Anna Jetske Baron,1– 3 Bertine MJ Flokstra-de Blok,1,2,4 Ellen van Heijst,2,5 Roland A Riemersma,6 Agnes MM Sonnenschein-van der Voort,7 Esther I Metting,2,6 Janwillem WH Kocks1,2,8 1General Practitioners Research Institute, Groningen, the Netherlands; 2University of Groningen, University Medical Center Groningen, GRIAC Research Institute, Groningen, the Netherlands; 3Department of Pulmonary Diseases and Tuberculosis, University Medical Center Groningen, Groningen, the Netherlands; 4Department of Pediatric Pulmonology and Pediatric Allergology, University of Groningen, University Medical Center Groningen, Beatrix Children’s Hospital, Groningen, the Netherlands; 5Astma/COPD Dienst, CERTE Laboratories, Groningen, the Netherlands; 6Department of General Practice and Elderly Care Medicine, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands; 7GlaxoSmithKline, Zeist, the Netherlands; 8Observational and Pragmatic Research Institute, SingaporeCorrespondence: Anna Jetske Baron Email annajetske@gpri.nlPurpose: Primary care COPD guidelines indicate that COPD patients with asthma characteristics should be treated as having asthma. This study aims to describe the prevalence of asthma characteristics in patients with a pulmonologist-confirmed working diagnosis of COPD or ACO.Patients and Methods: This retrospective cross-sectional study used real-life data (collected between 2007 and 2017) from a Dutch asthma/COPD-service, a structured web-based system in which pulmonologists support general practitioners in their diagnosis of patients with suspicion of obstructive lung disease. The prevalence of asthma characteristics (history of asthma, atopy, symptoms, and reversibility) and blood eosinophil (Eos) counts were assessed in patients with a working diagnosis of COPD or ACO.Results: Of the 14,141 patients, ≥ 40 years in the dataset, 4475 (31.6%) were diagnosed with asthma, 3532 (25.0%) with COPD, and 1276 (9.0%) with ACO. Asthma characteristics were present in 65.6% (n=1956) of the COPD and ...