Aim: To expand our understanding of the clinical importance to patients with stress urinary incontinence (SUI) of reductions in incontinence episode frequency (IEF) that fall short of a complete cure.
Methods: We used an integrated database that included data from 1,913 women with SUI who were enrolled in four randomized, placebo-controlled pharmaceutical clinical trials and examined the relationship between various levels of reduction in IEF and minimally clinical important difference (MCID) levels established for the validated Incontinence Quality of Life (I-QOL) questionnaire. The first decile of IEF reduction to exceed the within-group MCID was considered to be the point at which the reduction in IEF first became clinically important. The between-group MCID was then used to determine when further reductions in incontinence represented clinically relevant incremental improvements for patients.
Results: Improvements in condition-specific quality of life were not clinically important until the fifth decile of IEF reduction, representing a reduction in IEF >40% to <or=50%. Patients appreciated incremental clinically important benefits when IEF reductions exceeded 70%, with progressive improvements in condition-specific quality of life with higher levels of IEF reduction. The difference between a >70% to <or=80% reduction and a >90% to <or=100% reduction was clinically important.
Conclusion: Reductions in IEF <or=40% do not appear to be clinically important for women with SUI. Patients appear to recognize important clinical value at reductions of approximately 50% and important incremental clinical value at reductions of approximately 75% and 90-100%. These thresholds may not apply to women seeking non-pharmaceutical treatments for SUI.