I’m sure we’ve all had patients, perhaps smokers with childhood asthma, who present with breathlessness +/- cough and maybe odd spirometry findings? Is this COPD or asthma? As GPs, we know most patients don’t fit neatly into one diagnosis as guidelines often suggest! Thankfully, GOLD and GINA have produced guidance on asthma-COPD overlap syndrome (ACOS) (Diagnosis of Disease of Chronic Airflow Limitation: Global Initiative for Asthma, 2014), based on evidence and expert consensus.
Why is this important for GPs?
- Probably underdiagnosed (thought to have 10-20% prevalence in COPD patients; Thorax 2015, doi:10.1136/thoraxjnl-2014-206740).
- Increased risk of exacerbations (and possibly resultant lung function decline) which may be reduced by stepping up inhalers.
- Because of an asthma component, inhaled corticosteroids (ICS) are important, at a time of reduced usage in COPD.
Pathology
This is debated: is ACOS a consequence of smoking damage in asthmatics or a specific phenotype of asthma? Some features of ACOS can exist as early as childhood, with airway limitation and smaller than expected tubes on CT scanning.