A new symptom-based questionnaire for predicting the presence of asthma.

BACKGROUND Early diagnosis and treatment of asthma is important for improving health and minimizing the social and economic burden of the disease. A simple questionnaire would provide a convenient and timesaving tool to help physicians diagnose asthma. OBJECTIVE The senior author developed a simple, pre-interview screening questionnaire--the Asthma Screening Questionnaire (ASQ)--consisting of 6 questions. The present report provides performance evidence that the ASQ is a reliable instrument for diagnosing asthma in adults. METHODS Participants were asthmatics or controls, aged 18 to 65 years. All participants completed the questionnaire (self-administered and physician-administered), and underwent spirometry and a methacholine challenge test (if there was no reversibility during initial spirometry). Sensitivity, specificity, and positive and negative predictive values were calculated for each question, and the total scores of asthmatics were compared with those of controls. The degree of agreement between the self-administered and the physician-administered questionnaire was calculated. RESULTS The main symptoms discriminating asthmatics from controls were cough more than average (88% vs 0%), cough from chest (72% vs 0%), shortness of breath with exercise (84% vs 16%), and chest tightness when lying down (72% vs 4%). A cutoff point of total score > or = 4 was associated with the highest combination of sensitivity (96%) and specificity (100%). Substantial agreement was observed between the self-administered and the physician-administered questionnaire (kappa statistic, 0.56-1.00; P<.0001). CONCLUSIONS The ASQ is a simple, inexpensive, and efficient pre-interview screening tool to diagnose asthma.