Increased risk of stress urinary incontinence surgery after hysterectomy for benign indication - a population-based cohort study

BACKGROUND: Hysterectomy is a common procedure used to treat different gynecologic conditions. The association between hysterectomy for benign indication and stress urinary incontinence has previously been established. Stress urinary incontinence can be treated surgically, and options have improved after introduction of the midurethral sling procedure in 1998.

OBJECTIVE: This study aimed to estimate the risk of stress urinary incontinence surgery after hysterectomy for benign indication.

STUDY DESIGN: The study was carried out as a matched register-based cohort study including Danish women born from 1947 to 2000. Women who underwent hysterectomy for benign indication were matched to nonhysterectomized women in a 1:5 ratio on the basis of age and calendar year of hysterectomy. The risk of stress urinary incontinence surgery after hysterectomy was estimated. We adjusted for income, educational level, and parity. The risk of stress urinary incontinence surgery was further estimated in a subcohort excluding all vaginal hysterectomies. The joint effect of hysterectomy and parity was estimated in the main cohort, and the joint effect of hysterectomy and vaginal birth or cesarean delivery on stress urinary incontinence surgery was explored in a subgroup of women who only had 1 mode of delivery. All analyses were made using the Cox proportional hazards model.

RESULTS: We included 83,370 women who underwent hysterectomy and 413,969 reference women. The overall risk of stress urinary incontinence surgery was more than doubled for women who underwent hysterectomy (adjusted hazard ratio, 2.6; 95% confidence interval, 2.4-2.8). The adjusted hazard ratio decreased slightly to 2.4 (95% confidence interval, 2.3-2.6) when excluding all vaginal hysterectomies. We found a trend of increasing risk of stress urinary incontinence surgery with increased parity among both women who underwent hysterectomy and the reference group. In the subgroup of women who only had 1 mode of delivery, we found the risk of stress urinary incontinence surgery to be particularly increased for women with a history of ≥1 vaginal births. The hazard ratio was 15.1 (95% confidence interval, 10.3-22.1) for women with a history of 1 vaginal birth who underwent hysterectomy, whereas the hazard ratio for women in the reference group with 1 vaginal birth was 5.1 (95% confidence interval, 3.8-8.1). Overall, women who underwent hysterectomy had a 3 times higher risk of stress urinary incontinence surgery than the reference group, irrespective of the number of vaginal births.

CONCLUSION: This study indicates, in accordance with previous studies, that hysterectomy increases the risk of subsequent stress urinary incontinence surgery. Women should be informed and gynecologists include this knowledge in decision-making. Further precautions should be taken when treating parous women, particularly those with a history of ≥1 vaginal births.