The Dermatology Life Quality Index as the primary outcome in randomized clinical trials: a systematic review.

Background: Primary endpoint measures in clinical trials are typically measures of disease severity, with patient-reported outcome measures (PROMs) relegated as secondary endpoints. However, validation of some PROMs may be more rigorous than that of disease severity measures, which could provide support for a primary role for PROMs.
Objectives: This study reports on 24 peer reviewed journal articles that used the Dermatology Life Quality Index (DLQI) as primary outcome, derived from a systematic review of randomized controlled trials (RCTs) utlizing DLQI, covering all diseases and interventions.
Methods: The study protocol was prospectively published on the PROSPERO database, and the study followed PRISMA guidelines. Searches were made using MEDLINE, The Cochrane Library, Embase, Web of Science, Scopus, CINAHL (EBSCO) and PsycINFO databases and records were combined into an Endnote database. Records were filtered for duplicates and selected based on study inclusion/exclusion criteria. Full-text articles were sourced and data were extracted by two reviewers into a bespoke REDCap database, with a third reviewer adjudicating disagreements. The Jadad scoring method was used to determine risk of bias.
Results: Of the 3220 publications retrieved from online searching, 457 articles met the eligibility criteria and included 198 587 patients. DLQI scores were used as primary outcomes in 24 (5.3%) of these studies comprising 15 different diseases and 3436 patients. Most study interventions (17 of 24 studies, 68%) were systemic drugs, with biologics (liraglutide, alefacept, secukinumab, ustekinumab, adalimumab) accounting for 5 of 25 pharmacological interventions (20%). Topical treatments comprised 32% (8 studies), whereas nonpharmacological interventions (n = 8) were 24% of the total interventions (N = 33). Three studies used nontraditional medicines. Eight studies were multicentred (33.3%), with trials conducted in at least 14 different countries, and four studies (16.7%) were conducted in multiple countries. The Jadad risk of bias scale showed that bias was uncertain or low, as 87.5% of studies had Jadad scores of ≥ 3.
Conclusions: This study provides evidence for use of the DLQI as a primary outcome in clinical trials. Researchers and clinicians can use this data to inform decisions about further use of the DLQI as a primary outcome.
Competing Interests: Conflicts of interest A.Y.F. is joint copyright owner of the Dermatology Life Quality Index (DLQI). Cardiff University receives royalties from some use of the DLQI: A.Y.F. receives a proportion of these under standard university policy. J.R.I. receives a stipend as Editor-in-Chief of the British Journal of Dermatology and an authorship honorarium from UpToDate. He is a consultant for AbbVie, Boehringer Ingelheim, ChemoCentryx, MoonLake, Novartis, UCB Pharma and Union Therapeutics, and has served on advisory boards for Insmed, Kymera Therapeutics and Viela Bio. He is co-copyright holder of Hidradenitis Suppurativa Quality of Life, Investigator’s Global Assessment and Patient’s Global Assessment instruments for hidradenitis suppurativa. His department receives income from royalties from the Dermatology Life Quality Index (DLQI) and related instruments. S.S. has received an unrestricted educational grant from GSK and the Centre for Innovative Regulatory Science, is a consultant for Novo Nordisk and produces educational materials for AbbVie. J.V. participated in an Advisory Board for Amgen, has received payment or honoraria from L’Oreal and support from UCB pharma for attending meetings. F.M.A. has received honoraria from AbbVie, Janssen, LEO Pharmaceuticals, Lilly Pharmaceuticals, L’Oreal, Novartis and UCB. His department receives income from royalties from the DLQI and related instruments. J.R.J. has no conflicts of interest to report. His department receives income from royalties from the DLQI and related instruments.
(© The Author(s) 2024. Published by Oxford University Press on behalf of British Association of Dermatologists.)