Are condition-specific utilities more valid than generic preference-based ones in asthma? Evidence from a study comparing EQ-5D-3L and SF-6D with AQL-5D

ABSTRACT

Background: Systematic discrepancies have been shown in utility values derived from different instruments. This study compares utilities from the condition-specific AQL-5D and the generic EQ-5D-3L and SF-6D in an asthmatic population with heterogeneous health-related quality of life (HRQoL), disease severity, and control status.

Methods: A consecutive sample of 104 patients diagnosed with asthma completed a survey containing the Greek versions of SF-36, EQ-5D-3L, and AQLQ(s). Treatment adequacy was assessed with the Asthma Control Questionnaire (ACQ), and asthma severity according to Global Initiative for Asthma 2016 guidelines. Association and agreement between instruments were assessed with Spearman’s correlation and Bland–Altman plots.

Results: AQL-5D utilities exceeded (p < 0.001) those from EQ-5D-3L and SF-6D. There were weak-to-moderate correlations (<0.5) between most dimensions of AQL-5D, and those of EQ-5D-3L and SF-6D, and strong correlations between similar dimensions of EQ-5D-3L and SF-6D. Significant differences (p < 0.001) were observed throughout the visual analog scale (VAS), asthma severity and asthma control subgroups, with AQL-5D consistently higher than EQ-5D-3L and SF-6D.

Conclusions: All instruments distinguished between differing degrees of asthma control, but only AQL-5D discriminated between asthma severity and HRQoL as well. Although the relatively small sample warrants caution in interpreting the subgroup results, this study contributes to the growing number of comparisons between condition-specific and generic preference-based instruments.

KEYWORDS:

• Utilities
• EQ-5D-3L
• SF-6D
• AQL-5D
• Asthma

Author contributions

NK conceived the study and the methodological design, interpreted the results and prepared the manuscript. ES performed part of the measurements and contributed to the literature review and preparation of the manuscript. AB performed measurements and assisted in the statistical analysis and the literature review. MT conducted the statistical analysis and revised the manuscript for intellectual content. LF interpreted the results, contributed to the statistical analysis and revised the manuscript for intellectual content.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.