When antibiotics work best in AOM

Antimicrobial therapy for acute otitis media (AOM) is effective, but it’s not for everyone. A new study out of Finland shows that antibiotics are highly effective in treating AOM, but many children can also recover without them. The study authors say their research is the first to weigh which subgroups of children with AOM respond best to antibiotics.

Acute otitis media is one of the most common infections in young children, and one of the primary reasons antibiotics are used in this age group in the outpatient setting. Antibiotic use has been debated, primarily over concern about antimicrobial resistance along with evidence that some children seem to recover without antibiotic use.

"Because bacterial resistance to antimicrobial agents is a major public health problem worldwide, every effort should be made to avoid unnecessary antimicrobial treatment," the report notes. "Some unnecessary antimicrobial treatment could be avoided by identifying patients who may be less likely to require it for the management of AOM."

The study, published in Pediatrics, reviewed the efficacy of treatment with amoxicillin-clavulanate compared with a placebo over 7 days in children aged 6 to 36 months. In all, 161 children were treated with antibiotics, and 158 children were enrolled in a placebo group. The median age of children in the study was 14 months, and over half were boys and attended daycare. Many of the children who participated in the study-91.8%-had full or bulging tympanic membranes at the onset of the study; 76.5% had purulent fluid; and 9.7% had hemorrhagic redness of the tympanic membrane.

Paula Tähtinen, MD, PhD, of the Department of Pediatrics and Adolescent Medicine at Turku University Hospital in Finland and lead author of the study, says the report underscores the importance of accurate diagnosis in pediatric otic conditions. 

"Our results emphasize the importance of accurate diagnosis of AOM; children with severe bulging of the tympanic membrane seem to benefit most from antimicrobial treatment. On the other hand, children with peaked tympanogram are at low risk for treatment failure, and they may be optimal candidates for initial observation," Tähtinen says.

In the study, antimicrobial treatment was found to be very effective in the management of AOM, Tähtinen says. Children in the study received amoxicillin-clavulanic acid or placebo. The research team did not compare different antimicrobial agents, doses, or treatment durations. Based on the results, Tähtinen says antimicrobial treatment was found to be the most effective among children with severe bulging of the tympanic membrane.

"In this subgroup, 2 children need to be treated with antimicrobials to prevent treatment failure in 1 child," Tähtinen says. "All children should receive adequate pain medication regardless of whether antimicrobials are prescribed or not."

Treatment failure occurred in 31.7% of the overall study population, but advanced age (aged 24 to 35 months) along with peaked tympanograms at the onset of therapy decreased the risk of treatment failure. In children who received antimicrobial treatment, the rate of failure was 18.6%, and 44.9% in the placebo group.

"Antimicrobial treatment was superior to placebo in each prognostic factor group. However, children [aged] older than 2 years and children with peaked tympanogram were at lower risk for treatment failure, and these children could be treated with initial observation," Tähtinen says.

The research team notes that children with severe bulging of the tympanic membrane seem to benefit most from antimicrobial treatment. In that group, researchers found that 64% who received placebos experienced treatment failure compared with just 11% who received antibiotics.

"The interaction between bulging of the tympanic membrane and treatment group suggested that the effect of antimicrobial treatment varies depending on the severity of bulging," the report notes. "These results are logical because bulging of the tympanic membrane has been shown to be associated with the presence of a bacterial pathogen in the middle ear. Furthermore, bulging of the tympanic membrane was the finding judged best to differentiate AOM from otitis media with effusion by AOM experts."

Severe bulging of the tympanic membrane had no effect on treatment failure in children who received antibiotics, according to the study. Of those children with severely bulging tympanic membranes, reasons for treatment failure included worsening of the child's overall condition (53.3%); no improvement in overall condition by day 3 (23.3%); no improvement in otoscopic signs by day (13.3%); and perforation of the tympanic membrane (6.7%).

"Our subgroup analysis showed that severe bulging of the tympanic membrane almost doubled the hazard for treatment failure in children in the placebo group compared to moderate, mild, or no bulging of the tympanic membrane," the report notes.

The research team also found that children with peaked tympanogram may be better candidates for observation and more conservative management.

Tähtinen says she hopes the results of the study will be applied to daily pediatric practice, particularly when it comes to discussing treatment options with parents.

"By withholding antimicrobial treatment from children with peaked tympanograms, the use of antimicrobials and the development of antimicrobial resistance could be reduced without increasing the risks for the child," she says.