Development and validation of the Bladder Cancer Index: a comprehensive, disease specific measure of health related quality of life in patients with localized bladder cancer.

PURPOSE We developed and validated a reliable, responsive multidimensional instrument to measure disease specific health related quality of life in bladder cancer survivors treated with local cancer therapy. MATERIALS AND METHODS Instrument content was based on qualitative information obtained from a panel of bladder cancer providers and from patient focus groups. Draft items were piloted and revised, resulting in the 36-item Bladder Cancer Index consisting of urinary, bowel and sexual health domains. Internal consistency, test-retest reliability, convergent validity, concurrent validity and criterion validity were then assessed. RESULTS Internal consistency was high at 0.77 to 0.91. Test-retest reliability was also high at 0.73 to 0.95. Correlations among the 3 domains were low (r < or = 0.39), indicating interscale independence. Health outcome discrimination was apparent in clinically distinct treatment groups. Moderate correlation was observed with existing external measures, indicating that the Bladder Cancer Index detects aspects of health related quality of life related to bladder cancer treatments that are not recorded by more general measures. CONCLUSIONS The Bladder Cancer Index is a robust, multidimensional measure of bladder cancer specific health related quality of life and to our knowledge is the first available validated instrument to assess health outcomes across a range of local treatments commonly used for bladder cancer.