The effects of repeat fractional CO₂ laser for postmenopausal vaginal symptoms following unblinding from a double-blind RCT

OBJECTIVE: This study aimed to explore the effects of blinding on patient-reported outcomes. METHOD: Findings from this prospective open-label extension study were compared to a previous double-blind sham-controlled randomized trial. Women with any postmenopausal vaginal symptom previously receiving either active or sham vaginal fractional CO₂ laser were recruited from the index randomized controlled trial (RCT), and underwent an active laser protocol. Symptom severity was assessed by co-primary outcomes of a visual analog scale (VAS) for overall and most bothersome symptom and the Vulvovaginal Symptom Questionnaire (VSQ) to 12 months. RESULTS: Of the 25 participants, there was a significant improvement in the co-primary outcomes at 6 months from baseline (mean difference: overall vaginal symptoms VAS, 22.0 [95% confidence interval (CI) -32.2, -11.8]; most bothersome symptom VAS, -22.1 [95% CI -36.7, -7.5]; VSQ, -2.2 [95% CI -3.8, -0.6]). At 12 months, there was significant improvement in most bothersome symptom VAS (-17.8 [95% CI -35.3, -0.3]) and VSQ (-2.3 [95% CI -3.9, -0.8]) scores. There was no significant difference in the post-treatment improvement of the co-primary outcomes at 6 and 12 months following open-label laser treatment, when compared to index RCT outcomes following active laser and sham laser treatment, respectively. CONCLUSION: Blinding in randomized trials is essential for correctly interpreting clinical outcomes using lasers for genitourinary symptoms of menopause.