Effect of Antibiotics for Otitis Media on Mastoiditis in Children: A Retrospective Cohort Study Using the United Kingdom General Practice Research Database

BACKGROUND. Information is needed on whether mastoiditis has increased in association with the decline in antibiotics prescribed to children by primary care physicians in the United Kingdom. OBJECTIVE. To determine time trends in mastoiditis incidence, the frequency of antecedent otitis media, and the effect of antibiotics for otitis media on the risk of mastoiditis in children. PATIENTS AND METHODS. We conducted a retrospective cohort study by using the UK General Practice Research Database. Children aged 3 months to 15 years between 1990 and 2006 were included. Risk of mastoiditis within 3 months after otitis media diagnosis and the protective effect of antibiotics were determined. RESULTS. There were 2 622 348 children within the General Practice Research Database; 854 had mastoiditis, only one third of whom (35.7%) had antecedent otitis media. Mastoiditis incidence remained stable between 1990 and 2006 (similar to 1.2 per 10 000 child-years). Risk of mastoiditis, after otitis media, was 1.8 per 10 000 episodes (139 of 792 623) after antibiotics compared with 3.8 per 10 000 (149 of 389 649) without antibiotics, and increased with age. Antibiotics halved the risk of mastoiditis. General practitioners would need to treat 4831 otitis media episodes with antibiotics to prevent 1 child from developing mastoiditis. If antibiotics were no longer prescribed for otitis media, an extra 255 cases of childhood mastoiditis would occur, but there would be 738 775 fewer antibiotic prescriptions per year in the United Kingdom. CONCLUSIONS. Most children with mastoiditis have not seen their general practitioner for otitis media. Antibiotics halve the risk of mastoiditis, but the high number of episodes needing treatment to prevent 1 case precludes the treatment of otitis media as a strategy for preventing mastoiditis. Although mastoiditis is a serious disease, most children make an uncomplicated recovery after mastoidectomy or intravenous antibiotics. Treating these additional otitis media episodes could pose a larger public health problem in terms of antibiotic resistance. Pediatrics 2009; 123: 424-430