Recurrent Antibiotic Use in Kentucky Children With 6 Years of Continuous Medicaid Enrollment

Background: Little is known about the distribution of antibiotic use in individual children over time. The amoxicillin index is a recently proposed metric to assess first-line antibiotic prescribing to children. Methods: We constructed a cohort of continuously enrolled Medicaid children using enrollment claims from 2012 to 2017. Pharmacy claims were used to identify antibiotic prescription data. Results: Among 169 724 children with 6 years of Medicaid enrollment, 10 804 (6.4%) had no antibiotic prescription claims during the study period; 43 473 (25.6%) had 1-3 antibiotics; 34 318 (20.2%) had 4-6 antibiotics; 30 994 (18.3%) had 7-10; 35 018 (20.6%) had 11-20; and 15 117 (8.9%) children had more than 20 antibiotic prescriptions. Overall, the population had a median total of 6 antibiotic prescriptions during the study period, but use was higher in certain patient groups: younger age (8 antibiotic fills over the 6-year period, [IQR 4-14]), White children (7 [IQR 3-13], compared to 3 [IQR 1-6] in Black children), rural settings (9 [IQR 4-15]) and chronic conditions (8 [IQR 4-15]). Higher-use groups also had lower rates of amoxicillin fills, reported as amoxicillin indices. Conclusions: Antibiotic use is common among most children insured by Kentucky Medicaid. A number of fills over time were higher in younger children, and in White children, children living in rural settings and children with chronic conditions. Patients with higher recurrent antibiotic use are important targets for designing high-impact antibiotic stewardship efforts.