The first generic maintenance inhaler to receive Food and Drug Administration (FDA) approval was the Wixela Inhub (fluticasone-salmeterol), which came onto the market in February, 2019. The brand-name product, Advair Diskus (fluticasone-salmeterol), has been used for many years to treat both asthma and chronic obstructive pulmonary disease (COPD). This project will include new users of Wixela and Advair Diskus with a diagnosis of COPD who are over the age of 40. The primary effectiveness outcome will be first moderate or severe COPD exacerbation; the primary safety outcome will be first pneumonia hospitalization. Secondary outcomes will include the annual rate of total moderate or severe COPD exacerbations (analyzed separately and together), first moderate exacerbation, first severe exacerbation, annual rate of total pneumonia hospitalizations, and non-persistence.