Adherence to smart inhalers in a clinical trial of preterm-born children

<bold>Introduction:</bold> Previously, we showed that 12-week combined inhaled corticosteroids (ICS) and long-acting beta agonists (LABA), in children aged 7-12 years, born at ≤34 weeks’ gestation, significantly improved FEV1 than ICS or placebo (Goulden, JAMA Ped 2022;176:133-141). We report here the adherence to their study inhalers. <bold>Methods:</bold> The 53 children (mean (SD) aged 10 (1.2) years, mean gestation 29.7 (2.9) weeks) from the RHiNO cohort were given smart inhalers (Adherium, NZ), over the 12-week treatment period, as follows: ICS (n=18), ICS/ LABA (17) and placebo (13) administered as two inhalers, twice daily. The smart inhalers monitored the children's daily dose intake. Data were analysed using ANOVA using SPSS (IBM, US). <bold>Results:</bold> Overall, the mean (SD) adherence were 59.7% (30.1%), 63.7% (21.8%) and 44.1% (27.8%) in the ICS, ICS/LABA and placebo groups respectively. Significant differences were noted between the ICS/LABA vs placebo (p=0.017) but not ICS vs placebo or ICS vs ICS/LABA. The morning adherence was significantly different for ICS/LABA vs placebo (p=0.019) and ICS vs placebo (p=0.039) but not ICS/LABA vs ICS (p=0.938). Only ICS/LABA vs placebo group (p=0.027) was significantly different for evening adherence. Overall differences were noted between boys (mean (SD) 49.0% (30.7%)) and girls (62.1% (25.0%), p=0.025), notably in the ICS group (boys 36.6% (27.6%), girls 74.4% (21.4%), p<0.001). No associations were noted with early/current life factors. Weekly adherence declined over the 12-week treatment period for all groups. <bold>Conclusion:</bold> Although adherence was best in the active treatment groups, it was much lower than the WHO recommended adherence of >80%. Furthermore, it decreased over the 12-week period.