title: Persistent pulmonary function impairment in children and adolescents with asthma.
abstract: OBJECTIVE
  Asthma is the most common chronic pulmonary disease, characterized by bronchial inflammation. Some children with asthma have persistent pulmonary function impairment. The prevalence and etiology of this abnormality in children with asthma in developing countries remain unknown. The objective of this study was to estimate the proportion of patients with impaired pulmonary function who were unresponsive to treatment in a group of children and adolescents with asthma, and to describe the phenotypic characteristics of the sample.
  
  
  METHODS
  Using a standardized questionnaire, we selected outpatients (5-17 years of age) diagnosed with persistent asthma. These patients underwent spirometry and skin prick tests for sensitivity to common aeroallergens. Persistent pulmonary function impairment was defined as an FEV1/FVC ratio < 0.80, even after 10 days of treatment with bronchodilators and oral corticosteroids. We used the atopic index to differentiate between patients with little or no response to the skin prick test and those with a strong response (cut-off point: 4 allergens).
  
  
  RESULTS
  We included 96 patients with a mean age of 10.6 years. Of those, 52 (54.1%) were male, and 89 (92.7%) were atopic. Of the 96 patients, 8 (8.3%) had impaired pulmonary function even after the treatment. Among those patients, 8 (100%) were atopic, 7 (87.5%) had moderate or severe asthma, and 7 (87.5%) had a history of hospitalization for acute bronchiolitis.
  
  
  CONCLUSIONS
  Children and adolescents with moderate or severe asthma can present with impaired pulmonary function and be unresponsive to treatment. This clinical situation has been little studied in developing countries, and its risk factors and etiology will be better understood only through birth cohort studies.
authors.affiliation: Programa de Pós-Graduação em Pediatria e Saúde da Criança, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Luisi
authors.forename: Leonardo Araujo
authors.initials: LA
authors.lastname: Pinto
authors.forename: Laura
authors.initials: L
authors.lastname: Marostica
authors.forename: Marcus Herbert
authors.initials: MH
authors.lastname: Jones
authors.forename: Renato Tetelbom
authors.initials: RT
authors.lastname: Stein
authors.forename: Paulo Márcio
authors.initials: PM
authors.lastname: Pitrez
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000188:drug therapy / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology*; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000175:diagnosis; D008168:Lung / Q000503:physiopathology*; D008297:Male; D012129:Respiratory Function Tests; D012720:Severity of Illness Index; D017211:Treatment Failure