BOSTON—Although pharyngitis not caused by group A streptococci (GAS) does not require treatment, 75% of adult patients who visit their physicians because of a sore throat receive antibiotics. Yet, only about 10% of these patients actually have a GAS infection. A recent cost-effectiveness analysis compared five treatment strategies for patients with suspected pharyngitis and found that empiric therapy is not justified in the majority of cases but should be reserved only for those with a high probability of GAS infection.[1]

The investigators constructed a decision model to evaluate common treatment strategies for adults suspected of having pharyngitis. Five strategies were identified: observation only, empiric antibiotic therapy, throat culture for all patients (with antibiotics given after a positive result), optical immunoassay (OIA) followed by culture (with antibiotics given for a positive result on either test), and OIA alone for all patients (with antibiotics for a positive result). The efficacy of each strategy was examined in relation to four outcomes: acute rheumatic fever, peritonsillar abscess, duration of symptoms, and allergic reactions to treatment.

EMPIRIC THERAPY COSTLY, LESS EFFECTIVE

According to baseline assumptions, probabilities, and cost estimates, four of the five diagnostic/treatment strategies produced fairly similar results. The culture-alone strategy was the most effective (and the least expensive), followed by OIA/culture, OIA alone, and observation. Empiric therapy was less effective than the other strategies and was the second most expensive. Sensitivity analyses determined that the prevalence of GAS pharyngitis among patients with sore throats would have to be 41% for empiric therapy to more effective than the culture-alone strategy and 71% for it to be the least expensive strategy.

The strategy used by many physicians—obtaining a culture and treating empirically—had basically the same low level of effectiveness as did empiric therapy alone.

The authors noted that many patients have strong opinions about whether or not they are given an antibiotic for a sore throat and that this can affect physicians’ prescribing behavior. However, surveys have shown that patients’ satisfaction is related more to their perception of the physician understanding their concerns than to a prescription for antibiotics.

—Gale Jurasek