A brief questionnaire for screening asthma among children and adolescents in Rio de Janeiro, Brazil.

BACKGROUND Asthma is the most common chronic disease in childhood with recognition and detection still unsatisfactory. Questionnaires focusing on reported symptoms are a very promising and useful tool. OBJECTIVE To determine the diagnostic accuracy of a basic questionnaire (BQ) as a screening test for asthma in children and adolescents who sought medical assistance in a pediatric hospital in Duque de Caxias County, Rio de Janeiro State, Brazil. METHODS AND RESULTS A cross-sectional, observational, prospective study was carried out. A BQ with four questions was used to screen for asthma. The gold standard for a diagnosis of asthma was a minimum increase of 12 % in the first second of forced expiratory volume after a bronchodilatation test. Two hundred eleven patients, aged 5 to 15 years, who presented to the emergency department for various reasons were evaluated. The prevalence of asthma was 22 %. In 67 % of the families the annual income was less than USD 3600 and 60 % of support providers were illiterate or had less than 4 years of education. The test showed better performance when the answer to question 1 was considered separately: sensitivity = 74.50 % (95 %CI:60.50-84.70), specificity = 64 % (95 %CI: 56.40-71.10), positive likelihood ratio = 2.07 (95 %CI:1.59-2.70), positive predictive value = 37.20 % (95 %CI: 28.10-47.30), negative predictive value = 89.70 % (95 %CI: 82.90-94) and accuracy = 66.40 % (95 % CI: 55.80-78.30). CONCLUSIONS The BQ has high sensitivity and negative predictive values. It is easy to use and implement and is convenient for both the doctor and patient. It is useful for excluding a diagnosis of asthma in populations with a high or low prevalence of this disease, so long as there has been no wheezing in the previous 12 months.