Assessment of asthma control in a general population of asthmatics

Asthma control is typically assessed by review of symptoms and measurement of airflow obstruction by clinic spirometry or outpatient peak flow. Recently the role of questionnaires to assess asthma control has been discussed.

To investigate the frequency of asthma control in the general population using the Asthma Control Test ([ACT], ACT is a trademark of QualityMetric, Lincoln RI) and force expiratory volume in one second (FEV1).

Subjects with self-reported physician diagnosed asthma or use of asthma prescription medications attending community or sporting events were asked to complete the five-question ACT and to perform spirometry. Subjects with an ACT score of < or = 19 and/or an FEV1 of < 80% predicted were classified as having not well controlled (NWC) asthma.

2702 subjects completed both the ACT and spirometry. ACT scores < or = 19 were recorded in 27% and FEV1 < 80% predicted was noted in 26% of subjects evaluated. ACT and/or lung function was in the NWC range for 43% of subjects; 10% of subjects had both an ACT score < or = 19 and an FEV1 < 80% and 16-17% had either an ACT score < or = 19 or a FEV1 < 80%.

A considerable portion (43%) of subjects with self-reported asthma in the general population was identified with NWC. In addition, the use of ACT and spirometry were equally effective methods to identify NWC asthma.