Sling shows higher overall success than Burch in treating stress urinary incontinence

July 1, 2007

Two-year results of the prospective, randomized Stress Incontinence Surgical Treatment Efficacy Trial (SISTEr) show significantly higher success rates in women who undergo the rectus fascial pubovaginal sling procedure compared to those in women who receive a Burch colposuspension.

Anaheim, CA—Two-year results of the prospective, randomized Stress Incontinence Surgical Treatment Efficacy Trial (SISTEr) show significantly higher success rates in women who undergo the rectus fascial pubovaginal sling procedure compared to those in women who receive a Burch colposuspension. Satisfaction rates were high for both procedures, although the sling procedure was associated with a significantly higher level of satisfaction, while morbidity was lower among women who underwent the Burch colposuspension, study investigators reported at the AUA annual meeting.

"This is one of the largest clinical trials assessing surgical therapies for stress urinary incontinence [SUI] ever conducted in the United States, and it uses rigorous definitions and standardized measures for evaluation of outcomes. Its results will allow physicians and patients to have a more educated conversation about procedures for SUI and what can be expected in terms of efficacy and complications," said co-author Michael E. Albo, MD, associate professor of surgery/urology at the University of California, San Diego.

SISTEr was conducted at the nine clinical centers that comprise the Urinary Incontinence Treatment Network, a clinical trials network created by the National Institute of Diabetes and Digestive and Kidney Diseases for the purpose of obtaining higher levels of evidence about incontinence treatments. The New England Research Institutes serves as the biostatistics center for the network.

"The two procedures compared in SISTEr have been considered the gold standards for the surgical treatment of SUI, but they have never been directly compared in an adequately designed and powered clinical trial," Dr. Albo told Urology Times.

Women were eligible to enroll in SISTEr if they had stress-predominant urinary incontinence symptoms, a positive cough/Valsalva stress test, urethral hypermobility on Q-tip exam, and if they desired surgical treatment for their incontinence. A total of 655 women were randomized in the operating room to undergo either the sling or Burch procedure; the two groups were comparable in preoperative demographic, clinical, and urodynamic features. Follow-up at regular intervals was conducted through 24 months, and 79% of the women had complete data at that visit.

Treatment success was defined using a rigorous definition that was a composite measure incorporating subjective and objective findings. Overall success re-quired that women meet all of the following criteria: no self-reported SUI symptoms on questionnaire, a negative 24-hour pad test (p=.01).

Considering the outcome of SUI-specific success, defined by absence of self-reported SUI symptoms, a negative stress test, and no re-treatment for SUI, the success rates for the sling and Burch procedures were 66% and 49%, respectively (pp=.02).

"The finding that satisfaction rates were higher than the success rates in both groups suggests there may be benefits from surgery that are not necessarily identified within our strict definition of cure," noted Peggy Norton, MD, who is also a SISTEr trial investigator and is professor of obstetrics and gynecology, University of Utah School of Medicine, Salt Lake City.

Safety evaluations showed that, compared with the women who underwent the Burch procedure, women in the sling group had more urinary tract infections (299 vs. 202 events), along with higher rates of voiding dysfunction (14% vs. 2%, pp=.04).

Further study planned
Eighty percent of the women who reached the 24-month visit in the SISTEr trial have enrolled in an expansion phase that plans follow-up for another 5 years.

"We know from the literature that failure rates increase as the interval from surgery lengthens. The expansion trial will provide more information on the longer-term efficacy and safety of these two procedures," Dr. Albo said.

The urologists and urogynecologists who comprise the Urinary Incontinence Treatment Network also have completed a study in women with urge incontinence that investigated the effect of adding behavioral therapy to pharmacologic treatment. The network is enrolling patients in a third study comparing two of the most common minimally invasive sling procedures for SUI.

"The SISTEr trial demonstrates that rigorous clinical trials designed to provide the highest levels of evidence can be conducted successfully. In cooperation with our patients and continued support from the NIDDK, we can use this as a model for evaluating other types of therapies that are currently available," Dr. Norton said.

Results of SISTEr were also published in the New England Journal of Medicine (2007; 356:2143-55).