EQ-5D health utilities: exploring ways to improve upon responsiveness in psoriasis

Abstract

Aims: To determine if EuroQoL 5-Dimension Health Questionnaire (EQ-5D) health utility scores were able to discriminate among different levels of improvement in psoriasis severity following therapy.

Materials and methods: Data were from three placebo-controlled phase 3 ixekizumab studies (UNCOVER-1, UNCOVER-2, and UNCOVER-3) with patients who had baseline Dermatology Life Quality Index scores >10 (DLQI >10). Psoriasis severity (Psoriasis Area and Severity Index [PASI]), general health utility (EQ-5D), and psoriasis-specific utility (EQ-PSO, UNCOVER-3 only) were assessed. EQ-5D-5L utility scores were generated using the England EQ-5D-5L value set, a crosswalk applied to the EQ-5D-3L United States (US) and United Kingdom (UK) value sets, and a regression-based exploratory scoring function for the EQ-PSO (UK). Analysis of variance was used to estimate change in EQ-5D-5L from baseline to Week 12 per PASI improvement level: PASI <50, PASI 50 to <75, PASI 75 to <90, PASI 90 to <100, and PASI 100. Missing data were imputed using the last observation carried forward method. Value sets for the UK, England, and the US were applied.

Results: In total, 2085 patients across UNCOVER-1, UNCOVER-2, and UNCOVER-3 had baseline DLQI >10 and available utility scores. At Week 12, mean EQ-5D utility scores increased with increasing PASI improvement levels (p < 0.001, all analyses). Mean health utilities for PASI 90 to <100 and PASI 100 were similar when based on the generic classifier, whereas a clear differentiation between PASI 90 to <100 and PASI 100 was observed for EQ-PSO mean scores (UNCOVER-3 only, n = 645; PASI 90 to <100: 0.141, PASI 100: 0.200; adjusted p = 0.043).

Limitations: EQ-5D-5L index-based scores have limited ability to differentiate among psoriasis patients at the highest PASI improvement levels.

ConclusionsL Adding psoriasis-specific EQ-PSO dimensions to the EQ-5D may enhance responsiveness to improvement in skin clarity at the highest PASI levels, and, therefore, generate utility scores that better reflect treatment benefit in cost-utility models.

Keywords:

• EQ-5D
• Health utility
• Cost utility
• Psoriasis
• Quality-of-life

Transparency

Declaration of funding

This research was funded by Eli Lilly and Company and/or one of its subsidiaries. (UNCOVER-1, UNCOVER-2, and UNCOVER-3 ClinicalTrials.gov numbers NCT01474512, NCT01597245, and NCT01646177, respectively).

Declaration of financial/other relationships

JME peer reviewers on this manuscript have no relevant financial or other relationships to disclose. ASP is partner at Second City Outcomes Research LLC, which provides health outcomes related consulting services, and is a member of the EuroQol Group, developers of the EQ-5D. MG has been an investigator, a speaker, on an advisory board for AbbVie, Amgen, Boehringer Ingelheim, Celgene, Eli Lilly, Galderma, Janssen, Leo Pharma, Novartis, and Pfizer, and investigator for Dermira, UCB, and Coherus. SH and CN are employees and stockholders of Eli Lilly and Company Ltd.

Acknowledgments

The authors would like to thank Kelly Guerrettaz, inVentiv Health Clinical (Princeton, NJ) for her assistance with the manuscript writing, and Russel Burge, Eli Lilly and Company (Indianapolis, IN) for his assistance with the development of the manuscript.