Although the cause is unclear, spirometry measurements obtained at home had poor agreement with results obtained in the clinic, according to findings presented at the American Thoracic Society (ATS) International Conference held virtually from May 14 to 19, 2021.

Researchers obtained home and clinic spirometry data from the CAPTAIN study ( Identifier: NCT02924688), a phase 3A, double-blind parallel-group study in adults with uncontrolled asthma despite pharmacologic therapy. Patients had spirometry measurements taken at least once in the clinic using a MasterScope device, and recorded measurements at home each day using a peak flow meter (AM3 device).

Among the 2434 patients who had both clinic and home spirometry measurements available, the agreement between clinic and home trough forced expiratory volume in 1 second (FEV1) measurements was poor. At baseline, the lower and upper limits of agreement were -812 mL and 943 mL, respectively, and at week 24, these values were -771 mL and 980 mL, respectively.  A total of 6% of patients were outside of the limits of agreement at baseline and week 24.

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According to the researchers, possible explanations for the lack of agreement included the different devices and methodologies as well as a lack of supervision and coaching for home measurements.

“The comparison of home and clinic spirometry in the CAPTAIN study suggests that home spirometry performed with the AM3 device cannot be used as an alternative to clinic spirometry, and that caution should be exercised when using home spirometry data in research or clinical care,” the study authors concluded.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.


Gardiner F, Pizzichini E, Bailes Z, et al. A comparison of clinic versus home spirometry in the CAPTAIN study. Presented at: the American Thoracic Society (ATS) 2021 International Conference; May 14-19, 2021. Abstract A1348

This article originally appeared on Pulmonology Advisor