Differences between asthma-COPD overlap syndrome and adult-onset asthma

Eur Respir J. 2017 May 1;49(5):1602383. doi: 10.1183/13993003.02383-2016. Print 2017 May.


Differences between asthma-COPD overlap syndrome (ACOS) and adult-onset asthma are poorly understood. This study aimed to evaluate these differences in a clinical cohort of patients with adult-onset asthma, as a part of the Seinäjoki Adult Asthma Study (SAAS).188 patients were diagnosed with adult-onset asthma and re-evaluated 12 years after diagnosis. They were divided into three groups based on smoking history and post bronchodilator spirometry values: 1) never- and ex-smokers with <10 smoked pack-years; 2) non-obstructive (forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ≥0.7) patients with ≥10 pack-years; and 3) ACOS patients with ≥10 pack-years and FEV1/FVC <0.7.ACOS patients had lower diffusing capacity (DLCO/VA 86% predicted versus 98 or 96% predicted; p<0.001), higher blood neutrophil levels (4.50 versus 3.60 or 3.85×109 L-1; p=0.008), and higher IL-6 levels (2.88 versus 1.52 or 2.10 pg·mL-1, p<0.001) as compared to never- and ex-smokers with <10 pack-years, or non-obstructive patients with ≥10 pack-years smoking history, respectively. ACOS patients also showed reduced lung function, higher remaining bronchial reversibility and a higher number of comorbidities.This study shows distinct differences in diffusing capacity, blood neutrophil and IL-6 levels, bronchial reversibility, lung function and comorbidities between ACOS and adult-onset asthma. The present findings should be considered in the comprehensive assessment of adult asthma patients.

Trial registration: ClinicalTrials.gov NCT02733016.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Age of Onset
  • Asthma / complications*
  • Asthma / diagnosis*
  • Biomarkers / blood
  • Comorbidity
  • Female
  • Finland
  • Follow-Up Studies
  • Forced Expiratory Volume
  • Humans
  • Interleukin-6 / blood
  • Leukocyte Count
  • Male
  • Middle Aged
  • Neutrophils / cytology
  • Pulmonary Disease, Chronic Obstructive / complications*
  • Pulmonary Disease, Chronic Obstructive / diagnosis*
  • Smoking / epidemiology*
  • Spirometry
  • Syndrome
  • Vital Capacity


  • Biomarkers
  • IL6 protein, human
  • Interleukin-6

Associated data

  • ClinicalTrials.gov/NCT02733016