Regardless of surgical technique, women who have had a hysterectomy are at a much greater risk for needing stress-urinary-incontinence surgery, according to the results of a nationwide, population-based, cohort study reported in the October 27 issue of The Lancet. An accompanying Comment notes that results from this registry data study differ significantly from those of previous studies, which were smaller and gathered the data differently.

“Hysterectomy for benign indications has been associated with an increased risk for lower-urinary-tract sequela, but results have been inconclusive,” write Daniel Altman, MD, from Danderyd University Hospital in Stockholm, Sweden, and colleagues. “We aimed to establish the risk for stress-urinary-incontinence surgery after hysterectomy for benign indications.”

Using the Swedish Inpatient Registry from 1973 to 2003, the investigators compared the occurrence of stress-urinary-incontinence surgery in 165,260 women who had undergone hysterectomy (exposed cohort) with that in a control group of 479,506 individuals, matched by year of birth and county of residence, who had not had a hysterectomy (unexposed cohort). Cox’s proportional hazards regression was used to determine hazard ratios (HRs).

From 1973 to 2003, the rate of stress-urinary-incontinence surgery per 100,000 person-years was 179 (95% confidence interval [CI], 173 – 186) in the exposed cohort, compared with 76 (95% CI, 73 – 79) in the unexposed cohort. Regardless of surgical technique, risk for stress-urinary-incontinence surgery in the group that underwent hysterectomy was more than double that in the unexposed cohort (HR, 2.4; 95% CI, 2.3 – 2.5).

This risk was slightly different depending on duration of follow-up. The highest overall risk was within 5 years of surgery (HR, 2.7; 95% CI, 2.5 – 2.9), and the lowest risk was observed after an observation period of 10 years or more (HR, 2.1; 95% CI, 1.9 – 2.2).

“Hysterectomy for benign indications, irrespective of surgical technique, increases the risk for subsequent stress-urinary-incontinence surgery,” the authors write. “Women should be counselled on associated risks related to hysterectomy, and other treatment options should be considered before surgery…. Our findings have important public-health and clinical applications, in view of the many women undergoing hysterectomy for benign indications.”

Reasons proposed by the study authors to explain the increased risk of needing stress-urinary-incontinence surgery include surgical trauma caused when the uterus and cervix are severed from pelvic floor supportive tissues. In addition, hysterectomy could compromise the urethral sphincter mechanism, as well as urethral and bladder neck support.

Study limitations include the inability to account for some potential behavioral and lifestyle factors possibly associated with stress urinary incontinence, such as smoking, strenuous work, and body mass index.

The Swedish Society of Medicine and Eli Lilly, Sweden, supported this study. The authors have disclosed no relevant financial relationships.

In the accompanying Comment, Adam Magos, MD, from Royal Free Hospital, London, United Kingdom, notes that these findings conflict with those of earlier studies, including those from Dr. Altman’s group.

“The truth is that there have been many studies that looked at the after-effects of hysterectomy in terms of urinary symptoms and bladder function, but there is no consensus,” Dr. Magos writes. “Admittedly, previous studies have tended to be smaller with short follow-ups, but more than one have reported either no detrimental effect of hysterectomy or even benefits.

“It seems likely that a simple hysterectomy does not adversely affect bladder function, at least initially, and indeed pre-existing symptoms may improve,” Dr. Magos writes. “If hysterectomy-induced urinary stress incontinence is a reality, it only becomes so several years after the surgery, as already suggested. Or perhaps it has nothing to do with hysterectomy, and women who agree to hysterectomy are just different in ways that we do not yet understand.”

Lancet. 2007;370:1494–1499.

Laurie Barclay, MD is a freelance reviewer and writer for Medscape.