Background: Evidence of limited effectiveness and concerns about developing antibiotic resistance have led to recommendations against prescribing antibiotics for common respiratory conditions; however, antibiotics continue to be used. A major factor in this is believed to be concern about the potential for serious complications if antibiotics are withheld. Petersen and colleagues studied the impact of antibiotic use on the risk of complications from common respiratory tract infections in primary care.

The Study: Researchers gathered data from 162 British general practices from 1991 to 2001. They studied all consultations for upper respiratory infection (URI), sore throat, acute otitis media, and chest infection (excluding pneumonia). Risk of complications (i.e., mastoiditis, quinsy [peritonsillar abscess], pneumonia, or new chest infection) within one month of consultation was compared for patients who were prescribed antibiotics the day of consultation versus those who were not. Data were also gathered on patients' age, sex, and socioeconomic status.

Results: The study covered 1,081,000 episodes of URI, 1,065,088 cases of sore throat, 459,876 cases of otitis media, and 749,389 cases of chest infection. Although the risk of serious complications within one month was statistically reduced in patients treated with antibiotics, this risk was very low and the numbers needed to treat to prevent one complication of URI, sore throat, or otitis media were higher than 4,000. For chest infection, the risk of pneumonia within one month was significantly reduced by antibiotics, especially in older patients. In patients older than 65 years, the percentage diagnosed with pneumonia within one month was 1.5 percent in those treated with antibiotics, and 4.0 percent in those who were not. Adjusting for smoking and underlying chronic respiratory conditions did not influence this effect.

Conclusion: The authors conclude that antibiotics are not justified to reduce the risk of serious complications of URI, sore throat, or otitis media in primary care. Conversely, antibiotics may be justified to reduce the risk of pneumonia after chest infection, especially in older patients.

editor's note: Several aspects of this study emphasize the importance of physicians remaining astute in an increasingly algorithm-driven age. First is the importance of physical examination, especially the distinctions between bronchitis and early pneumonia. The entire study depends on the validity of diagnosis by the physician. Second is the ability to override statistical significance with clinical significance. For three of the conditions studied, the risk of complications was statistically significantly reduced by antibiotic use, but the real risk to the patient was so low that treatment was not justified. Finally, and perhaps most importantly, is our responsibility to the patient who may be the “outlier” who develops the serious complication.

Although an editorial¹ looks to genomic profiling and complex computerized algorithms to assist physicians with identifying which patients will benefit from antibiotics, old-fashioned continuity and good follow-up with patients works pretty well in the meantime. The best current investment to provide early detection and prompt intervention for URIs or complications continues to be in convincing patients and caretakers that we want to know how their symptoms change.—a.d.w.