title: Bladder cancer index: cross-cultural adaptation into Spanish and psychometric evaluation.
abstract: BACKGROUND
  The Bladder Cancer Index (BCI) is so far the only instrument applicable across all bladder cancer patients, independent of tumor infiltration or treatment applied. We developed a Spanish version of the BCI, and assessed its acceptability and metric properties.
  
  
  METHODS
  For the adaptation into Spanish we used the forward and back-translation method, expert panels, and cognitive debriefing patient interviews. For the assessment of metric properties we used data from 197 bladder cancer patients from a multi-center prospective study. The Spanish BCI and the SF-36 Health Survey were self-administered before and 12 months after treatment. Reliability was estimated by Cronbach's alpha. Construct validity was assessed through the multi-trait multi-method matrix. The magnitude of change was quantified by effect sizes to assess responsiveness.
  
  
  RESULTS
  Reliability coefficients ranged 0.75-0.97. The validity analysis confirmed moderate associations between the BCI function and bother subscales for urinary (r = 0.61) and bowel (r = 0.53) domains; conceptual independence among all BCI domains (r ≤ 0.3); and low correlation coefficients with the SF-36 scores, ranging 0.14-0.48. Among patients reporting global improvement at follow-up, pre-post treatment changes were statistically significant for the urinary domain and urinary bother subscale, with effect sizes of 0.38 and 0.53.
  
  
  CONCLUSIONS
  The Spanish BCI is well accepted, reliable, valid, responsive, and similar in performance compared to the original instrument. These findings support its use, both in Spanish and international studies, as a valuable and comprehensive tool for assessing quality of life across a wide range of bladder cancer patients.
authors: Stefanie
authors: S
authors: Schmidt
authors: Ricard
authors: R
authors: Riel
authors: Albert
authors: A
authors: Frances
authors: José Antonio
authors: JA
authors: Lorente Garin
authors: Xavier
authors: X
authors: Bonfill
authors: María José
authors: MJ
authors: Martinez-Zapata
authors: Maria
authors: M
authors: Morales Suarez-Varela
authors: Javier
authors: J
authors: dela Cruz
authors: José Ignacio
authors: JI
authors: Emparanza
authors: María-José
authors: MJ
authors: Sánchez
authors: Javier
authors: J
authors: Zamora
authors: Juan Manuel Ramos
authors: JM
authors: Goñi
authors: Jordi
authors: J
authors: Alonso
authors: Health Services Research Group, IMIM (Hospital del Mar Medical Research Institute), Doctor Aiguader 88, 08003 Barcelona, Spain. mferrer@imim.es.
authors: Montse
authors: M
authors: Ferrer
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D003431:Cross-Cultural Comparison; D005062:European Union; D005260:Female; D006801:Humans; D007802:Language; D008297:Male; D009367:Neoplasm Staging; D011594:Psychometrics / Q000592:standards*; D011788:Quality of Life / Q000523:psychology*; D011795:Surveys and Questionnaires; D014175:Translating; D014481:United States; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis / Q000523:psychology*