Assessment of asthma severity in adults with asthma treated by family practitioners, allergists, and pulmonologists.

OBJECTIVES

Accurate measurement of asthma severity is critical for research evaluating asthma health outcomes. There are, however, no widely accepted asthma severity measures. A severity-of-asthma score, which is based on self-reported information, was previously developed and validated in subjects recruited from pulmonary and allergy subspecialty practices. The purpose of this study was to validate the severity-of-asthma score in subjects treated by family practice physicians and to compare asthma severity in subjects treated by family practitioners (n = 150) with those seen by allergists (n = 217) and pulmonologists (n = 384).

METHODS

The study was an ongoing panel study of adults with asthma. Subjects were a random sample of board-certified family practice, allergy, and pulmonary physicians. Each physician registered patients with asthma aged 18 to 50 years. Of 869 subjects registered, 751 (86%) completed structured telephone interviews. The family practice panel was recruited approximately 3 years after the subspecialty panel.

RESULTS

In the family practice subjects, the severity-of-asthma score demonstrated internal consistency (Cronbach's alpha 0.76) and concurrent validity, correlating strongly with asthma-specific quality of life, SF-36 General Health and Physical Functioning scales, and subject-perceived asthma severity. After controlling for demographic characteristics, a 5-point score increment was associated with increased emergency department visits, urgent physician visits, and restricted activity days. The mean severity score was highest in the pulmonary group (11.8 +/- 6.3), followed by the allergy (10.3 +/- 5.3) and family practice (9.3 +/- 5.5) groups.

CONCLUSIONS

The severity-of-asthma score was a valid measure in generalist-treated subjects. Asthma severity varied significantly by physician specialty.