Botulinum Toxin A Injection Versus Placebo as Treatment for Chronic Pelvic Pain: Evaluating the Influence of Patients’ Pretreatment Expectations

INTRODUCTION AND HYPOTHESIS: Chronic pelvic pain (CPP) impacts 6-27% of women aged 18-50 worldwide. To date, few studies have evaluated the influence of patients' pretreatment expectations on treatment outcomes in this population. We hypothesize that women's pretreatment expectations are associated with their perceived treatment outcomes. METHODS: This prospective cohort study included 94 women with CPP who received either botulinum toxin A or placebo injections, both combined with pelvic floor muscle therapy. Patients' expectations were assessed at baseline and at 26 weeks using questionnaires on pretreatment expectations, pelvic floor symptoms impact (PFIQ-7), health status (EQ-5D), and pain levels (VAS). Associations between expectations and outcomes were examined using multiple linear regression. RESULTS: Most women (78%) reported high expectations, but these were only met in one out of five women at 26 weeks follow-up. Low expectations of improvement were associated with a poorer impression of improvement at 26 weeks (p = 0.023). Women with high pretreatment expectations regarding their health status reported better EQ-5D health status scores at 26 weeks (p < 0.001). Treatment allocation did not affect expectations or outcomes. The baseline severity of symptoms of the individual questionnaires significantly influenced subsequent outcomes in the analysed questionnaires, reflecting parallel symptom trajectories. CONCLUSIONS: Patients' pretreatment expectations were associated with treatment outcomes in women with CPP. Low expectations were reflected by poorer perceived improvement at 26 weeks, providing new insights into the role of expectations in the management of CPP and trial outcomes.