Urdu Translation and Linguistic Validation of the Bladder Cancer Index Questionnaire.

Background This study aimed to translate the Bladder Cancer Index (BCI) questionnaire to Urdu and validate it to assess the quality of life of patients with bladder cancer. Material and methods After forward and backward translation of the BCI questionnaire into Urdu, content validity was calculated using the content validity index (CVI) based on input from five health experts regarding the clarity and relevance of the questionnaire. Construct validity was measured by comparing the inter-scale domains and subdomains of BCI and by comparing BCI with Short Form 36 (SF-36) using correlations. For assessment of reliability, Cronbach's alpha was calculated to measure internal consistency and for test-retest reliability, the questionnaire was re-administered four weeks later and the correlation of responses at baseline and at a four-week time point was evaluated. Results The questionnaire has good content validity for clarity (0.91) and relevance (0.87). The construct validity of BCI was also adequately displayed by moderate to high correlation between different subdomains of BCI (Pearson's r: urinary - 0.62, bowel - 0.78, sexual function - 0.43) and low to moderate correlation between responses of BCI compared with SF-36 (Pearson's r mostly >0.45). Test-retest reliability was excellent (Pearson's r 0.90-0.98), and there was good internal consistency (Cronbach's alpha 0.79-0.92) in the different domains of the questionnaire. Conclusion The Urdu-translated BCI is a valid and reliable tool to measure the impact of bladder cancer on the quality of life of patients.