BACKGROUNDAsthma is one of the most common chronic respiratory disease states in the United States and poses a large economic burden. The Global Initiative for Asthma updated its clinical guidelines to recommend low-dose inhaled corticosteroids (ICSs)-formoterol as the preferred reliever option in the treatment of asthma. Randomized controlled trials show lower exacerbation rates in patients using an ICS-formoterol inhaler as a reliever compared with patients using a short-acting β2-agonist-based reliever. There are minimal real-world data examining how this update impacts clinical outcomes and costs.OBJECTIVETo evaluate real-world asthma-specific outcomes and costs before and after members adopt a preferred treatment plan aligning with the updated Global Initiative for Asthma guideline recommendations and evidence.METHODSThis retrospective, observational cohort study was performed using claims data for commercially insured members initiating an ICS-formoterol inhaler for asthma. The population included members aged 6-65 years with an asthma diagnosis, 2 or more pharmacy claims for an albuterol inhaler, and 1 or more pharmacy claims for an ICS-formoterol inhaler. The index date was the first pharmacy claim for an ICS-formoterol inhaler. All members were continuously enrolled during the 24-month study period, consisting of a 12-month preperiod and postperiod based on the index date. The primary clinical outcome was mean annual asthma exacerbations. The primary cost outcomes include the difference among mean annual asthma-specific pharmacy, medical, and total costs per member with asthma. A paired Wilcoxon signed rank test was used for statistical analysis.RESULTSClaims for 590 members were included in the analysis. The population consisted of 55.9% women with a mean age of 39 years. The mean annual asthma exacerbations decreased 25.6% from the preperiod to the postperiod (0.347 vs 0.258; P = 0.028). Mean asthma-specific pharmacy and total asthma costs significantly increased from the preperiod to the postperiod $474 vs $1,796 (P < 0.001) and $1,505 vs $2,567 (P < 0.001), respectively. The mean asthma-specific medical costs significantly decreased in the postperiod compared with the preperiod ($1,031 vs $771; P = 0.031).CONCLUSIONSIn this descriptive study, initiators of ICS-formoterol experienced a decrease in asthma exacerbations and an increase in professional visits. Initiators also had higher mean asthma-specific pharmacy and total costs, but lower mean asthma-specific medical costs. Health plans can take additional steps to promote implementation of updated guidelines. Pursuing clinical programs to further reduce asthma exacerbations would benefit members, providers, and the health plan.