Validity and Responsiveness of EQ-5D in Asthma: A Systematic Review and Meta-analysis.

Objective: We aimed to synthesize the evidence on the construct validity and responsiveness of the EQ-5D and compare them with asthma-specific health-related quality-of-life scales, to guide further research and clinical applications in asthma.

Methods: We searched key databases from inception to 1 June, 2024 and used the COnsensus-based Standards for the Selection of Health Measurement Instruments (COSMIN) method to appraise the evidence. The effect size estimates were aggregated using the inverse variance method to evaluate the relative efficiency of EQ-5D measures against the Asthma Quality of Life Questionnaire (AQLQ) and/or its corresponding preference-based index, Asthma Quality of Life-5 Dimensions (AQL-5D).

Results: There were 493 tests (construct validity: 428; responsiveness: 65) drawn from 37 selected articles (validation: 7; clinical: 30). Overall, 78.4% and 76.9% of the a priori hypotheses for assessing construct validity (convergent validity: 56.4%; known groups: 88.5%) and responsiveness, respectively, were satisfied. The methodological quality was "very good" or "adequate" in 78.2% of construct validity tests and 92.3% of responsiveness tests. The pooled correlation coefficient between EQ-5D index and AQLQ total scores was 0.52 (95% confidence interval 0.43-0.59), and between EQ visual analog scale and AQLQ total scores was 0.53 (95% confidence interval 0.34-0.69). The Cohen's d ratios for the index, level sum scores, and visual analog scale compared to AQLQ were 0.56 (n = 27), 1.16 (n = 16), and 0.75 (n = 37). The EQ-5D index's Cohen's d ratio compared to AQL-5D was 0.49 (n = 5). The standardized response mean ratios for the index and visual analog scale compared to AQLQ were 0.26 (n = 11) and 0.63 (n = 9).

Conclusions: The EQ-5D demonstrated overall good validity and responsiveness in the adult asthma population. However, a comparison against disease-specific instruments suggested scope for improvement in its psychometric performance for this population.