The National Asthma Education and Prevention Program (NAEPP) recommends pulmonary function testing as part of asthma evaluation. The objectives of this study were to determine the use of spirometry in patients with asthma by primary care physicians and asthma specialists, and to identify barriers to use of spirometry.

We developed, validated, and administered a mailed survey to primary care physicians and asthma specialists in the general community. We asked about the use of spirometry, access to spirometry, and barriers to spirometry use.

Of 975 eligible subjects, 672 (69%) completed the survey. Asthma specialists were more likely to have an office spirometer (78% [216/277] vs. 43% [169/395], P <0.001) than were primary care physicians, and more likely to report measuring pulmonary function in at least 75% of their patients with asthma (83% [223/270] vs. 34% [131/388], P <0.001). In logistic regression analysis, factors most strongly associated with reported spirometry use (in at least 75% of patients) among asthma specialists were owning a spirometer, disagreeing with the statement that the test requires excessive use of office resources, and agreeing that spirometry is a necessary part of the asthma evaluation. Among primary care physicians, owning a spirometer, agreeing that the data are necessary for accurate diagnosis, and believing that they were trained to perform and interpret the test were most strongly associated with reported spirometry use.

Pulmonary function testing is underutilized by physicians, with rates of utilization lowest among primary care physicians. Providing primary care physicians with better access to spirometry, through provision of a machine and appropriate training in its use and interpretation, may improve compliance with the NAEPP recommendations.