Urodynamic Testing before Stress Incontinence Surgery

Urodynamic Testing before Stress Incontinence Surgery

Abstract & Commentary

By Chiara Ghetti, MD

Associate Professor of Obstetrics and Gynecology, Division of Female Pelvic Medicine and Reconstructive Surgery, Washington University School of Medicine, St. Louis, MO

Dr. Ghetti reports no financial relationships relevant to this field of study.

Synopsis: For women with uncomplicated, demonstrable stress urinary incontinence, preoperative office evaluation alone was not inferior to evaluation with urodynamic testing for incontinence outcomes at 1 year.

Source: Nager C, et al. A randomized trial of urodynamic testing before stress-incontinence surgery. N Engl J Med 2012;366:1987-1997.

Up to 50% of u.s. women are affected by urinary incontinence, and of those¹ 15-80% have stress incontinence symptoms.^1,2 Stress incontinence is the complaint of involuntary leakage of urine on effort, physical exertion, sneezing, or coughing.³ Based on industry estimates reported by the FDA, approximately 260,000 mesh sling procedures were performed in 2010 for the treatment of stress incontinence.⁴ Urodynamics studies are often performed prior to surgery to assess incontinence symptoms and guide management decisions. Urodynamic testing involves evaluation of voiding uroflowmetry, post-void residual urine volume measurement, and pressure-flow studies with a catheter in place and storage function through cystometry and leak point pressure testing.³

The current study addresses the question of whether performing preoperative urodynamic testing improves incontinence treatment outcomes. This 11-center, randomized, noninferiority trial compared results of women who underwent office incontinence evaluation-only with results of women who underwent office evaluation and urodynamic testing prior to a planned surgery for uncomplicated stress urinary incontinence. Patients eligible for this trial were ≥ 21 years of age, had symptoms of stress urinary incontinence for a minimum of 3 months, had greater stress urinary incontinence scores vs urgency incontinence scores on the Medical, Epidemiological, and Social Aspects of Aging (MESA) questionnaire, had a postvoid residual urine volume < 150 mL, had negative urine analysis or culture, had visible urethral mobility, had a desire for surgery, and had observed transurethral loss of urine with cough or valsalva. Patients with prior incontinence surgery, pelvic irradiation, pelvic surgery within the prior 3 months, and anterior or apical pelvic organ prolapse of 1 cm or more distal to the hymen were excluded from the trial. Basic office evaluation consisted of: provocative stress test (performed at any volume and defined as visible transurethral loss of urine at time of cough or Valsalva), assessment of postvoiding residual, assessment of urethral mobility, and urine analysis or culture. The primary outcome was treatment success as measured by two validated instruments, the Urogenital Distress Inventory (UDI) and the Patient Global Impression of Improvement (PGII). Treatment success was defined as a reduction in UDI score from baseline to 12 months of ≥ 70% and a PGII response of "very much better" or "much better" at 12 months. A planned subgroup analysis was performed comparing surgical outcomes only among women in the study who ultimately underwent surgical treatment. For this subgroup analysis, successful treatment included a negative standard-volume stress test at 12 months in addition to the above definition.

A total of 630 women were randomized. Primary outcome data were available for 264 women in the urodynamic group and 259 in the office evaluation-only for the per-protocol analysis. Treatment success was 76.9% in the urodynamic group compared to 77.2% in the office evaluation-only group. The between-group difference was -0.3 percentage points (95% confidence interval, -7.5 to 6.9) and met the authors’ predetermined criterion for noninferiority of office evaluation alone. In the subgroup analysis of 443 women undergoing treatment, there was not a difference in the number of women who ultimately did not undergo surgery 17 (5.4%) in the urodynamic group vs 27 (8.6%) in the evaluation-only group (P = 0.12). Surgical treatment was successful in 154/222 (69.4%) in the urodynamic group vs 161/221 (72.9%) in the evaluation-only group (P = 0.42). The rate of successful treatment with office evaluation alone was not inferior to the rate among women who underwent urodynamic testing. The authors therefore conclude that in women with uncomplicated stress urinary incontinence, a basic office evaluation is sufficient for preoperative evaluation.

COMMENTARY

Urodynamic testing is invasive and uncomfortable for patients. It poses a risk of urinary tract infection and is very costly to the health care system. The role of urodynamic evaluation in the preoperative evaluation of stress incontinence remains controversial.⁵ In the UK, the National Institute for Health and Clinical Excellence published its 2006 guidelines on the management of urinary incontinence in women stating "the use of multichannel cystometry is not routinely recommended before surgery in women with a clearly defined clinical diagnosis of pure stress urinary incontinence."⁶ The Cochrane review published in 2009 prior to this trial concluded, "a larger definitive trial is needed, in which people are randomly allocated to management according to urodynamic findings or to standard management based on history and clinical examination."⁷ In a time of rising health care costs, this trial fills this critical gap in information.

This randomized noninferiority trial follows the modified CONSORT checklist for reporting noninferiority and equivalence randomized trials.⁸ For clarification, I will briefly review trial types as outlined in the CONSORT statement. Let’s assume two hypothetical interventions: A and B. A randomized controlled trial is designed to determine whether A is superior to B. An equivalence trial is designed to ascertain whether A is similar to B, while a non-inferiority trial is designed to determine whether A is no worse than B. In other words, "non-inferiority trials intend to show that one treatment has at least as much efficacy as another or is worse by a certain amount."⁸

This trial found that 1-year postoperative outcomes in women evaluated by basic office evaluation alone were not inferior to those of women who underwent formal urodynamic testing. To measure the possible benefits of urodynamic testing, this study used a general measure of postoperative lower urinary tract function that included urinary symptoms as well as patient perception of improvement. While this study does not address the role of urodynamic testing in more complicated patients, such as women with urge predominant incontinence, a history of prior incontinence surgery and pelvic organ prolapse, this study is very pertinent to a large number of our patients. Any woman with the complaint of urinary incontinence was assessed for eligibility. Eligibility criteria allowed for the inclusion of women with symptoms of both stress urinary incontinence and stress-predominant mixed urinary incontinence aiding the generalizability of the results to a large proportion of women with stress incontinence similar to what we see in everyday practice.

References

1. Melville JL, et al. Arch Intern Med 2005;165:537-542.
2. Hampel C, et al. Urology 1997;50(6A Suppl):4-14.
3. Haylen BT, et al. Neurourol Urodyn 2010;29:4-20.
4. Urogynecologic surgical mesh: Update on the safety and effectiveness of transvaginal placement for pelvic organ prolapse. Silver Spring, MD: U.S. Food and Drug Administration; July 2011.
5. Abrams P, et al. Neurourol Urodyn 2010;29:213-240.
6. Urinary incontinence: The management of urinary incontinence in women. NICE clinical guideline 40. London: National Institute for Health and Clinical Excellence, 2006:1-36.
7. Glazener CM, Lapitan MC. Cochrane Database Syst Rev 2002;3:CD003195-CD003195.
8. Piaggio G, et al. JAMA 2006;295:1152-1160.