evaluated for item performance, internal reliability, and convergent validity. To assess known-groups validity, Cdiff32 scores were compared across recurrent versus non-recurrent patients at week 1; internal responsiveness was evaluated in non-re current patients by 8 weeks by paired t-test.
Results
All 182 patients (mean age 65.5 ± 16.5, 59.9% female) completed baseline Cdiff32. Confirmatory factor analysis identified 3 domains (physical, mental, and social relationships) with good item fit. High internal reliability was demonstrated (Cronbach's alpha = 0.94 with all subscales > 0.80). Convergent validity was evidenced by significant correlations between Cdiff32 subscales and EQ-5D (r range: 0.29-0.37, p < 0.001). Cdiff32 differentiated recurrent from non-recurrent patients at week 1 (effect sizes: 0.38-0.42; p < 0.05 overall), with significant improvement from baseline to week 8 in non-recurrent patients (effect sizes: 0.75-1.02; p < 0.001 overall).
Conclusions
Cdiff32 is a valid, reliable, and responsive disease-specific HRQOL questionnaire fit-for-purpose for interventional treatment trials. The significant improvement in non-recurrent patients by 8 weeks demonstra tes the negative impact of rCDI on HRQOL.