How long should a cough last?

Patients tend to underestimate how long a cough should last, leading to unnecessary and inappropriate use of antibiotics, according to a review of the evidence and a survey of patient beliefs.

Cough is the third most frequent reason for physician office visits, and yet doctors and patients don’t seem to have an understanding of the natural history of cough and the expected duration, said Dr. Mark Ebell of the department of epidemiology at the University of Georgia College of Public Health in Athens.

The National Ambulatory Medical Survey in 2007 showed that there were 27 million outpatient visits for cough that year. That constitutes 2%-3% of all family practice visits, said Dr. Ebell. Half of patients received an antibiotic for their cough, and half the time, it was a broad spectrum antibiotic.

“There are some real issues with how we manage cough,” said Dr. Ebell. Cough can indicate a condition that needs medical attention and a prescription therapy, but often, it is treated without evidence for antibiotics because the patient or doctor is uncomfortable with its duration.

Before patients ask their doctor how long a cough should last, they are likely to ask Google, he said. In conducting his own Google search, he found estimates ranging from 7 days to 14 days.

To get a sense of what patients think, Dr. Ebell and his colleagues surveyed Georgia residents by adding questions to the Georgia Poll, which is conducted twice a year by the Survey Research Center at the University of Georgia. Potential participants – aged 18 years or older – are randomly selected and contacted by phone. Almost 500 participated; 63% were women. It was an older population because the survey is conducted through landlines.

Participants were asked about their beliefs concerning antibiotics and the effectiveness of these drugs when the main symptom was a cough. They were asked how long they think it would take for the cough to get better if they were not taking any medicine, in six different scenarios: dry cough, coughing up yellow mucus or green mucus, or any of those kinds of cough with a slight fever, or no fever.

Patients with self-reported chronic lung disease or asthma were excluded from the survey.

Dr. Mark Ebell

Some respondents thought they would be better in as few as 2 days. Some thought the cough would last several months, but almost everyone thought it would take less than 2 weeks. There was not much difference between the scenarios, except when the scenario involved green phlegm.

The participants who had previously used antibiotics thought the cough would last longer, as did women, whites, and those with less education.

To determine how long a cough actually does last, Dr. Ebell conducted a literature search. After combing through several 100,000 potential studies, excluding those in sinusitis or people with a clear bacterial diagnosis, and focusing on those in community-dwelling, otherwise healthy adults with undifferentiated acute cough or bronchitis, he and his colleagues were left with 18 studies. In the end, only 5 of those 18 provided useful data.

The mean duration was 17-18 days. “So now we know how long a cough lasts,” said Dr. Ebell.

Although the cough usually improves significantly in 2 weeks, most patients think it should be over in a week. “And that’s a big driver, or may be a big driver, of antibiotic use,” he said. It may also lead to patients seeking repeat visits after 4 days, or asking for a “better” antibiotic after 8 or 9 days, which results in more prescriptions for broad spectrum antibiotics.

And the next time around, they are likely to say that the only drug that works for them is a broad spectrum antibiotic.

Dr. Ebell and his colleagues said they are exploring the clinical issue further, researching what physicians believe about cough, how messages in the media influence behavior, and whether there might be a discrepancy between the reality of an acute illness – its natural history – and perception.

Most importantly, he said he hopes to determine whether his findings can be used “to educate patients, to educate physicians, and hopefully create more realistic expectations about the duration of a cough [and] the duration of an acute illness, and thereby, hopefully reduce the demand for antibiotics.”

Dr. Ebell reported having no relevant financial conflicts.

– Alicia Ault

Posted July 2, 2013.