Spirometry Utilization Among Patients with Asthma

To examine predictors of spirometry use at a tertiary academic health system and association between receipt of spirometry and outcomes.

We conducted a retrospective cohort study of adult patients with an ICD-9 CM diagnostic code for asthma and a 2014 outpatient visit in either a community health center or private practice associated with a tertiary academic medical center. The main outcome was receipt of spirometry during a 2007-2015 "exposure period." We secondarily examined future hospitalizations and emergency department (ED) visits during a follow-up period (2016-2019).

In a sample of 394 patients, the majority were white (48%; n=188) and female (72%; n=284). Mean (SD) age was 52 years. Approximately half (185, 47%) of the patients received spirometry and 25% (n=97) saw a specialist during the exposure period. Nearly, 88% (n=85) of patients who saw a specialist received spirometry. More than half of the cohort (220/394, 56%) had an ED visit or admission during the follow-up period. Of these, 168 (76.4%) had not seen a specialist and 111 (50.5%) had not received spirometry within the exposure period. We saw no association between spirometry in the exposure window and future ED visit or hospitalization.

In a cohort of patients at a tertiary medical center, spirometry was underused. We observed a strong association between seeing a specialist and use of spirometry, suggesting a need to better incorporate spirometry into routine primary care for patients with asthma. Among 220 patients who had an asthma-related hospitalization or ED visit in 2016-2019, the majority had no record of receiving spirometry and no documentation indicating a prior specialist visit.