Identifying patients with both COPD and asthma in a community spirometry service

<bold>Background:</bold> Identifying patients with both asthma and COPD can be challenging but is essential to ensure that appropriate treatment is initiated. This study aims to describe the population of patients with evidence of both asthma and COPD from a community spirometry diagnostic initiative. <bold>Methods:</bold> Referrals and spirometry results for patients attending a community spirometry service between 01/11/23-04/01/23 were retrospectively reviewed. Patients were identified as asthma, COPD or both. Patients with post-BDR FEV1/FVC<0.7, 200mls and 12% reversibility post-BDR and a significant smoking history were considered to have both. <bold>Results:</bold> 35% (308/869) of patients had obstructive spirometry of which 84 (27.3%) were diagnosed with COPD, 134 (43.5%) with asthma and 68 (22%) both asthma and COPD (A+C). Only 63% of COPD patients received reversibility testing and could be evaluated. In the A+C cohort, 66% had eosinophil (EC) levels ≥0.3x10⁹/L but only 18% a FENO ≥50ppb. EC levels were not significantly different between cohorts (p=0.19) and the A+C cohort demonstrated a median FENO (23, IQR=11-34) lower than asthma (40) but higher than COPD (12, both p <0.01). The A+C cohort were 49% female, white british (66%) and had a median age of 59. The mean BMI was 27.4 (SD=6.2) and MRC 3.02 (SD=1.1). MRC scores were similar to the COPD only group (2.86; p=0.99). Rates of current/ex-smoking (84.8%) were higher than asthma (54.9%, p<0.01) and comparable to COPD (98%, p=0.07). <bold>Conclusion:</bold> 22% of COPD and asthma diagnoses had features of both conditions. Early identification of concurrent disease through community spirometry with reversibility would support the correct diagnosis and management of this condition in primary care.