Clinical Assistant Professor CHU Sainte-Justine/Université de Montréal CHU Sainte-Justine Montreal, Quebec, Canada
Background: Suboptimal adherence to inhaled corticosteroids (ICS) leads to poor asthma control. Adult studies suggest that simplification of ICS regimen leads to better adherence, but pediatric data are lacking.
Objective: We aimed to determine whether once-daily dosing of ICS, compared to twice-daily dosing, was associated with better adherence among children with asthma and whether these two dosing regimens differed in subsequent asthma control.
Design/Methods: We conducted a retrospective single-center observational study of children with asthma prescribed either once-daily or twice-daily ICS monotherapy, with hydrofluoroalkane-adjusted daily dose of 200-500 mcg. Our primary adherence outcome was the proportion of prescribed days covered (PPDC), i.e. number of days for which the drug was dispensed by the pharmacy divided by the number of days for which the drug was prescribed, expressed in percentage. The impact of ICS dosing regimen (once-daily vs. twice-daily) on adherence was examined using linear multivariate analysis adjusting for covariates. Secondary outcomes included proportion of patients with ≥75% adherence, asthma control (measured by the validated 4-level Pharmacoepidemiologic Pediatric Asthma Control Index), and time to first exacerbation. Multivariable regression models were adjusted for baseline asthma control, asthma phenotype (episodic vs. persistent), as well as age of the patient, and socio-economic status.
Results: A total of 232 patients met inclusion criteria; 120 in the once-daily group and 112 in the twice-daily group. Median PPDC was 77.7% for the once-daily group and 70.4% in the twice-daily group (p=0.03). In multivariable analysis, children prescribed once-daily ICS had a 7.2% (95% C.I. 1.3, 13.1) higher mean PPDC compared to the twice-daily group. They also displayed higher odds of having PPDC ≥75% (Odds ratio 1.80, 95% C.I. 1.01, 3.26). Children prescribed once daily did not have a statistically significant higher odds of being controlled or partially controlled asthma (vs. poor control) compared to twice-daily dosing (OR 1.54, 95% CI: 0.95, 2.51). Finally, time to first exacerbation was not statistically different between children in once-daily group vs. twice-daily (Hazard ratio 0.64, 95% CI 0.35, 1.18). Conclusion(s): Children with once-daily dosing of ICS have better medication adherence than those with twice-daily dosing. Larger studies are needed to confirm whether this gain in adherence leads to better asthma control and health outcomes.
Authors/Institutions: Olivier Drouin, CHU Sainte-Justine, Montreal, Quebec, Canada; Anna Smyrnova, Centre Hospitalier Universitaire Sainte-Justine Centre de Recherche, Montreal, Quebec, Canada; Natalie Betinjane, Centre Hospitalier Universitaire Sainte-Justine Centre de Recherche, Montreal, Quebec, Canada; Francine M. Ducharme, University of Montreal, Montreal, Quebec, Canada