Asthma morbidity among children evaluated by asthma case detection.

OBJECTIVE: Population-based asthma detection is a potential strategy to reduce asthma morbidity in children; however, the burden of respiratory symptoms and health care use among children identified by case detection is not well known.
METHODS: Data come from a school-based asthma case detection validation study of 3539 children. Respiratory symptoms, emergency department (ED) visits, and hospitalizations were assessed by questionnaire for children whose case detection result and physician study diagnosis agreed.
RESULTS: Physician evaluation of 530 case detection results yielded 420 cases of agreement (168 children with previously diagnosed asthma, 39 with undiagnosed asthma, and 213 without asthma). Children with previously diagnosed asthma were more likely to be male (P < .0001). No differences in severity were observed in children with previously and undiagnosed asthma (P = .31). Children with undiagnosed asthma reported less frequent daytime and nighttime symptoms than children with previously diagnosed asthma but more than those without asthma (P < .0001). The proportion of children with at least 1 respiratory-related ED visit in the past year was 32%, 3%, and 3% for those with previously diagnosed, undiagnosed, and no asthma, respectively (P < .0001). The proportion with at least 1 respiratory-related hospitalization was 8%, 0%, and 0%, respectively (P < .0001). There were no differences in nonrespiratory ED visits (P = .93).
CONCLUSIONS: Despite similar physician-rated severity, children with undiagnosed asthma reported significantly less frequent respiratory symptoms and health care use than children with previously diagnosed asthma. These findings suggest that the potential health gains from case detection may be smaller than expected.