Serum MMP3 and IL1-RA levels may be useful biomarkers for detecting asthma and chronic obstructive pulmonary disease overlap in patients with asthma.

"Declarations of competing interest Maho Suzukawa received Grants from AstraZeneca, GlaxoSmithKline, Kyorin, Kyowa Kirin, Daiichi Sankyo, Sanofi, and Shionogi and honoraria for lectures from AstraZeneca, Novartis Pharma, GlaxoSmithKline, and Sanofi. Nobuharu Ohshima received honoraria for lectures from AstraZeneca, Novartis Pharma, GlaxoSmithKline, and Sanofi. Yuma Fukutomi received honoraria for lectures from Thermo Fisher Diagnostics, Torii Pharmaceutical, Novartis Pharma, Kyorin, Sanofi, and Taiho Pharmaceutical. Masami Taniguchi received Grants from GlaxoSmithKline and honoraria for lectures from Novartis Pharma, GlaxoSmithKline, and Sanofi. Masahiro Akishita received Grants from Astellas Pharma, Bayer HealthCare, Chugai Pharmaceutical, Daiichi Sankyo, Eisai, Kracie Pharma, Mitsubishi-Tanabe Pharma, MSD, and Ono Pharmaceutical and honoraria for lectures from Daiichi Sankyo, MSD, Toa Eiyo, and Towa Pharmaceutical."

"Funding source None."

"This was a cross-sectional, observational study. This study used data obtained from the nationwide cohert study, NHOM-Asthma Study, a prospective asthma registry in Japan, and its protocol was approved by the ethics committee of the Institutional Review Board of the National Hospital Organization, Tokyo National Hospital (Approval No. 529). The NHOM-Asthma study, registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR; UMIN000027776), is a nationwide prospective, multicenter cohort study that investigated the characteristics and phenotypes of adult severe asthma in Japan; the full details of the study design have been published previously. Adult asthma patients (aged ≥18 years) diagnosed and treated for asthma for more than 1 year were recruited between July 2017 and September 2018 from 27 national hospitals (mainly belonging to the National Hospital Organization, NHO) across Japan and treated based on their physicians’ standard practices in a real-world clinical setting. Clinical data were obtained from the medical records of the patients, but the NHOM-Asthma study did not obtain airway reversibility test data or CT scans. They were requested to complete the Asthma Control Questionnaire 6, which is a basic questionnaire. In addition, patients filled out questionnaires about their smoking history and any diagnosis of COPD/emphysema, gastroesophageal reflux disease (GERD), sleep apnea syndrome, hypertension, diabetes, heart disease, stroke, arthritis, osteoporosis, mental disorder, sinusitis, and allergic comorbidities (including allergic rhinitis, allergic conjunctivitis, atopic dermatitis, hay fever, food allergy, drug allergy, and urticaria). In Japan, 38.8% of the population in 2019 experienced Japanese cedar pollinosis., Therefore, comorbidities of hay fever, specifically Japanese cedar/cypress/ragweed pollen allergy, and allergic rhinitis, which is caused by allergies other than pollen, were obtained separately. In addition, the frequencies of asthma exacerbation that required systemic corticosteroids and hospital admission in patients who were followed up for 1 year after recruitment were collected."