In the largest and most rigorous U.S. trial comparing two traditional operations for stress urinary incontinence (SUI) in women, a team of urologists and urogynecologists supported by the National Institutes of Health (NIH) has found that a sling procedure helps more women achieve dryness than the Burch technique.
"For the first time, we have a meticulous, relatively long-term comparison of these common surgeries in women," said Leroy M. Nyberg Jr., Ph.D., M.D., director of urology research at the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). "Women who participated in this study have made it possible for many women with stress incontinence and their doctors to make more-informed choices based on clear benefits, risks and personal preferences."
The Stress Incontinence Surgical Treatment Efficacy Trial (SISTEr) found that significantly more women with a sling made from the patient's own tissue and placed around the urethra for additional support were dry, compared to women with a Burch colposuspension, in which sutures are attached to a pelvic ligament to support the urethra. Both approaches are illustrated below. Two years after surgery, 47 percent of women who had the sling procedure and 38 percent who had a Burch were dry overall, including leakage that could have been caused by urge incontinence. Considering only stress-specific leakage, 66 percent of women with a sling and 49 percent with a Burch procedure were dry.
SISTEr randomized 655 women with either pure SUI or a combination of stress and urge incontinence to receive a fascial sling or a Burch. Complete information on measures used to assess urinary incontinence was available for 520 participants (79 percent) 24 months after surgery. Quality of life, patient satisfaction and side effects were also studied.
While most women in the study were satisfied with the results of treatment, those with a sling were significantly more satisfied. Eighty-six percent with a sling were satisfied, compared to 78 percent of the Burch group.
Side effects were more common among women with slings, tempering the positive results of the procedure. The most common side effect was urinary tract infections, which occurred in 63 percent of women with a sling and 47 percent of the Burch group. Women with a sling also had more voiding problems (14 percent versus 2 percent) and persistent urge incontinence, the loss of urine just before feeling a strong, sudden urge to empty the bladder (27 percent versus 20 percent). Nineteen women with slings who had difficulty voiding after treatment needed surgery to correct the problem; none in the Burch group needed corrective surgery for voiding problems.
Stress urinary incontinence, in which coughing, laughing, sneezing, running or lifting heavy objects causes urine to leak, is commonly treated with surgery designed to provide additional support to the bladder neck and urethra during increases in abdominal pressure that occur with these kinds of activities. However, randomized, controlled trials comparing these operations are rare. Studies predating SISTEr were small, short-term, or less stringent about diagnostic criteria and outcome measures, producing inconsistent results across studies. SISTEr set a higher bar by standardizing definitions, clinical evaluations, and surgical procedures at all sites and by using "composite outcome measures and a more rigid definition of success compared to other studies," according to the study.
SISTEr defined two levels of treatment success. Stress-specific success required that women have no symptoms of leakage during physical activities, no leakage during a valsalva and cough stress-test, and no re-treatment for the problem. Overall success required that women meet SUI-specific treatment goals, have a negative pad test and have no leakage episodes recorded on a three-day voiding diary.
This higher bar may account for lower success rates in SISTEr than in earlier trials, but it also "establishes a template for conducting surgical trials for urinary incontinence and for other urological conditions," said John W. Kusek, Ph.D., co-director of kidney and urology trials at NIDDK.
NIH's National Institute of Diabetes and Digestive and Kidney Diseases, National Institute of Child Health and Human Development and Office of Research on Women's Health funded the Urinary Incontinence Treatment Network, a group of nine clinical centers and a biostatistical center, to conduct a series of rigorous, long-term trials of common incontinence therapies.
Urinary incontinence is a common and costly condition that reduces quality of life for American women. NIDDK's Urologic Diseases in America project reports that up to three-fourths of women have some degree of incontinence, and the direct cost of incontinence for women was $12.4 billion in 1995.
SISTEr is the first trial completed by UITN, with two other studies in the wings. Results of the second trial, the Behavior Enhances Drug Reduction of Incontinence (BE-DRI), for urge incontinence, are expected later this year. BE-DRI asked 307 women to make changes such as emptying the bladder on a regular schedule and to practice Kegel exercises to strengthen pelvic muscles to learn if these common treatments would allow women to stop drug therapy and maintain the same degree of bladder control.