Psychometric characteristics of a condition-specific, health-related quality-of-life survey: the FACT-Vanderbilt Cystectomy Index

Abstract

Objective: Radical cystectomy (RC) for bladder cancer can be associated with significant morbidity and alterations in health-related quality of life (HRQOL). The Functional Assessment of Cancer Therapy--Vanderbilt Cystectomy Index (FACT-VCI) is a condition-specific HRQOL survey for patients undergoing RC and urinary diversion (UD) for bladder cancer. This study evaluates the reliability, validity, and responsiveness of the Vanderbilt cystectomy index (VCI).

Methods: The FACT-VCI was administered to patients with bladder cancer undergoing RC and UD (n = 190) at 2 major cancer centers. Statistical methods included principal components analysis, Cronbach's coefficient alpha, and nonparametric correlation coefficients. The Functional Assessment of Cancer Therapy--General (FACT-G) was used to test criterion-related validity and a linear mixed model tested the effects of time and diversion type on longitudinal VCI scores.

Results: A single summary score of 15 gender-neutral items (VCI-15) represented the optimum solution for postoperative data, which was internally consistent (α = 0.85), had strong retest reliability (ρ = 0.891), and was associated with all FACT-G scales and total score (ρ ≥ 0.38, P <.001). Preoperatively, the VCI-15 was internally consistent (α = 0.77) and was associated with the FACT-G physical and functional scales and total score (ρ ≥ 0.41, P <.001). Although VCI-15 scores at postoperative year 1 did not differ from preoperative values overall (P = .145), they did differ by diversion type (P = .027), with no substantive change after orthotopic neobladder (40 ± 9 vs 39 ± 10) but with a clinically significant improvement after an ileal conduit (39 ± 11 vs 44 ± 11).

Conclusion: The VCI-15 is a reliable and valid condition-specific HRQOL survey for patients with bladder cancer undergoing RC and UD. Future studies of RC patients should measure HRQOL using validated, condition-specific forms, such as the FACT-VCI.