A systematic review of the validity and responsiveness of EQ-5D and SF-6D for depression and anxiety

Background: Generic preference based measures (PBM) such as the SF-6D and EQ-5D are increasingly used to inform health care resource allocation decisions. They aim to be generic in the sense of being applicable to all physical and mental health conditions. However, their applicability has not been demonstrated for all mental health conditions.

Aims: To assess the construct validity and responsiveness of EQ-5D and SF-6D measures in depression and anxiety.

Method: A systematic review of the literature was undertaken. Eleven databases were searched in December 2010 and reference lists scrutinised to identify relevant studies. Studies were appraised and data extracted. A narrative synthesis was performed of the evidence on construct validity including known groups validity (detecting a difference in PBM scores between different groups such as different levels of severity of depression), convergent validity (strength of association between generic PBM and other outcome measures) and responsiveness (the ability to detect relevant health changes in health status and the absence of change where there is none).

Results: 26 studies were identified that provided data on the validity and/or responsiveness of the EQ-5D and SF-6D. Both measures demonstrate good construct validity and responsiveness for depression. One study, however, suggests EQ-5D may lack responsiveness in the elderly. These measures are more highly correlated with depression scales in patients with anxiety than they are clinical anxiety scales suggesting known group validity in patients with anxiety may be driven by aspects of depression within anxiety disorder and the presence of co-morbid depression. Direct comparisons between the measures find that the EQ-5D gives lower utility levels for severe depression hence greater health improvement for this group and SF-6D shows more sensitivity to mild depression and performs better in terms of ES and SRM. The comparison between EQ-5D and SF-6D is similar to that found in other conditions.

Conclusion: The evidence base supports the use of EQ-5D and SF-6D in patients with depression and anxiety. More work is needed on the true utility level for severe depression.