NEW YORK Studies show that antibiotic therapy may be little more effective than doing nothing when treating otitis media.
"There are 24.5 million visits per year for otitis media, and antibiotic costs alone are $240 million. The combination of direct and indirect costs for otitis media is $3.5 billion per year. Despite this, there is no universal agreement as to the best drug to use, nor is there international agreement as to when antibiotics are necessary," said Robert S. Baltimore, MD, at the Ninth Annual Infectious Diseases in Children Symposium held here.
"A study conducted in Holland and published in the early 1980s found that therapy didn't really matter. This study has been reevaluated lately," said Baltimore, who is professor of pediatrics, epidemiology and public health at Yale University School of Medicine in New Haven, Conn.
"In this study, 40 patients had no therapy for acute otitis media, and 36 were treated with myringotomy alone, which in Holland is a very frequent treatment for acute otitis media but has pretty much been abandoned in the United States. Forty-seven patients were given antibiotics alone, and 48 were treated with myringotomy and antibiotics combined," he explained.
No differences in otoscopic findings were found after seven to 14 days. No differences in the audiograms were found one to two months after treatment, and there was no difference in the relapse rate.
Four years later, these same authors published a much larger study of children 2 years of age and older. In this group, more than 90% resolved their disease when they were treated with just nosedrops and analgesics. No antibiotics were given unless their symptoms persisted for four days.
"So these authors recommend that initially we not treat children 2 years of age or older with antibiotics. We should treat them with analgesics and nosedrops, and only those who fail to improve in four days should then be given antibiotics," Baltimore said.
Most antibiotics are equal when it comes to treating otitis media. "We're treating a disease in which 75% of cases or more spontaneously improve," he explained.
"Data taken from real studies (Marchant and Shur, Journal of Pediatrics, 1992) showed that, in a hypothetical situation, if 253 patients were randomized into double-blind studies and if there was bacteriologic success in all, 93% would be cured. If there was bacteriologic failure in all, the clinical success rate would still be 62%. If you were dealing with otitis that was not bacterial, you would have success in 80%. So if an antibiotic is 100% effective, clinical efficacy would be 93%. If an antibiotic is only 27% effective, which we would usually consider quite ineffective, clinical efficacy would still be 71%. The conclusion is that excellent antibiotics appear less effective, and poor ones appear more effective in such trials," he added.
"For research purposes, tympanocentesis has been used, although I don't recommend using this as a routine. Tympanocentesis using an open-headed otoscope to withdraw fluid from the middle ear using negative pressure was used in an office practice by Virgil Howie in the 1960s in Alabama," said Baltimore.
Howie and his associates studied 617 patients who had more than 800 episodes of otitis media. Overall, 34% were due to pneumococcus, about 20% to Haemophilus influenzae, and in about 30% no pathogen was identified.
"Most studies since then have shown similar results. A compilation of data from 1992 showed similar percentages for Haemophilus influenzae and Streptococcus pneumoniae, but an increase in Moraxella catarrhalis. M. catarrhalis appears to have increased during the 1980s. It doesn't affect our treatment very much, because most studies show that patients with otitis due to M. catarrhalis improved spontaneously without the use of antibiotics," he explained.
In 1989, a seven-year, epidemiologic study of otitis media conducted in the greater Boston area that showed the prevalence of this disease. In children younger than 1 year of age, 62% had at least one episode of acute otitis media, and 17% had three or more episodes. In children younger than 3 years of age, 83% had at least one episode of acute otitis media, and 46% had three episodes or more.
A recent study conducted in North Carolina examined chronic or serous otitis media, which is fluid behind the tympanic membrane in the absence of signs of acute disease.
"These investigators studied a group of black children who attended nine day-care centers in the Chapel Hill area. The prevalence of bilateral effusions of the ear was very high. At 6 months to 9 months of age, it was 76%. So it's very hard to call that abnormal. In fact, in this group, effusion seems to be the normal characteristic," he said.
The percentage of children who had effusion when they were examined dropped over time. When the children were between 21 months and 24 months of age, only 24% had effusion. "Of great interest is that more than 95% had their effusion cleared by the age of 2," he added.
The prevalence of acute otitis media in this group of children was 2.13 episodes per child per year. Sixty-three percent had at least four months of otitis media with effusion.
"This particular group of investigators has previously shown a close relationship between episodes of upper respiratory infections and otitis media. Children in this age group who attend day care have been shown to have nine to 10 episodes of acute respiratory infection in the first year of life and an additional eight to nine in the second year of life. Their conclusion is that in such a population the natural history of upper respiratory infections strongly influences the prevalence of otitis media with effusion," Baltimore said at the symposium which was jointly sponsored by Montefiore Medical Center and Infectious Diseases in Children.
For more information:
- Baltimore, RS. Antibiotic treatment of otitis media. Presented at the Ninth Annual Infectious Diseases in Children Symposium. Nov. 23, 1996. New York.
The Otitis Media Guideline Panel issued recommendations for treating children between the ages of 1 and 3 years. These guidelines are for children with otitis media with effusion who are otherwise healthy:
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