How Long Does a Cough From Respiratory Illness Last?

Cough from respiratory illness is one of the most common reasons that patients seek care in both the outpatient primary care setting and the emergency department (ED). Cough due to respiratory illness is a self-limited condition in the majority of cases, but patients still seek care at clinics and EDs seeking relief or their symptoms. Maybe the reason for this is patients’ expectations of duration of cough and the actual natural history of cough from respiratory illness are mismatched. So how long does a cough from respiratory illness last?

How Long Does a Cough Last? Comparing Patients’ Expectations With Data From a Systematic Review of the Literature [1]

What did they do:

• Compared:
  1. A population-based random digit dialing survey of 493 adults in Georgia to determine their expectations regarding the duration of cough from respiratory illness
  2. A systematic review of observational studies and randomized clinical trials of adults to determine the duration of cough from respiratory illness

Studies included in the systematic review:

Mean Days of Any Cough

Mean Days of Productive Cough

Results:

• 19 studies reviewed for systematic review
• Mean duration of ANY cough in published literature was 17.8 days (Range: 15.3 – 28.6 days)
• Mean duration of PRODUCTIVE cough in published literature was 13.9 days (Range: 13.3 – 17.4 days)
• Survey respondents reported that their expected duration of cough from respiratory illness should be no longer than 6.5 – 9.3 days

Limitations:

• Only a 43.6% response to survey questionnaire is a relatively low response rate
• The population-based survey is limited to adults in the state of Georgia and may not reflect beliefs or expectations regarding cough duration and antibiotic use in other parts of the US
• The systematic review had 8 studies from Europe, 7 in the US, 3 in Russia, and 1 in Kenya. Most of these studies are in countries in temperate climates and may not apply to tropical countries

Study Conclusion: There is a mismatch between patients’ expectations regarding the duration of ACI and the actual duration of cough from respiratory illness.

There was also a systematic review done reviewing the same question in the pediatric population [2]. 23 trials and 25 observational studies were included in this review and of these studies 6 of them (700 patients) looked at the duration of cough in respiratory illness. Pooling of these 6 trials showed that cough was resolved in 50% of children by day 10, and resolved in 90% of children by day 25.

Clinical Take Home Message:

It is important to emphasize the natural history of cough from respiratory illness with patients when they seek care for an episode of acute cough from respiratory illness, but it is also important to emphasize that they should seek care if they are having worsening symptoms or have alarm symptoms (i.e. High fever, bloody or rusty sputum, and/or worsening shortness of breath). In other words, it is completely normal and expected to have a cough for 2 or even 3 weeks after onset of illness!!!

References:

1. Ebell MH et al. How Long Does a Cough Last? Comparing Patients’ Expectations with Data fro a Systematic Review of the Literature. Ann Fam Med 2013. PMID: 23319500
2. Thompson M et al. Duration fo Symptoms of Respiratory Tract Infections in Children: Systematic Review. BMJ 2013. PMID: 24335668
3. Williamson HA. A Randomized, controlled Trial of Doxycycline in the Treatment of Acute Bronchitis. J Fam Pract 1984. PMID: 6384419
4. Scherl ER et al. Doxycycline in Acute Bronchitis: A Randomized Double-Blind trial. J Ky Med Assoc 1987. PMID: 3668366
5. Little P et al. Information Leaflet and Antibiotic Prescribing Strategies for Acute Lower Respiratory Tract Infection: A Randomized Controlled Trial. JAMA 2005. PMID: 15972565
6. Nduba VN et al. Placebo Found Equivalent to Amoxicillin for Treatment of Acute bronchitis in Nairobi, Kenya: A Triple Blind, Randomised Equivalence Trial. Thorax 2008. PMID: 18559367
7. Butler CC et al. Treatment of Acute cough/Lower Respiratory Tract Infection by Antibiotic Class and Associated Outcomes: A 13 European country Observational Study in Primary Care. J Antimicrob Chemother 2010. PMID: 20852271
8. Verheij TJ et al. Effects of Doxycycline in Patients with Acute Cough and Purulent Sputum: A Double Blind Placebo Controlled Trial. Br J Gen Pract 1994. PMID: 8790652

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