Health-related quality of life in Denmark on a relative scale: mini-catalogue of mean EQ-5D-3L index scores for 17 common chronic conditions
In health economic evaluations the quality-adjusted life-year (QALY) is one of the preferred outcome measures. Catalogues of median-based decrements in EQ-5D-3L index scores for chronic conditions exist to inform economic evaluations but may not be appropriate for this purpose as mean, rather than median, EQ-5D-3L index scores are of primary interest. Firstly, we aim to estimate mean decrements in EQ-5D-3L index scores through a simple stratified analysis as an alternative to regression modelling. In addition, we aim to estimate the mean decrement in EQ-5D-3L index scores in percent relative to a disease-free reference population. Secondly, we aim to handle both multiple imputation and appropriate estimation of standard errors in the presence of individual sampling weights. Data on EQ-5D-3L from the National Health Profile, Denmark, 2013, were used to estimate the EQ-5D-3L index scores. Calculation of decrements in EQ-5D-3L index scores of chronic conditions was done while controlling for the additional number of chronic conditions beside the one in question, age and sex. Also, a test of homogeneity of decrements across subgroups was conducted. We provide a mini-catalogue of new percentage-scale decrements in EQ-5D-3L index scores. For example, we estimated that angina was associated with an 8.2% reduction in the EQ-5D-3L index score compared to a reference group without angina. If the mean EQ-5D-3L score was 0.848 among corresponding groups without angina; angina patients would have an EQ-5D-3L index score of (1-0.082)·0.848=0.778 using the percentage-scale. The estimated percentage reduction in the EQ-5D-3L index score was homogenous regardless of the number of additional chronic conditions, age and sex. We suggest a percentage-scale estimation of EQ-5D-3L index scores for chronic disorders as an alternative to existing median-based methods. Our estimates stem from a simpler model, which, we argue, is easier to use and interpret.
Published: Online May 2016. In print August 2016.
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