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.