Background: Asthma and asthma-COPD overlap (ACO) are heterogeneous airway
obstruction. This study aims to differentiate ACO and adult-onset asthma based on pulmonary
function tests, smoking history, and atopic status.
Method: This cross-sectional study of adult-onset asthma evaluated characteristics, such as
bronchodilator reversibility test, the skin prick test, total serum IgE, and serum IL-13 levels of
asthma patients who were current/former smokers with a smoking history of <10 packs-year and ≥10
packs-year and who also had taken FEV1 / FVC <0.7 post-bronchodilator.
Results: The data of 30 subjects were analyzed and divided into two groups (23 asthma and 7 ACO
subjects). The ACO patients were older compared to asthma patients (63.4 ± 4.7 vs. 53.7 ± 7.7, p =
0.004). A higher percentage of men was found in ACO than in asthma (85.7% vs. 21.7%, p = 0.004).
There was a difference in the cumulative number of cigarettes consumed in patients with ACO and
asthma (19.4 ± 6.4 vs. 7.2 ± 2.6, p = 0.014). The ratio of FEV1 / FVC post-bronchodilator in ACO
patients was significantly lower than in asthma patients (57.3 ± 6.9 vs. 65.5 ± 8.8, p = 0.033). There
was no difference in the duration of the disease between ACO and asthma (7.2 ± 6.1 vs. 6.1 ± 5.5, p =
Conclusion: Differences were seen in the number of cigarettes consumed and the ratio of FEV1/FVC
in ACO and adult-onset asthma patients. The cumulative number of cigarettes consumed could be a
distinguishing characteristic between ACO and asthma.