OBJECTIVES

An estimated 12% of children have multiple chronic conditions and are at risk for taking multiple medications for different chronic conditions. Chronic medication burden affects medication adherence. In patients with attention-deficit/hyperactivity disorder (ADHD), poor adherence can result in poor long-term outcomes. We aimed to determine the impact of medication burden on ADHD medication adherence amongst children with multi-morbidity.

METHODS

A retrospective cohort study of children (2-17 years) with multi-morbidity, and incident ADHD medication use was conducted using the Truven Marketscan Research database. Using prescriptions dispensed in the 30 days preceding ADHD medication start, chronic medication burden was defined in two ways: 1) total number of chronic medications and 2) total daily dosing frequency. ADHD medication adherence was measured by proportion of days covered (PDC) over 12-months; PDC ≥0.80 was considered adherent. Adjusted odds ratios (aOR) were estimated using logistic regression to measure the association between medication burden and ADHD medication adherence, controlling for differences across groups.

RESULTS

There were 48,839 children included, with a mean (SD) age of 11 (3.9) years and 62.9% were male. On average, cohort members experienced 2.6 (1.1) chronic medications at baseline. The majority (68.3%) of children were not on any chronic medication, while 20.3% had one and 11.4% had two or more. Overall, 34.6% of children were adherent. In an adjusted model, children with more chronic medications had an increased likelihood of adherence to ADHD medication compared to children without chronic medications (aOR[95%CI] 1 medication=1.11[1.05-1.17]; 2 medications=1.29[1.19-1.40]; 3 medications=1.48[1.30-1.70]; 4+ medications=1.65[1.39-1.96]). Similar findings were observed with the outcome of total daily dosing frequency.

CONCLUSIONS

Amongst children with multi-morbidity, increased medication burden attributes to higher likelihood to adhere to ADHD medications. Overall, adherence was suboptimal in this population. It is important to recognize this phenomenon and implement strategies to improve adherence in an effort to avoid long-term consequences.