The minimum important difference for the Pelvic Organ Prolapse-Urinary Incontinence Sexual Function Questionnaire

Although the Pelvic Organ Prolapse-Urinary Incontinence Sexual Function Questionnaire (PISQ) is widely used to assess sexual function in women, the minimum important difference (MID) (defined as the smallest difference in scores of a patient-reported outcome measure that is perceived by patients as beneficial or harmful and which would lead the clinician to consider a change in treatment) is not known. The objective was to estimate the MID for the PISQ.

Two study populations, one of women with overactive bladder (OAB) and urgency UI (UUI) treated with tolterodine in a placebo-controlled trial (cohort I), and one of women treated surgically for prolapse and/or UI (cohort II) were used. Cohort I anchors were the Overactive Bladder Questionnaire (OAB-q), the Patient Perception of Bladder Condition (PPBC), the Patient Perception of Treatment Benefit Questionnaire (PPTBQ), and the change in number of UUI episodes in bladder diaries. Distribution MIDs were also calculated.

In the anchor-based analysis, the MID values for changes in PISQ total scores at 3 months in cohort I were 5 points using the UUI anchor (diary-dry women), 5 points using the PPBC anchor, 5 points with the PPTBQ, and 9 points with the OAB-q. In cohort II, the MID at week 12 in PISQ total scores was 7 points in women with improved IIQ-7 scores. The distribution-based MID in PISQ total scores was 5.3 points in cohort I and 5.8 points in cohort II.

A reasonable estimate of MID for the PISQ total score is 6 points. Improvements that meet these thresholds may be considered clinically important.