Performance of the American Urological Association Symptom Index with and without an additional urge incontinence item

Abstract

Objective<br>To examine the value of adding an urge incontinence question to the American Urological Association Symptom Index (AUASI) among men in the Complementary and Alternative Medicine for Urological Symptoms (CAMUS) trial.<br><br>Methods<br>The CAMUS study was a randomized trial of Saw palmetto fruit extract versus placebo among men aged ?45 years with an AUASI score of ?8 and ?24. The baseline measurements included the AUASI, a question about urge incontinence (UI), the International Prostate Symptom Score quality of life question, and the Benign Prostatic Hyperplasia Impact Index. We correlated the items and scales and examined whether adding the UI question resulted in better prediction of disease-specific health status.<br><br>Results<br>The mean age of the 369 men in the CAMUS trial was 61 years, and mean baseline AUASI score was 14.6. UI was reported infrequently; about 82% of the respondents answered the question “not at all” or “<1 time in 5.” UI correlated significantly with all other AUASI items, except for weak stream; the strongest correlation was to urgency (R = 0.51, P < .0001). The correlation between the AUASI score and the AUASI + UI score was 0.98 (P < .0001). In a logistic regression analysis predicting the International Prostate Symptom Score quality of life score, adding UI to the AUASI slightly increased the discriminating ability (c statistic increased from 0.77 to 0.78, P < .0001). Similarly, in a linear regression analysis predicting the Benign Prostatic Hyperplasia Impact Index score, adding UI to the AUASI slightly increased the predictive ability (R2 statistic increased from 0.22 to 0.26, P < .0001).<br><br>Conclusion<br>According to our analysis in the CAMUS trial population, the value of adding a UI question to the AUASI in terms of predicting bother seemed small at best.<br>The American Urological Association Symptom Index (AUASI) for quantifying lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH) was first published in 1992.1 Subsequently, the 7-item scale and a 1-item bother question, scored separately, became known as the International Prostate Symptom Score (IPSS). [2] and [3]<br>Since its introduction almost 20 years ago, the AUASI/IPSS has been widely used in both clinical practice and clinical research. The use of the index in clinical practice has been recommended by both American and international clinical practice guidelines. [4] and [5] The index has been translated and linguistically validated in 56 different languages and is commonly used for LUTS/BPH research. An ISI Web of Knowledge (Thomson Reuters, New York, NY) search performed on March 24, 2010 identified 1192 citations to the original 1992 AUASI validation report in the subsequent published scientific literature from investigators in 49 countries.<br>Despite its widespread acceptance, the performance of the index has been criticized. Chief among the concerns has been that the index is not specific for LUTS attributable to BPH.6 Thus, the index cannot be used by itself for diagnosis; however, that was never an intended use, as emphasized by the original validation study.<br>Another longstanding criticism has been that the AUASI does not include an urge incontinence (UI) item, which would also balance the number of filling and voiding items in the index. [7], [8], [9], [10] and [11] Although the original developers considered incontinence a separate domain of LUTS, UI due to secondary detrusor instability can certainly occur among men with bladder outlet obstruction resulting from BPH.<br>The purpose of the present study was to examine the value, especially in terms of predicting symptom-related bother, of adding an UI question to the AUASI among men enrolled in the Complementary and Alternative Medicine for Urological Symptoms (CAMUS) trial.