The natural history of asthma in a primary care cohort.

Background: We examined the natural history of asthma in a primary care cohort of patients 10 years after the cohort was stratified for asthma risk by responses to a questionnaire and bronchial hyperresponsiveness (BHR) testing.

Methods: Children and young adults who were born between 1967 and 1979 within 1 of 4 affiliated family practices of the Nijmegen Department of Family Medicine, The Netherlands, were asked to participate in an asthma study in 1989. Of 926 patients available, 581 (63%) agreed to participate. Their family physicians' diagnoses of upper and lower respiratory tract disease and asthma were prospectively collected during the next 10 years and were analyzed.

Results: BHR or the presence of asthma symptoms at screening did not result in a significantly disproportionate number of physician visits during the next 10 years for 4 or more upper or lower respiratory tract infections when compared with patients who did not have these findings at the beginning of the study. The presence of asthma symptoms correlated with an increased risk of an asthma diagnosis or allergic rhinitis in the group of patients who did not have asthma diagnosed at start of the study. One half of the known asthmatic patients at the onset of the study (21 of 44) had no further visits to their physicians for treatment of asthma during the next 10 years.

Conclusions: In primary care, BHR testing has limited value in predicting subsequent respiratory tract disease for patients who have asthma diagnosed by a physician. The use of symptom questionnaires can be of clinical use in predicting asthma.