The importance of office spirometry in guiding the management of patients with chronic airway disorders in primary care

Office spirometry is used for the diagnosis of patients with asthma or chronic obstructive pulmonary disease (COPD). The study aimed to determine the outcomes of post-office spirometry of patients in primary care on their clinical diagnosis, medication treatment and referral for pulmonologist evaluation. This retrospective study was conducted in Singapore primary care clinics over two years. Demographic, clinical and prescription data were extracted from the institution electronic medical records of Asian patients 3-month before and 6-month post-spirometry. Spirometry outcomes were: Significant Bronchodilator Responsiveness (SBR); Post Bronchodilator Obstruction (PBO); SBR and PBO; and unconfirmed diagnosis. Spirometry outcomes of 343 patients were analysed. Among 151 (44.0%) with an initial diagnosis of asthma, 19 (12.6%) had SBR, which confirmed the asthma diagnosis, 9.3% had both SBR and PBO. Among 45 (13.1%) with an initial diagnosis of COPD, 10 (22.2%) had PBO which confirmed the COPD diagnosis, and 4.4% of patients had both SBR and PBO. 85 patients (24.8%) were referred to pulmonologist for further evaluation, with the highest referral rate observed in patients with SBR + PBO (33.3%). Spirometry is essential to affirm diagnosis of patients with COPD in primary care. Majority of patients with an asthma diagnosis did not demonstrate positive SBR, and further evaluations might be required. Spirometry should be scaled to ensure that patients receive the appropriate treatment.