RÉSUMÉ
OBJECTIVES: To evaluate the impact of a payor-initiated formulary change in inhaled corticosteroid coverage on lung function in patients with asthma and on provider prescribing practices. This formulary change, undertaken in August 2016 by a Medicaid payor in Kentucky, eliminated coverage of beclomethasone dipropionate, a metered dose inhaler (MDI), in favor of mometasone furoate, available as MDI and dry powder inhaler (DPI). STUDY DESIGN: A retrospective chart review was conducted on children with asthma ages 6-18 years covered by the relevant payor from a university-based pediatric practice who were seen before the formulary change (February to July 2016) and after (February to July 2017). Spirometry data from each visit was compared using the paired Student t test. RESULTS: Fifty-eight patients were identified who were initially on beclomethasone dipropionate and had spirometry available at both visits. Those who switched from an MDI to a DPI (n = 24) saw a decline in median predicted forced expiratory volume in 1 second from 98.5% to 91% (P = .013). A decline was also seen in forced expiratory flow at 25%-75%, from 89.5% predicted to 76% predicted (P = .041). No significant changes were observed in children remaining on an MDI. Seven patients discontinued inhaled corticosteroid therapy. CONCLUSIONS: This study suggests insurance formulary changes leading to use of a different inhaler device may have a detrimental impact on pediatric lung function, which may be a surrogate measure for overall asthma control. This could be due to a lack of adequate timely educational intervention as well as the inability of some children to use DPIs.