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

Objective: 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.

Methods: 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.

Results: 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).

Conclusion: 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.