Minimal Clinically Important Difference (MCID) for the Pelvic Organ Prolapse-Urinary Incontinence Sexual Function Questionnaire – IUGA Revised (PISQ-IR)

Abstract

Background: To put statistically significant changes in patient reported outcome measurement (PROM) questionnaires into a clinical perspective, the concept of the minimal clinically important difference (MCID) can be used. Aim: To determine the MCID for the summary score for sexually active (SA) women of the Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire, IUGA-Revised (PISQ-IR), a validated instrument which assesses sexual functioning (SF) for patients suffering from a symptomatic pelvic floor disorder. Methods: Patients participating in a multicentre prospective cohort study comparing pessary therapy with surgery for a symptomatic pelvic organ prolapse (POP) filled in the PISQ-IR at baseline and 12 months’ follow-up. We used both an anchor-based as well as a distribution-based method to calculate the MCID for both treatment groups. The Patient Global Impression of Improvement (PGI-I) questionnaire and PISQ-IR question 19a about satisfaction with sexual functioning were used as anchors. For the distribution-based approach we used the effect size (ES). Outcomes: MCID for the SA summary score of the PISQ-IR. Results: Data of 243 women were used to calculate the MCID. In the pessary group, Kendall's tau-b correlation coefficients between the PISQ-IR summary score and both anchors were below the cut-off of 0.21, which implies the anchors cannot be used to calculate an MCID. In our surgery group, the PISQ-IR question 19a met the anchor criteria and 0.31 points increase in the PISQ-IR summary score was equal to an improvement of 1 point on question 19a about satisfaction with sexual functioning. Clinical implications: Future research on this subject should focus on clinical relevance of results rather than statistical significance only. Strengths & Limitations: Our main strength is the fact that we used both anchor-based and distribution-based methods to determine our MCID. Secondly, we set out to determine an MCID for both treatment groups separately, which relatively enhances the generalisability of our results. A limitation is that we were not able to estimate an MCID for the pessary group. Pruijssers B, van der Vaart L, Milani F, et al. Minimal Clinically Important Difference (MCID) for the Pelvic Organ Prolapse-Urinary Incontinence Sexual Function Questionnaire – IUGA Revised (PISQ-IR). J Sex Med 2021;18:1265–1270. Conclusion: We estimated the MCID for the PISQ-IR SA summary score to be 0.31 in our surgery group.