Fig. 2
Patient disposition. aPatients initiating treatment with both UMEC/VI and TIO on the index date were classified as TIO and subsequently excluded (N = 42); bICD-9/10-CM diagnostic codes for COPD are shown in Additional file 1: Table S1; cModerate COPD-related exacerbations were defined as an outpatient or ER visit with a diagnosis code for COPD in the primary position and ≥ 1 dispensing/administration of a systemic corticosteroid or guideline-recommended antibiotic within 5 days before or after the visit. Severe COPD-related exacerbations were defined as an inpatient hospitalization with a diagnosis code for COPD in the primary position (Additional file 1, Table 1); dICD-9/10-CM diagnostic codes for asthma are shown in Additional file 1: Table S1; eIMT was defined as no ICS-, LABA-, or LAMA-containing maintenance medication prior to the first pharmacy claim for UMEC/VI or TIO during the identification period. COPD, chronic obstructive pulmonary disease; ER, emergency room; ICD-9, International Classification of Diseases 9th Edition; ICD-10, International Classification of Diseases 10th Edition; ICS, inhaled corticosteroids; IMT, initial maintenance therapy; LABA, long-acting β2-agonist; LAMA, long-acting muscarinic antagonist; TIO, tiotropium; UMEC, umeclidinium; VI, vilanterol