Burden of illness and costs associated with eosinophilic granulomatosis with polyangiitis: evidence from a managed care database in the United States

BACKGROUND: Data on the clinical and economic burden of eosinophilic granulomatosis with polyangiitis (EGPA) are limited. OBJECTIVE: To assess the real-world clinical and economic outcomes of patients diagnosed with EGPA vs patients with asthma (present in > 90% of EGPA cases) receiving treatment in the United States. METHODS: This retrospective cohort study (HO-17-17742) used administrative claims data (July 1, 2007-May 31, 2017) from the Optum Research Database. Eligible patients were aged at least 18 years at index (first date that patients met the EGPA or asthma cohort definition), with a minimum of 6 months of continuous health plan coverage before the index (baseline) period and 12 months following and including the index date (follow-up period). Patients with EGPA were identified either via published algorithms using claim code combinations for conditions and medications (before October 1, 2015) or via a claim with the EGPA ICD-10-CM code (M30.1, after October 1, 2015). Patients with asthma were identified based on ICD-9-CM and ICD-10-CM diagnosis codes and at least 3 pharmacy asthmarelated medication claims within a year of diagnosis. Outcomes included all-cause health care costs (primary), all-cause health care resource utilization (HCRU), systemic corticosteroid (SCS) use, and EGPA relapses requiring hospitalization and EGPA-related (based on EGPA-related HCRU) relapses during the follow-up period (all secondary). EGPA and asthma cohorts were matched (1:3) via propensity score matching based on demographic, insurance, and index timing covariates. RESULTS: 8,904 patients were included in the matched EGPA (n = 2,226) and asthma (n = 6,678) cohorts (mean [SD] age: 59.7 [14.2] vs 59.6 [14.7] years; Quan-Charlson Comorbidity Index scores: 1.8 [1.7] vs 0.8 [1.4]). During follow-up, mean (SD) all-cause costs ($49,593 [$88,161] vs $21,122 [$40,110]; P < 0.001), all-cause HCRU (P < 0.001), and the proportion of patients with 1 or more SCS claims (72.3% vs 66.9%; P < 0.001) were significantly greater in the EGPA vs asthma cohorts, respectively. Mean daily SCS dose (43.6-45.5 mg/day) was similar between cohorts; patients with EGPA had significantly (P < 0.001) longer periods taking SCS doses at least 4 mg/day (mean [SD]: 64.9 [95.6] vs 14.6 [39.3] days) and at least 7 mg/day (52.8 [82.0] vs 12.1 [30.6] days). 35.2% (n = 784/2,226) and 44.1% (n = 981/2,226) of patients with EGPA experienced a minimum of 1 EGPA relapse requiring hospitalization, and at least 1 EGPA-related relapse, respectively. Mean (SD) total all-cause costs were greater than 3-fold higher in patients with vs without a relapse requiring hospitalization ($92,825 [$128,562] vs $26,087 [$38,082]; P < 0.001) and for patients with vs without an EGPA-related relapse ($78,081 [$120,775] vs $27,145 [$35,584]; P < 0.001). CONCLUSIONS: Patients with EGPA have more comorbidities, greater health care costs and HCRU, and use SCS more frequently than patients with asthma. Additionally, more than one third of patients with EGPA experienced disease relapses over 12 months. These results highlight the high disease burden in patients with EGPA and the need for improved treatment options.