Diagnosing asthma-COPD overlap syndrome in primary care

Access to the full content of this site is available only to registered healthcare professionals. Register to read more
  • Prevalence of asthma-COPD overlap syndrome (ACOS) was high in newly-diagnosed patients with COPD. 
  • Different diagnostic criteria produced wide variation in proportion of patients with ACOS.

Why this matters

  • First study to apply different ACOS definitions in the same cohort.

Key results

  • ACOS prevalence was 6.8% overall and 37.8% in newly-diagnosed patients with COPD. 
  • Compared to COPD-only patients, patients with ACOS were younger, had more dyspnea, lower FEV1 and FEV1:FVC, but no difference in pack-years.
  • Patients with ACOS and wheeze (ACOS-W) had more dyspnea than those without wheeze (P<.0001). 
  • Patients with ACOS-W were younger (P=.02), had higher BMI (P<.01), lower post-bronchodilator (BD) FEV1:FVC (P=.02), and lower post-BD FEV1% predicted (P<.0001), but no significant difference in pack-years and post-BD FEV1 increase. 
  • Patients with ACOS-BD reversibility (BDR) had lower FEV1:FVC (P=.03), but no significant difference in age, BMI, pack-years or FEV1% predicted. 
  • Patients with ACOS-W+BDR had more dyspnea than patients with ACOS-W- and ACOS-BDR-only (P<.01 for both), but no differences in age, pack-years, FEV1% predicted or FEV1:FVC.

Study design

  • Primary care screening of 3875 patients aged ≥35 y, with tobacco exposure, ≥1 respiratory symptom, and no previous COPD diagnosis. 
  • Funding: Boehringer-Ingelheim and Pfizer.


  • No gold-standard diagnostic criteria for ACOS. 
  • Danish-only population.