Measurement Properties of the EQ VAS Around the Globe: A Systematic Review and Meta-Regression Analysis

Objectives: This study aimed to synthesize and evaluate published evidence on the measurement properties of the EQ VAS, a component of all EQ-5D questionnaires. Methods: This systematic review followed the Consensus-Based Standards for the Selection of Health Measurement Instruments guidelines. Five electronic databases were searched for EQ-5D-3L and EQ-5D-5L validation articles published from January 1, 2009, to November 5, 2019. Evidence for construct validity, test-retest reliability, and responsiveness was extracted from individual studies before being aggregated for evaluation of the populations represented by the studied samples. Multivariable logistic meta-regression was conducted to explore the effects of potential covariates on construct validity. Results: A total of 50 articles containing 488 studies, using samples drawn from 12 different populations, were identified. Generally, the quality of evidence was high for construct validity studies (n = 397) but only moderate for both test-retest reliability studies (n = 21) and responsiveness studies (n = 70). "Sufficient" construct validity of EQ VAS was found in 8 of 12 populations, "sufficient" test-retest reliability was found in 3 of 11 populations, and "sufficient" responsiveness was found in 5 of 12 populations. Meta-regression analyses suggested that construct validity studies from the Asian-Pacific region were more likely to show a negative rating compared with studies from Europe and North America. Conclusion: The EQ VAS exhibits "sufficient" construct validity, "inconsistent" test-retest reliability, and "inconsistent" responsiveness across a broad range of populations. Additional studies are needed to explore the suboptimal validity of the EQ VAS in the Asian-Pacific region, whereas more high-quality validation studies are needed to assess its reliability and responsiveness.