OBJECTIVES: To assess treatment patterns and treatment-related costs of acute otitis media (AOM) in a Managed Care population. METHODS: All subjects diagnosed with AOM in PharMetrics’ Integrated Outcomes Database between January 1, 1997 and December 31, 1998 were eligible for inclusion. Subjects were classified as: AOM with major surgery, AOM with minor surgery, or AOM with no surgery. Subject demographics, AOM – related utilization and costs, and antibiotic prescriptions were measured during the study period. RESULTS: 322,626 subjects were included in the study, with 97% falling into the AOM with no surgery category. Approximately 50% of the subjects were 6 years of age or older, while 52% of the subjects were female. The total cost of treating AOM for these subjects was $76 million. Minor and major surgery for AOM was more prevalent in children aged 6 or older than any other age group, and was associated with substantially higher costs. In 1997, the mean cost for subjects undergoing major surgery was $4,114 (std dev=3,290) compared to $142 (std dev=335) for subjects not requiring surgery. The most commonly prescribed antibiotic overall was amoxicillin, followed by sulfamethoxazole/trimethoprim; however, prescribing patterns differed across AOM categories and age groups. CONCLUSIONS: Acute Otitis Media is a prevalent condition associated with significant medical costs. USE OF PHARMACOECONOMIC AND OUTCOMES RESEARCH IN HEALTHCARE DECISION-MAKING AND PRODUCT DEVELOPMENT