“…[10][11][12] However, a specific diagnosis code for use in identifying patients with EGPA from health records was only established in the United States in October 2015 with the adoption of the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM); before ICD-10-CM, studies evaluating the burden of EGPA via retrospective analyses of administrative claims data relied on a series of coding algorithms (eg, International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] diagnosis and procedures codes, Current Procedural Terminology [CPT] codes, and physician specialties). [13][14][15][16][17][18] Owing to the previous lack of EGPA-specific diagnosis codes and limited number of regulatory approved treatments, data are limited on the clinical and economic burden of EGPA. Comparing clinical outcomes in EGPA with those in patients with asthma, in which the disease burden is well established, 19 is a useful way to measure the burden of EGPA for patients and payers.…”