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

ABSTRACT

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.

Measuring the quality of life (QoL) of people with skin diseases during controlled studies is normally done by groups of researchers and clinicians. To determine how much a skin disease affects a person's QoL, information on the patient and the severity of their skin condition is collected using laboratory measurements, and/or looking at the skin. Asking patients to self-report the impact of their skin condition using questionnaires they have completed themselves has usually been of secondary importance, even though these questionnaires can often be much more reliable. However, patient-reported outcomes are now being used more often as primary measures in controlled studies. Self-report measures can provide information on how effective treatment is, which can help government agencies to approve new products and justify claims made by drug companies. This study reports on 24 academic studies that used the Dermatology Life Quality Index (DLQI) (a type of self-report measure for dermatology patients) as a primary tool of measurement in controlled trials for a range of different skin diseases and treatments. Our study findings are important, as researchers and clinicians can use this data to help make decisions regarding use of the DLQI.