Convergent validity and responsiveness of the EQ-5D utility weights for stroke survivors

Abstract

Objective: This prospective study examined the convergent validity and responsiveness of the EuroQoL-5 Dimensions Health Questionnaire (EQ-5D) utility weights in stroke survivors at the subacute stage. Methods: Repeated assessments were conducted in rehabilitation wards of a medical centre. A study cohort was recruited from inpatients (n = 478). A total of 342 participants (71.5%) completed 2 assessments; 1 at ward admission and 1 before hospital discharge. Outcome measures, including the Barthel Index (BI), Patient Health Questionnaire (PHQ-9) and EQ-5D, were administered at ward admission and before hospital discharge. Results: The validity of the EQ-5D utility weights was assessed by comparison with the scores of the BI and PHQ- 9. The absolute values of Pearson correlation coefficients ranged from 0.40 to 0.52 for the association of EQ-5D utility weights with BI scores and PHQ-9 scores at admission and before hospital discharge. The EQ-5D utility weights had a moderate effect size (0.76), moderate standardized response mean (0.74), and a significant difference (paired t-value = 13.7, p < 0.001) between baseline and follow-up in their ability to detect changes in the health status of stroke survivors staying in a rehabilitation ward. Conclusion: This study supports the use of the EQ-5D utility weights as a valid and responsive instrument for performing cost-utility analyses of stroke survivors, including those with higher levels of dependence, at the subacute stage.