Patterns of Asthma Medication Use in New Zealand After Publication of National Asthma Guidelines

Background: In June 2020, the New Zealand (NZ) adolescent and adult asthma guidelines recommended budesonide/formoterol, taken as maintenance and/or reliever therapy, as the preferred therapeutic approach.

Objective: To investigate whether these recommendations were associated with changes in clinical practice indicated by asthma medication use trends.

Methods: NZ national dispensing data for inhaler medications from January 2010 to December 2021 were reviewed. Monthly "dispensings" of inhaled budesonide/formoterol, inhaled corticosteroid (ICS), other ICS/long-acting β₂-agonists (LABA), and inhaled short-acting β₂-agonists (SABA), for the 12+ age group, were displayed graphically with piecewise regression used to produce plots of rates by time with a July 1, 2020, break point. The number of dispensings in the last 6 months that data were available (July-December 2021) was compared with the corresponding period, July-December 2019.

Results: Budesonide/formoterol dispensing increased markedly after July 1, 2020 (regression coefficient 41.1 inhalers dispensed/100,000 population per month [95% confidence interval (CI): 36.3-45.6, P < .0001]; 64.7% increase in the number of dispensings between July-December 2019 and July-December 2021), in contrast to "other ICS/LABA" (regression coefficient: -15.9 [95% CI: -22.2 to -9.6, P < .0001]; -1.7% decrease) and SABA (regression coefficient: -14.7 [95% CI: -29.7 to 0.3, P = .055]; -10.6% decrease), respectively.

Conclusion: In NZ, a progressive increase in budesonide/formoterol dispensing, accompanied by a reduction in SABA and "other ICS/LABA" dispensing, occurred after publication of the 2020 NZ asthma guidelines. While acknowledging the limitations in the interpretation of temporal associations, these findings suggest that the transition to ICS/formoterol reliever-based therapy can be achieved if recommended and promoted as the preferred therapeutic approach in national guidelines.