To assess the responsiveness of the EuroQol (EQ-5D) by comparing it with the Functional Living Index-Cancer (FLIC) and a self-reported rating of health-related quality of life (HRQL).
HRQL was measured four times during the course of high dose chemotherapy (HDC) and bone marrow transplantation in 40 patients with stage II and III breast cancer. Measurements were at baseline (T1), pre-HDC (T2), 3 weeks post-HDC (T3), and 3 months post-HDC (T4).
Effect size ranged from 1.16 (T1-T3) to 0.66 (T3-T4) for the EQ-5D and 0.85-0.91 respectively for the FLIC. No significant differences in effect sizes between the EQ-5D and the FLIC were found. Repeated measures ANOVA yielded a significant change for all measures, with HRQL decreasing post-HDC and returning to baseline levels by 3 m post-HDC. EQ-5D dimensions changed significantly over time for mobility, self-care, and usual activities. EQ-5D index scores at T3 had a bimodal distribution. Interpretation of psychological changes was facilitated by an analysis of FLIC items.
The EQ-5D is responsive to the clinically large changes associated with HDC in breast cancer patients. The bimodal distribution of the EQ-5D index has implications for the interpretation of EQ-5D change scores.