BACKGROUND/PURPOSE: To better understand the available economic evaluations in eosinophilic granulomatosis with polyangiitis (EGPA), a systematic literature review was undertaken. The primary objective of this review was to collect economic evidence including economic evaluations and models, cost-utility analyses, utility studies, and prospective and retrospective studies reporting costs or resource utilisation for patients treated for EGPA. Secondary objectives were to explore the natural history of EGPA.
METHODS: The review was undertaken to meet the requirements of the National Institute for Health and Care Excellence (NICE), the Centre for Reviews and Dissemination's Guidance for Undertaking Reviews in Health Care, the Cochrane Collaboration, and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting methods. Searches were conducted in electronic databases (PubMed, Embase, Cochrane, BIOSIS, Econlit); conference abstracts (ISPOR; EULAR; ACR), and key international health technology assessment websites. Searches were not limited by date, language, or geographical location. Quality assessments were conducted on economic evaluations using the Drummond checklist in line with NICE requirements. Quality assessments were not conducted for other types of economic evidence.
RESULTS: The databases yielded a total of 2,055 titles (439 duplicates), internet searches yielded 335, and hand-searching 12. After initial screening of abstracts, a total of 294 publications were progressed for further screening leaving 85 articles deemed acceptable for data extraction. Of the 85 studies identified: - Only a single economic evaluation was identified which had limited applicability to the research question as it focused on the cost-effectiveness of pneumonia prophylaxis in Wegener’s granulomatosis (WG); - 31 studies reported health related quality of life or symptom burden outcomes (17 reported SF-36 Health Survey (SF-36), 4 reported Health Assessment Questionnaire (HAQ) outcomes, and 1 reported EQ-5D outcomes); - 22 reported cost and resource-use outcomes (14 studies reported medication usage, 9 studies reported productivity lost, 4 studies reported on impact of disease on income, 3 studies reported resource use, 2 reported overall cost, and 1 study reported medication costs); - 45 natural history studies were identified (18 reported the outcome ‘achieved remission’, and 26 reported relapse rates. 34 of the studies reported all-cause mortality; 14 studies reported EGPA-related mortality).
CONCLUSION: This systematic literature review has identified many gaps in the literature regarding EGPA and its treatments, particularly in economic evaluations. This is perhaps not surprising, given that EGPA is a rare disease with limited treatment options. Of the studies identified there was a considerable amount of heterogeneity. The lack of standardised data collection methods makes the synthesis of economic evidence in EGPA challenging.
