Factors associated with non-adherence to inhaled corticosteroids for asthma during pregnancy.

Abstract Background Non-adherence is common among pregnant women prescribed inhaled corticosteroids (ICS) for asthma, and may have serious consequences for mother and baby. Factors associated with ICS non-adherence have not been determined in this population. Objectives To determine factors associated with 1) non-adherence to ICS in early-mid pregnancy (cross-sectional) and 2) persistent non-adherence to ICS during pregnancy (longitudinal). Methods Data utilised come from three prospective studies (2004-2019) involving women with asthma recruited by 23 weeks gestation (N=1,614). Demographics, asthma history and current symptoms were assessed, and spirometry was performed at baseline and throughout pregnancy. Women self-reported current medication use and number of ICS doses missed in the past week. Non-adherence was defined as ≥20% of prescribed dosages missed in the past week (baseline) and on at least two occasions during follow-up (persistent). Factors associated with ICS non-adherence were examined using backward stepwise logistic regression. Results Of 610 (38%) women prescribed ICS at baseline, 236 (39%) were classified as non-adherent. Of 612 (38%) women prescribed ICS during at least two follow-up visits, 149 (24%) were classified as persistent non-adherent. Factors associated with non-adherence at baseline were current or ex-smoking, non-Caucasian/non-Indigenous ethnicity, adult diagnosis of asthma, and lower lung function. Factors associated with persistent non-adherence to ICS were lower maternal age, higher parity and no prescribed ICS at baseline. Conclusion Young multiparous non-Caucasian/non-Indigenous mothers are at increased risk of being non-adherent to ICS during pregnancy. Strategies to improve ICS non-adherence should address maternal smoking and target women who (re-)initiate ICS use in pregnancy.