Sunday, December 2, 2012

Live from NAPCRG: how long does a cough last?

- Kenny Lin, MD

Although American Family Physician focuses on providing readers with clinical reviews and features that synthesize evidence into guidance for practice, our medical editors wear a variety of hats. In addition to serving as Deputy Editor of Evidence-Based Medicine at AFP, Dr. Mark Ebell is also an accomplished primary care researcher. Earlier today, at the annual meeting of the North American Primary Care Research Group (NAPCRG), he presented the findings from a study that provided an original take a seemingly simple question: how long does a cough last? This study compared patient expectations with a systematic review of the medical literature.

Dr. Ebell and his colleagues surveyed a sample of patients and consulted "Dr. Google" to determine public perceptions of how long a cough from an acute upper respiratory infection is supposed to last. Although estimates varied, the most common answer was one to two weeks. His team then proceeded to review the medical literature for studies of the natural history of acute cough, using the control groups from randomized trials testing an intervention such as an antibiotic. The weighted mean duration of cough in these patients was actually 17.8 days.

Since antibiotics are prescribed for at least 50 percent of patients who visit doctors for acute cough, Dr. Ebell suggested that the substantial discrepancy between patients' expectations and the actual duration of acute cough caused by respiratory infections may be a driver of excessive antibiotic prescribing. If more patients knew that a cough could normally last for two weeks or more, perhaps fewer of them would seek medical care for self-limited illness. An article in the November 1st issue of AFP provides evidence-based guidance on appropriate antibiotic use in upper respiratory tract infections.