Responsiveness of the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI)

Published in: Quality of Life Research, v. 15, no. 2, Mar. 2006, p. 299-305

Posted on RAND.org on January 01, 2006

by Kathleen Joy Propert, Mark Litwin, Y. Richard Wang, Richard B. Alexander, Elizabeth A. Calhoun, J. Curtis Nickel, Michael P. O'Leary, Michel A. Pontari, Mary McNaughton-Collins

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OBJECTIVES: The NIH-Chronic Prostatitis Symptom Index (NIH-CPSI) was developed to assess symptoms and quality of life in men with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). The authors assessed the responsiveness of the NIH-CPSI to change over time and defined thresholds for changes perceptible to patients. METHODS: The authors studied 174 men with CP/CPPS who participated in a placebo-controlled randomized clinical trial. Changes from baseline to six weeks in the NIH-CPSI total score and pain, urinary, and quality of life subscores were compared to a global response assessment (GRA). Effect sizes and Guyatt statistics were calculated to evaluate responsiveness; 95% confidence intervals were produced using bootstrapping. RESULTS: All scores decreased over time with the largest decrease in subjects who reported on the GRA that they were markedly improved. The NIH-CPSI total, pain, and quality of life scores were highly responsive in the improved groups; the urinary score showed minimal responsiveness. There was no evidence of responsiveness among those subjects who worsened on the trial. ROC curves identified a 6-point decline in the NIH-CPSI total score as the optimal threshold to predict treatment response. CONCLUSIONS: The NIH-CPSI total score and pain and quality of life subscores are responsive to change over time.

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