Zimmern cites shortcomings in published outcomes for anti-incontinence surgery

By Robin Russell / March 28-31, 2011

Studies that publish cure rates for anti-incontinence surgery in women often lack thorough patient follow-up data, leaving physicians with no yardstick to measure outcomes, a UT Southwestern researcher suggests in a literature review to be published in the Journal of Urology.

A significant number of studies either ignore or fail to explain follow-up data that is increasingly lost over time, said Dr. Philippe Zimmern, professor of urology and the review’s senior author. The trend toward minimally invasive procedures in the last two decades has increased surgical options to correct conditions such as stress urinary incontinence (SUI), but the study’s authors report that few studies in evidence-based publications provide detailed information on how patient data lost to follow-up (LTF) influences the reported cure rates.

“There is a large gray zone regarding the real outcome of these procedures,” Dr. Zimmern said. “Everyone wants to say they are the best and have great results — this is human nature. The fact is that the true results may not be as glorious as once stated.

Dr. Philippe Zimmern

“Patient satisfaction with quality of life for conditions such as SUI is just as important, if not more so, as the surgeons’ impressions of their own results.”

Stress urinary incontinence is a common condition typically affecting women. In females, SUI is caused by the gradual weakening of the vaginal wall support resulting in lack of support of the urethra and its sphincter valve during stressful efforts. It is caused by aging, childbirth, hormonal changes and genetic factors, and results in urine leakage during strenuous activity, such as coughing, sneezing, laughing or exercising.

In the review, researchers looked at PubMed publications from January 1995 to November 2009 and focused on the follow-up rate and reasons for LTF. Surgical treatment of SUI in women included “bladder suspension” procedures such as the open or laparoscopic abdominal anterior urethropexy (Burch or MMK) and the sling procedure that is performed vaginally. The review in Journal of Urology focused on 47 randomized clinical trials and 24 nonrandomized but prospective studies representing 11,000 female patients.

Published outcomes on the effectiveness of surgical procedures for SUI were reported as high as 70 to 80 percent. But after the review, Dr. Zimmern calculates that in a typical study of 200 patients with a reported success rate of 70 percent, an average LTF rate of 30 percent could potentially drop the actual success rate to anywhere from 49 percent to 79 percent.

Only 33 of the 71 examined articles provided details on sample size calculation. The mean sample was 155 patients and mean follow-up was two years. The LTF rate, however, grew from a mean of 8.1 percent at one year to 33 percent at three to five years.

Only one-fourth of the articles provided reasons for lack of follow-up, including family or work issues, patient death, refusal to return or other health problems. More than half of the articles (58 percent) provided no explanation for LTF. Only 10 percent defined LTF as treatment failures and recorded data accordingly; the remainder drew conclusions without considering LTF data, Dr. Zimmern said.

“Doctors typically hear back from patients who are doing well, so our conclusions are biased. We want to know about the others, too,” he said. “We need to recognize that we don’t know much about the long-term performance of these procedures, and so we should remain cautious when we discuss this topic with our patients.”

The review suggests LTF rates be included and calculated and recommends ways to enhance the validity of outcome findings, including designing follow-up instruments that incorporate brief visits, limited testing and short questionnaires, with possible patient incentives.

Dr. Rubiao Ou, a visiting urologist from Guangzhou, China, and Dr. Xian-Jin Xie, associate professor of clinical sciences at the Harold C. Simmons Comprehensive Cancer Center at UT Southwestern, also participated in the study.

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Dr. Zimmern holds the Jane and John Justin Distinguished Chair in Urology, in Honor of Claus G. Roehrborn, M.D.