The use of objective measures of asthma severity in primary care: a report from ASPN

The rising incidence of and mortality from asthma have prompted the development of practice guidelines for diagnosis and management. A cornerstone of these guidelines is the use of objective measures of asthma severity: spirometry or peak expiratory flow rates. We studied the extent to which primary care clinicians used objective measures of asthma severity.

Practices affiliated with the Ambulatory Sentinel Practice Network in the United States and Canada collected data on 490 asthma-related encounters involving 439 patients. For each encounter, the practice recorded the availability of the results of spirometry, peak expiratory flow rates, oxygenation (arterial blood gas or pulse oximetry), and chest radiograph to the clinician.

Objective data about asthma severity were infrequently available to ASPN clinicians at the time of the encounter. In 67.8% of encounters, there was no current or past spirometry result, in 55.1% there was no current or past peak flow measurement, and in 74.3% there was no current or past determination of oxygenation. Chest radiographs, on the other hand, were available for most (64.7%) patients. The lack of objective measures was not related to lack of access to the relevant technologies. Most practices noted easy access to spirometry (72.2% of practices), peak flow meters (72.2%), oxygenation determination (61.1%), and radiography (83.3%).

In this study, most primary care clinicians did not have objective data about the severity of their patients' asthma at the time of the encounter. This relative lack of objective data was not explained by lack of access to the relevant technology for determining severity. It may instead reflect the opinion of primary care physicians that such information is not necessary in the care of these patients.