Acute cough should raise asthma alarm

Around one-fifth of patients consulting their primary care physician for acute cough could have undiagnosed asthma or chronic obstructive pulmonary disease (COPD), show the results of a pan-European study.

"Identifying and providing appropriate treatment and advice to these patients is likely to improve their quality of life and reduce exacerbations," say Lidewij Broekhuizen (Julius Center for Health Sciences and Primary Care, Utrecht, the Netherlands) and colleagues.

The study was conducted at 16 centers across 12 European countries that are participating in the Genomics to Combat Resistance Against Antibiotics in Community-acquired lower respiratory tract infection in Europe (GRACE) Network of Excellence. In all, 1947 patients were included who presented to their physician with acute cough (=28 days duration) but had not previously been diagnosed with asthma or COPD.

All patients underwent spirometry before and after salbutamol 400 mg administration, within 28-35 days of inclusion in the study.

Overall, 12% of patients responded to the bronchodilator (an increase in forced expiratory volume in 1 second [FEV₁] of at least 12% or more than 200 mL) and had experienced more than one other episode of wheezing, cough, or chest tightness in the previous year.

Airway obstruction was diagnosed in 10% of patients using the Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification of an FEV₁ to forced vital capacity ratio of less than 0.7. However, it was diagnosed in fewer patients (6%) when obstruction was defined by the lower limit of normal (LLN) based on age and gender.

"Although these findings are necessary but not sufficient to diagnose COPD and asthma, patients with these findings are at higher risk of having (yet undetected) chronic obstructive lung disease and might benefit from ongoing treatment," write Broekhuizen and colleagues in the Annals of Family Medicine.

They also noted significant discordance between the two definitions of obstruction. In patients aged over 50 years, twice as many were classified as having obstruction by the GOLD criteria compared with the LLN criteria (14 vs 7%), which supports previous concerns of overdiagnosis in this age group. Conversely, in patients aged under 30 years, use of the LLN criteria led to more diagnoses.

Broekhuizen and colleagues conclude that their results confirm, "that a fixed cutoff value of 0.70 (GOLD) should be used to define obstruction with caution in the extremes of age."

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