How long does a cough last? (longer than you'd think)

At December's annual meeting of the North American Primary Care Research Group (NAPCRG), fellow American Family Physician editor Mark Ebell, MD, MS 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's team 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. (As one of my colleagues observed with a smile after hearing about Dr. Ebell's presentation, "Cough from acute bronchitis is expected to last for 2 weeks. With antibiotics, it only lasts 14 days.")

Update (1/15/13): this research study was just published in the January/February issue of Annals of Family Medicine.

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A slightly different version of the above post first appeared in the AFP Community Blog.