Airway Obstruction and Bronchodilator Responsiveness in Adults With Acute Cough

Underdiagnosis of asthma and COPD is a challenge in primary care,[1] and we would very much like to diagnose these diseases at an earlier stage than we often do. Carrying out spirometry in the follow-up of patients who have consulted with an acute cough could be one way to do it. This was done in the GRACE study, and Saskia van Vugt and coworkers found bronchial obstruction or bronchodilator responsiveness to be present in one out of five adult patients without an established diagnosis of asthma of COPD who consulted a GP with acute cough. This proportion was lower than expected, and the authors did not give a clear recommendation of spirometry in the follow-up of coughing patients. This reserve was probably wise, since we do not know whether diagnosing the pulmonary abnormalities, which in most cases were mild, would be of much benefit, particularly when only one out of three patients were smoking. Sandelowsky and coworkers found undiagnosed COPD in 27 % of smokers above the age of 40, who had consulted a GP with a respiratory tract infection.[2] Although this prevalence of COPD is similar to that found in the general population of middle-aged and elderly smokers,[1;3] the authors recommended that smokers with RTI should be offered spirometry.

This can be defended, since disclosing COPD may encourage smoking cessation.[4] Such an effort should, however, only be a small part of the strategy to make patients with COPD give up smoking. In a recent population based study, it was found that patients with undiagnosed COPD are not eager to consult a doctor when catching a respiratory tract infection.[5] Actually, they consulted a GP less frequently than people with healthy lungs, although their illness tended to last longer.

van Vugt and coworkers found that abnormal lung function was found much more frequently in patients with acute cough who also had atopic disease or asthma in their family. Follow-up spirometry would be relevant when such patients get an acute cough. This could have been underlined in the conclusion of the study.

Reference List
(1) Lindberg A, Bjerg A, Ronmark E, Larsson LG, Lundback B. Prevalence and underdiagnosis of COPD by disease severity and the attributable fraction of smoking Report from the Obstructive Lung Disease in Northern Sweden Studies. Respir Med 2006; 100(2):264-272.
(2) Sandelowsky H, Stallberg B, Nager A, Hasselstrom J. The prevalence of undiagnosed chronic obstructive pulmonary disease in a primary care population with respiratory tract infections - a case finding study. BMC Fam Pract 2011; 12(1):122.
(3) Stratelis G, Jakobsson P, Molstad S, Zetterstrom O. Early detection of COPD in primary care: screening by invitation of smokers aged 40 to 55 years. Br J Gen Pract 2004; 54(500):201-206.
(4) Stratelis G, Molstad S, Jakobsson P, Zetterstrom O. The impact of repeated spirometry and smoking cessation advice on smokers with mild COPD. Scand J Prim Health Care 2006; 24(3):133-139.
(5) Melbye H, Joensen L, Risor MB, Halvorsen PA. Symptoms of respiratory tract infection and associated care-seeking in subjects with and without obstructive lung disease; The Tromso Study: Tromso 6. BMC Pulm Med 2012; 12(1):51.

Competing interests:   None declared

Practice-based research on common conditions such as acute cough are important yet rare. van Vugt et al. conducted such a study of the prevalence of spirometric obstruction and bronchodilator responsiveness in adults enrolled with acute cough illnesses of 28 days or less duration.1 They performed spirometry between 28 and 35 days later (i.e., mostly less than two months after illness onset). They reported that 193 (10%) of 1947 met ATS criteria for reversible airway obstruction and between 6% and 10%, depending on the criterion, had evidence for irreversible airway obstruction. They suggest a high likelihood that these subjects with spirometric abnormalities may have had undiagnosed asthma and/or COPD.

I want to congratulate the investigators on performing this study. Their results are consistent with the small body of previous practice- based research reporting that subgroups of patients with acute bronchitis have evidence of reactive airways during the acute illness.2 The finding that some patients with acute bronchitis have evidence for reactive airways may have direct clinical application, e.g., for bronchodilator treatment of the acute symptoms. I believe that application of these findings to management of chronic asthma will require further research. There are no guidelines for clinical management of patients whose acute bronchitis becomes chronic.3 What is clear, however, is that many more patients will have evidence of reactive airways during an acute illness than will develop chronic asthma. I would be cautious in drawing any clinical implications for management of asthma on the basis of a short- term cross sectional study encompassing less than 3 months duration.

I suggest that these results are best viewed as pilot data that raise important questions best answered prospectively: (1) Are these spirometric abnormalities indeed risk factors for the later development of asthma and/or COPD? (2) If so, to what extent, and what clinical strategies should be adopted? (3) Are environmental factors such as infections, that may be diagnosable only during the early stages, causally involved in initiating asthma?4 Practice-based research networks are probably best positioned to answer these important questions.

1. van Vugt S, Broekhuizen L, Zuithoff N, Butler C, Hood K, Coenen S, Goossens H, Little P, Almirall J, Blasi F, Chlabicz S, Davies M, Godycki-Cwirko M, Hupkova H, Kersnik J, Moore M, Schaberg T, De Sutter A, Torres A, Verheij T, Group ObotGP. Airway Obstruction and Bronchodilator Responsiveness in Adults With Acute Cough. The Annals of Family Medicine 2012; 10:523-529 2. Hahn DL. Acute asthmatic bronchitis: A new twist to an old problem. J Fam Pract 1994; 39:431-435 3. Hahn DL. Evaluation and management of acute bronchitis. In Hueston WJ (ed): 20 Common Problems in Respiratory Disorders. New York, McGraw-Hill, 2002, pp 141-153 4. Hahn DL, McDonald R. Can acute Chlamydia pneumoniae infection initiate chronic asthma? Ann Allergy Asthma Immunol 1998; 81:339-344

Competing interests:   None declared

Congratulations to the authors describing the GRACE project. First this is an important study setting, the real world of primary care practice. Second it confirms often quoted data about the high rates of unrecognized COPD in our patients who are symptomatic. The next step of course is to decide what to do with chronic cough patients. This and other data suggests that you consider those that smoke to be at high risk of COPD until you have proven otherwise with spirometry. For non-smokers and younger patients the same spirometry is good to help identify asthma. This type of article is important to identify the gaps in our care and the next step is to propose how to close those gaps. In this case asking about smoking and spirometry should be high on the list.

Competing interests:   None declared