Adherence to inhaled corticosteroids prescribed once vs twice daily in children with asthma.

Background: Suboptimal adherence to inhaled corticosteroids (ICS) is associated with poor asthma control. Adult studies suggest that simplification of ICS regimen leads to better adherence.

Objective: We aimed to determine whether once-daily, compared with twice-daily, ICS dosing was associated with better adherence among children with asthma.

Methods: We conducted a retrospective observational study of children with asthma prescribed with either once-daily or twice-daily ICS monotherapy between 2011 and 2019. Our primary adherence outcome was the proportion of prescribed days covered (PPDC)-that is, the number of days for which the drug was dispensed by the pharmacy divided by the number of days for which it was prescribed. The impact of once-daily vs twice-daily ICS regimen on adherence was evaluated using linear multivariable regression analysis adjusting for covariates. Secondary outcomes included the proportion of patients with greater than or equal to 75% adherence analyzed using logistic regression models.

Results: A total of 232 children (61% boys; mean age of 5.8 [3.6] years) were included; 120 children were prescribed once-daily, and 112 twice-daily, ICS. The median PPDC was 66.8% for the once-daily and 57.9% for the twice-daily group (P = .03). Children prescribed once-daily ICS had a 7.2% (95% confidence interval, 1.3-13.1) greater mean PPDC compared with the twice-daily group and greater odds of having PPDC greater than or equal to 75% (71.4% vs 45.5%; odds ratio, 1.80; 95% confidence interval, 1.01-3.26).

Conclusion: Our findings suggest that once-daily dosing of ICS is associated with better medication adherence than twice-daily dosing. Whether the gain in adherence leads to better asthma control and health outcomes remains to be evaluated.