OBJECTIVES: No study has evaluated the impact of any intervention on changes in health state utility values (HSUVs) and health-related quality of life over time among caregivers. The aims of this study were to assess HSUVs in caregivers of elderly patients, depending on whether they received social worker support, and to investigate the time-to score deterioration (TTD) as well as factors associated with change in HSUVs.

METHODS: The multicentre open-label ICE study (Pozet et al.) included caregivers of elderly patients with chronic diseases, randomly assigned (1:1 ratio) to either the supportive intervention group (SIG), receiving an informational booklet and social worker intervention, or the control group (CG) receiving only the booklet. HSUVs were assessed at baseline, 6, 12, 18 and 24 months using EQ-5D-3L utility index scores and exploring their TTD and its 95% confidence interval. Factors associated with change in HSUVs were analysed in a 2-step approach, using univariate Cox proportional hazards regression model followed by a multivariate model.

RESULTS: Among 179 included caregivers, the percentage reporting some or extreme problems on five EQ-5D-3L dimensions remained almost stable over time. Median EQ-5D-3L utility index score was 0.89 [0.80-1.00] at baseline (n=177), 0.80 [0.80-0.89] at M6 (n=125) and 0.80 [0.73-0.91] at M24 (n=81). Sixty-two percent of respondents (n=109) experienced a deterioration in EQ-5D-3L utility index score with a median TTD of 9.1 months [6.2-14.9] in the CG and 9.5 months [6.3-14.4] in the SIG (hazard ratio=1.06 [0.73-1.54], p-value=0.76). In multivariate analysis, caregiver professional situation was the only independent predictor of TTD (p-value=0.03).

CONCLUSIONS: Our study provides a HSUVs catalog across different caregiver profiles and at various follow-up timepoints, which can inform future economic evaluations. Caregivers on sick leave, unemployed or job training had statistically significantly longer TTD in comparison with retired or professionally active caregivers.