Cough-induced leak point pressure : Reproducibility and validity of a new urodynamic method to assess stress incontinence in women

Sammanfattning: Urinary incontinence is defined as "involuntary loss of urine which is objectively demonstrable and a social or hygienic problem." The symptom of urinary incontinence is common and more prevalent in women than in men. There is a lack of standardized, reproducible and validated methods with which to diagnose urinary incontinence and to assess the effect of treatment. The objective of this thesis was to develop and validate a simple, yet reproducible and accurate, urodynamic test applicable in the evaluation of stress incontinence, the most common type of incontinence in women. The test, cough-induced leak point pressure (CILPP), detects leakage electronically and measures, by the vaginal route, the cough-induced exertion necessary to elicit leakage. Long-term reproducibility was shown to be satisfactory with a repeat test having a 95% chance of being within ±28% of the first test. The reproducibility thus appears to be better than that of pad tests and standard urodynamic parameters.The criterion validity was established in that the sensitivity of CILPP in diagnosing stress incontinence was consistently higher than that of the standard measures such as Valsalva leak point pressure and the cough pressure profile. The construct validity of CILPP was confirmed in that it showed significant increase in response to treatment of known efficacy, i.e. a vaginal continence device and the pharmacological agent phenylpropanolamine. CILPP was also shown to possess the ability to distinguish between patients and controls. The content validity of CILPP was verified by the correspondence to history and established urodynamic measures such as the urethral pressure profile and pad test.---Cough-induced leak-point pressure is a dynamic, quantitative, and comprehensive measure of urethral closure function with established reproducibility and validity. It is proposed that leak point pressure measurement should constitute a 'gold standard' to diagnose stress incontinence and to determine the effect of treatment.