Compared with normal weight children with asthma, overweight children with asthma are less likely to initiate maintenance therapy and less likely to adhere to therapy even when prescriptions are filled, according to a study published in the Journal of Asthma.

Poor control is common in patients with the pediatric obese-asthma phenotype. This historical cohort study (n=311) was designed to determine if weight is associated with treatment nonadherence in children prescribed new maintenance therapies for asthma. The cohort was constructed from a pediatric asthma database that links individual clinical and prescription data on children (ages 2-18) who visited the Montreal Children’s Hospital’s Asthma Center in Canada between 2000 and 2007 to Quebec’s prescription claims registry.

The database has a range of sociodemographic and clinical information, including height and weight, control indicators, asthma severity, morbidity, spirometry test results, phenotype, respiratory comorbidities, environmental exposures, and maintenance therapies prescribed. Primary nonadherence was defined as not claiming prescriptions and secondary nonadherence was measured by the proportion of prescribed days covered (≤50%) during a 6-month follow-up period. The effect of excess weight (body mass index >85th percentile) on nonadherence was estimated using a modified Poisson regression model.

The prevalence of primary and secondary nonadherence in normal-weight participants was 27% and 57%, respectively. The prevalence of primary and secondary nonadherence in participants with excess weight was 29% and 66%, respectively. Excess weight was associated with a trend toward increased risk for primary nonadherence in participants newly prescribed low-dose inhaled corticosteroids (ICS; relative risk [RR], 1.53; 95% CI, 0.94-2.49), but not leukotriene receptor antagonists (LTRA; RR 1.04; 95% CI, 0.24-4.48), medium/high-dose ICS (RR, 0.92; 95% CI, 0.50-1.70), or combination therapies (RR, 0.73; 95% CI, 0.37-1.45). Excess weight was associated with a trend toward increased average risk for secondary nonadherence for all treatments (RR, 1.09; 95% CI, 0. 92-1.30), and more specifically in participants initiating medium/high-dose ICS (RR, 1.24; 95% CI, 0.98-1.59) and combination therapy (RR, 1.07; 95% CI, 0.84-1.37). Secondary nonadherence to low-dose ICS and LTRA were on average lower in children with excess weight (RR, 0.63; 95% CI, 0.39-1.82; and RR, 0.60; 95% CI, 0.25-1.46, respectively).

The investigators concluded that, “Further larger research studies are warranted to confirm our findings in different age groups and to explore the behavioral and treatment-associated factors that may differentially lead to poorer asthma medication adherence, and ultimately worse clinical outcomes, in children with excess weight compared to their normal weight counterparts.”

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Disclosures: One author reports receiving funding from multiple pharmaceutical companies. Please see the reference for complete disclosure information.

Reference

Longo C, Bartlett G, Schuster T, Ducharme FM, MacGibbon B, Barnett TA. Weight status and nonadherence to asthma maintenance therapy among children enrolled in a public drug insurance plan [published online March 26, 2019]. J Asthma. doi:10.1080/02770903.2019.1590593