Reliability and concurrent validity of a handheld smart spirometry system (Spirokit) in Korea and Vietnam
Abstract We aimed to evaluate the test–retest reliability and concurrent validity of a smart spirometry system with real-time software guidance compared to conventional laboratory spirometers. We included adult patients with asthma and/or chronic obstructive pulmonary disease from South Korea ( n = 633) and Vietnam ( n = 452). Participants underwent spirometry using the smart device and reference spirometers. Within-device test–retest reliability was assessed by repeating smart device measurements after a 30-min interval, whereas concurrent validity was evaluated by comparing smart device measurements with those obtained using reference spirometers. In South Korea, concurrent validity showed high agreement (intraclass correlation coefficient [ICC] range: 0.922–0.973 across forced vital capacity [FVC], forced expiratory volume in 1 s, forced expiratory flow at 25%–75% of FVC, and peak expiratory flow); moreover, test–retest reliability was excellent (ICC range: 0.941–0.983). Similarly, in Vietnam, the concurrent validity was high (ICC range: 0.965–0.992), with excellent reliability (ICC range: 0.973–0.997). Across both sites, Bland–Altman analyses showed that the 95% limits of agreement for FVC and FEV 1 exceeded published method-comparison thresholds, whereas ICCs indicated high relative agreement. The smart spirometry system demonstrated high test-retest reliability and small mean between-device biases, suggesting potential utility in primary care and other settings with limited spirometry infrastructure, pending confirmation in future real-world studies.