Elsevier

Value in Health

Volume 21, Issue 9, September 2018, Pages 1090-1097
Value in Health

Methodology
Minimally Important Difference of the EQ-5D-5L Index Score in Adults with Type 2 Diabetes,☆☆

https://doi.org/10.1016/j.jval.2018.02.007Get rights and content
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Abstract

Background

The EuroQol five-dimensional questionnaire (EQ-5D) is a generic preference-based measure of health-related quality of life, and several studies have made attempts to estimate the minimally important difference (MID) for the EQ-5D index score.

Objectives

To estimate the MID of the five-level EQ-5D (EQ-5D-5L) index score in a population-based sample of adults with type 2 diabetes and to explore whether the MID estimate varies by baseline index score and the direction of change in health status.

Methods

We used longitudinal survey data of adults with type 2 diabetes in Alberta, Canada. The EQ-5D-5L MID was estimated first by the instrument-defined approach, which used the difference between the baseline index scores and the index scores of simulated single-level transitions, and then by the anchor-based approach, which categorized 1-year changes in depressive symptoms, diabetes-related distress, as well as physical and mental health functioning into no change, small change, and large change groups, wherein the MID was estimated as the average change in index score of the small change group.

Results

Using the instrument-defined approach, MID estimates were 0.043, 0.040, and 0.045, whereas anchor-based MID estimates were 0.042, 0.034, and 0.049 for all change, improvement, and deterioration, respectively. Larger MID estimates were observed for lower baseline index scores and for deterioration in health status.

Conclusions

MID estimates of the EQ-5D-5L index score were consistent between instrument-defined and anchor-based approaches and ranged between 0.03 and 0.05. Estimates varied by baseline index score and the direction of change, with similar results for patient subgroups.

Keywords

EQ-5D-5L
health state preference
minimally important difference
type 2 diabetes

Cited by (0)

Conflicts of interest: J. A. Johnson, A. Ohinmaa, and F. Al Sayah are members of the EuroQol Group.

☆☆

This article was presented as a poster at the International Society for Quality of Life Research 23rd Annual Conference and the International Society for Pharmacoeconomics and Outcomes Research 22nd Annual International Meeting.