Validity of utility measures for women with pelvic organ prolapse

BACKGROUND: Pelvic organ prolapse is a common condition that frequently coexists with urinary and fecal incontinence. The impact of prolapse on quality of life is typically measured through condition-specific quality-of-life instruments. Utility preference scores are a standardized generic health-related quality-of-life measure that summarizes morbidity on a scale from 0 (death) to 1 (optimum health). Utility preference scores quantify disease severity and burden and are widely used in cost-effectiveness research. The validity of utility preference instruments in women with pelvic organ prolapse has not been established. OBJECTIVE: The objective of this study was to evaluate the construct validity of generic quality-of-life instruments for measuring utility scores in women with pelvic organ prolapse. Our hypothesis was that women with multiple pelvic floor disorders would have worse (lower) utility scores than women with pelvic organ prolapse only and that women with all 3 pelvic floor disorders would have the worst (lowest) utility scores. STUDY DESIGN: This was a prospective observational study of 286 women with pelvic floor disorders from a referral female pelvic medicine and reconstructive surgery practice. All women completed the following general health-related quality-of-life questionnaires: Health Utilities Index Mark 3, EuroQol, and Short Form 6D, as well as a visual analog scale. Pelvic floor symptom severity and condition-specific quality of life were measured using the Pelvic Floor Distress Inventory and Pelvic Floor Impact Questionnaire, respectively. We measured the relationship between utility scores and condition-specific quality-of-life scores and compared utility scores among 4 groups of women: (1) pelvic organ prolapse only, (2) pelvic organ prolapse and stress urinary incontinence, (3) pelvic organ prolapse and urgency urinary incontinence, and (4) pelvic organ prolapse, urinary incontinence, and fecal incontinence. RESULTS: Of 286 women enrolled, 191 (67%) had pelvic organ prolapse; mean age was 59 years and 73% were Caucasian. Among women with prolapse, 30 (16%) also had stress urinary incontinence, 39 (20%) had urgency urinary incontinence, and 42 (22%) had fecal incontinence. For the Health Utilities Index Mark 3, EuroQol, and Short Form 6D, the pattern in utility scores was noted to be lowest (worst) in the prolapse thorn urinary incontinence thorn fecal incontinence group (0.73-0.76), followed by the prolapse thorn urgency urinary incontinence group (0.77-0.85) and utility scores were the highest (best) for the prolapse only group (0.80-0.86). Utility scores from all generic instruments except the visual analog scale were significantly correlated with the Pelvic Floor Distress Inventory and Pelvic Floor Impact Questionnaire total scores (r values -0.26 to -0.57), and prolapse, bladder, and bowel subscales (r values -0.16 to -0.50). Utility scores from all instruments except the visual analog scale were highly correlated with each other (r = 0.53-0.69, P<.0001). CONCLUSION: The Health Utilities Index Mark 3, EuroQol, and Short Form 6D, but not the visual analog scale, provide valid measurements for utility scores in women with pelvic organ prolapse and associated pelvic floor disorders and could potentially be used for cost-effectiveness research.