Trends in antibiotic use in Massachusetts children, 2000-2009.

OBJECTIVE Antibiotic use rates have declined dramatically since the 1990s. We aimed to determine if, when, and at what level the decline in antibiotic-dispensing rates ended and which diagnoses contributed to the trends. METHODS Antibiotic dispensings and diagnoses were obtained from 2 health insurers for 3- to <72-month-olds in 16 Massachusetts communities from 2000 to 2009. Population-based antibiotic-dispensing rates per person-year (p-y) were determined according to year (September-August) for 3 age groups. Fit statistics were used to identify the most likely year for a change in trend. Rates for the first and last years were compared according to antibiotic category and associated diagnosis. RESULTS From 2000-2001 to 2008-2009, the antibiotic-dispensing rate for 3- to <24-month-olds decreased 24% (2.3-1.8 antibiotic dispensings per p-y); for 24- to <48-month-olds, it decreased 18% (1.6-1.3 antibiotic dispensings per p-y); and for 48- to <72-month-olds, it decreased 20% (1.4-1.1 antibiotic dispensings per p-y). For 3- to <48-month-olds, rates declined until 2004-2005 and remained stable thereafter; the downward trend for 48- to <72-month-olds ended earlier in 2001-2002. Among 3- to <24-month-olds, first-line penicillin use declined 26%. For otitis media, the dispensing rate decreased 14% and the diagnosis rate declined 9%, whereas the treatment fraction was stable at 63%. CONCLUSIONS The downward trend in antibiotic dispensings to young children in these communities ended by 2004-2005. This trend was driven by a declining otitis media diagnosis rate. Continued monitoring of population-based dispensing rates will support efforts to avoid returning to previous levels of antibiotic overuse.