Up to two-thirds of antibiotics prescribed for sore throats are unnecessary but doctors or demanding patients aren't necessarily at fault -- researchers blame less-than-ideal diagnostic methods, says a study published in the current edition of the journal Medical Decision Making.
In the study, researchers took throat swabs from 517 patients with sore throats who had visited their family doctors. After each visit, physicians were asked to record whether or not they had prescribed an antibiotic and the likelihood of group A streptococcal infection, or strep throat, in the patient.
Two-thirds of all antibiotic prescriptions were given to patients whose throat cultures came back later with negative results. In these cases, physicians overestimated the probability of strep throat by 33 per cent compared to an overestimation of only seven per cent when correct prescribing decisions were made (ie. the culture was positive and antibiotics were prescribed). "Family doctors can't always make a precise diagnosis with only the patient's story and clinical findings to rely on," says Dr. Warren McIsaac, associate professor of family and community medicine at U of T and family physician at Mount Sinai Hospital. "However, we currently don't have acceptable diagnostic tools that give you an immediate answer."
McIsaac says the rapid testing method widely used in the United States is quick, but results are unreliable and often warrant a throat swab anyway. The two- to three-day waiting period for results is also unacceptable for patients who want immediate relief and for doctors who feel pressured to make a decision about antibiotics. "Family doctors have made the best of a difficult situation," he says, adding that only ten to 20 per cent of sore throats test positive for strep. "Forty per cent of the population gets antibiotics at least once per year, making a seemingly trivial sore throat a great cost to society when it's played out thousands of times across the country every day."
Journal
Medical Decision Making