A shorter duration of antimicrobial therapy for acute otitis media (AOM) in children is associated with higher rates of clinical failure and higher symptom scores but without any associated reduction in the rates of antimicrobial resistance or adverse events.

Alejandro Hoberman, MD , of the Children’s Hospital of Pittsburgh at the University of Pittsburgh Medical Center, and his coauthors report the results of a study in which 520 children aged 6-23 months were randomized to either 10 days of amoxicillin-clavulanate therapy, or 5 days of therapy followed by 5 days of placebo.

Overall, 16% of the children treated for 10 days with antimicrobial therapy experienced clinical failure – judged as persistence or worsening of middle ear infection – compared with 34% of those who received 5 days of antimicrobial therapy (P less than 0.001).

The children who received the full 10-day course also had lower mean symptom scores in the 6-14 days after initiation of therapy, compared with those who received 5 days of treatment (1.34 vs. 1.61; P = 0.07), while the number of children whose symptom scores decreased by 50% from baseline to the end of treatment was significantly lower in the 5-day group.

However, there were no significant differences between the two groups in the rate of nasopharyngeal colonization pathogens not susceptible to penicillin: 47% in the 10-day group, compared with 44% in the 5-day group (N Engl J Med. 2016 Dec 22;375[25]:2446-56).

Similarly, the rates of recurrence and adverse events were not significantly different between the two groups.

A shorter duration of treatment has been considered as a strategy for reducing the risk of antimicrobial resistance, but clinical trials so far have showed either modest difference favoring the standard duration of treatment, or no difference at all.

“The outcome differences we found were larger than the differences that have been reported previously, mainly because the rates of clinical failure among children who received reduced duration treatment were higher in our trial than in previous trials,” Dr. Hoberman and his associates wrote.

The researchers did note that clinical failure rates were higher among children with greater exposure to other children, and those with infection in both ears rather than a single ear.

The study was supported by the National Institute of Allergy and Infectious Diseases and the National Institutes of Health. Dr. Hoberman and Dr. Judith M. Martin declared consulting fees from Genocea Biosciences, and Dr. Hoberman declared grant support from Ricoh Innovations and holding pending patents for a reduced clavulanate concentration version of amoxicillin–clavulanate potassium, and a method and device for aiding in the diagnosis of otitis media. No other conflicts of interest were declared.