Aim: To establish, for the first time, the clinically important differences for the ICIQ-UI-SF and ICIQ-FLUTS questionnaires following surgical and conservative treatments for stress-predominant urinary incontinence in women.
Methods: Data from the SIMS and OPAL randomised controlled trials were analysed using an anchor-based method. Clinically important difference (CID; score change indicating a successful outcome) and minimal important difference (MID; score change indicating the smallest noticeable difference) were estimated using the PGI-I scale as the anchor.
Results: For ICIQ-UI-SF, following surgical management, CIDs were 5.0 (95%CI 4.3, 5.6) at 1 year and 4.9 points (95%CI 4.2, 5.5) at 3 years, while following conservative management, CIDs were 4.0 (95%CI 3.4, 4.5) at 1 year and 4.6 points (95%CI 4.0, 5.2) at 2 years. For ICIQ-FLUTS, the CID was 3.4 points (95%CI 2.9, 4.0) at 1 year for both surgical and conservative management. MIDs for ICIQ-UI-SF, after surgical treatment, were 4.7 (95% CI 3.2, 6.1) at 1 year and 1.6 points (95%CI -0.2, 3.0) at 3 years, and after conservative treatment they were 1.7 (95% CI 1.0, 2.5) at 1 year and 1.9 points (95%CI 1.1, 2.7) at 2 years. For ICIQ-FLUTS, MIDs were 1.8 (95% CI 0.6, 3.1) at 1 year and 3.2 points (95%CI 2.0, 4.4) at 2 years after surgical treatment, and 1.3 (95%CI 0.6, 1.9) at 1 year and 1.9 points (95%CI 1.1, 2.6) at 2 years after conservative treatment.
Conclusion: Our study is the first to establish the CID for the ICIQ-UI-SF and ICIQ-FLUTS that women would associate with a successful outcome 3-years post-surgery and 2-years post-conservative treatment of stress-predominant urinary incontinence. The MID was lower following conservative compared to surgical treatment.
Keywords: Clinically important difference; ICIQ-FLUTS; ICIQ-SF; Minimal important difference; PGI-I; Stress urinary incontinence.
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