Objective: To determine the clinical characteristics and the predictors of hospital admission due to asthma among children and adolescents with asthma under treatment at a referral center. Methods: A retrospective cohort study comprising 151 children and adolescents with asthma, referred from the Unified Health Care System and enrolled in the Asthma and Allergic Rhinitis Control Program in the city of Feira de Santana, Brazil, followed for a period of 12 months and receiving asthma medication at no cost. The chi-square test was used in order to determine the associations between the studied variables and the occurrence of hospital admissions, whereas the Mann-Whitney test was used for the comparison between the groups of hospitalized patients and nonhospitalized patients. The level of significance was set at p < 0.05. Univariate analysis with logistic regression was performed in order to determine the predictors of hospital admission. Results: Of the 151 patients evaluated, 8 (5.2%) were hospitalized, in a total of 12 hospital admissions. In the univariate analysis, the only variable found to be a predictive factor was greater asthma severity (OR = 13.3; 95% CI: 2.55-70.1). Conclusions: The fact that, in our study sample, the principal predictor of hospital admission was greater asthma severity, calls for special attention being given to the care of these patients.

Keywords: Asthma; Hospitalization; Health services.

Objective: To determine the risk factors for ER visits due to asthma exacerbations in patients monitored at a referral center. Methods: Prospective cohort study of 253 outpatients (children and adults) with asthma who were monitored for 12 months at the Referral Center of the Program for the Control of Asthma and Allergic Rhinitis in the city of Feira de Santana, Brazil. Results: Exacerbations were common, and 36.5% of the patients sought ER treatment within the twelve-month period. The risk factors for asthma exacerbations were being over 20 years of age (OR = 1.34: (95% CI: 1.06-1.70), residing in an urban area (OR = 1.19; 95% CI: 1.06-1.33); having a low level of education (OR = 1.53: 95% CI: 1.00-2.39); having severe asthma (OR = 1.65; 95% CI: 1.24-2.18); and having chronic rhinitis (OR = 2.20; 95% CI: 1.00-4.80). Conclusions: In this cohort, having chronic rhinitis, having asthma that is more severe and having a low level of education were the main risk factors for ER visits due to asthma exacerbations. These results are similar to those reported for asthma patients who are receiving no regular treatment.

Keywords: Asthma/etiology; Health services; Program evaluation.

Objective: To evaluate quality of life according to the level of asthma control and degree of asthma severity in children and adolescents. Methods: We selected children and adolescents with asthma (7-17 years of age) from the Pediatric Pulmonology Outpatient Clinic of the State University of Campinas Hospital de Clínicas, located in the city of Campinas, Brazil. Asthma control and asthma severity were assessed by the Asthma Control Test and by the questionnaire based on the Global Initiative for Asthma, respectively. The patients also completed the Paediatric Asthma Quality of Life Questionnaire (PAQLQ), validated for use in Brazil, in order to evaluate their quality of life. Results: The mean age of the patients was 11.22 ± 2.91 years, with a median of 11.20 (7.00-17.60) years. We selected 100 patients, of whom 27, 33, and 40 were classified as having controlled asthma (CA), partially controlled asthma (PCA), and uncontrolled asthma (UA), respectively. As for asthma severity, 34, 19, and 47 were classified as having mild asthma (MiA), moderate asthma (MoA), and severe asthma (SA), respectively. The CA and the PCA groups, when compared with the NCA group, showed higher values for the overall PAQLQ score and all PAQLQ domains (activity limitation, symptoms, and emotional function; p < 0.001 for all). The MiA group showed higher scores for all of the PAQLQ components than did the MoA and SA groups. Conclusions: Quality of life appears to be directly related to asthma control and asthma severity in children and adolescents, being better when asthma is well controlled and asthma severity is lower.

Keywords: Asthma; Quality of life; Child; Adolescent.

Objective: To report demographic and clinical characteristics of patients with asthma who evolved to death, as well as to describe the conditions related to this outcome in a subgroup of patients admitted to the Program for the Control of Asthma and Rhinitis in Bahia (ProAR). Methods: A descriptive, retrospective, observational study. Data from clinical charts and death certificates of 16 patients of 930 subjects with severe asthma monitored at the ProAR Central Reference Center from December 2003 to June 2006 were reviewed. Results: Of the 930 patients participating in the program, 16 (1.72%) died. Of these, there were 10 males and 6 females, ranging in age from 39 to 74 years (median, 55 years); 12 (75%) of the patients were black. Time since diagnosis ranged from 1 to 68 years (median, 30 years). In 43.8 and 53.8%, respectively, there was a personal or family history of atopy. Ex-smokers (<10 pack-years) accounted for 37.5% of the cases. Causes of death listed on the death certificates were as follows: asthma or asthma exacerbations in 8 (50%); respiratory failure in 3 (18.75%); acute heart infarction in 2 (12.5%); hepatitis in 1 (6.25%); hypovolemic shock in 1 (6.25%); and cardiorespiratory arrest in 1 (6.25%). Of the 16 deaths, 13 (81.25%) occurred inside hospitals. Conclusion: Asphyxia and cardiovascular diseases were the most common atributed causes of mortality in this subgroup of patients with severe asthma. Hospital-based mortality, male gender, advanced age, long-term disease and fixed airflow obstruction were the aspects most frequently observed in the cases studied.

Keywords: Mortality; Rhinitis/treatment; Asthma/treatment; Cardiovascular diseases.

Objective: To determine, through home visits, the rate of compliance with environmental control measures in the homes of children with asthma. Methods: This study involved 98 asthma patients between the ages of 4 and 15. The parents of those children and adolescents received instruction in how to carry out environmental control measures and were encouraged to perform such measures continuously for a period of 90 days. Home visits, which included direct inspection of the domicile and administration of a questionnaire, were made before and after this 90-day period. In cases of noncompliance, parents were asked to explain why they did not carry out the control measures. Statistical analysis was performed using the McNemar test. Results: Overall compliance with the various items studied was 11.1%, ranging from -4.1% (for curtain control, p = 0.63) to 22.6% (for stuffed toys, p < 0.001). Passive smoking was reduced to 9.7% (p = 0.02). Among the families studied, the mean monthly income was 2.5 times the national minimum wage. When asked why they had not adopted the recommended measures, noncompliant parents gave, among others, the following explanations: "economic hardship" (60.1%); "the measures were too difficult to carry out" (6.1%); "nonparticipation of the father" (4%); and "lack of time on the part of the mother" (4%). Conclusion: Environmental control measures were carried out sporadically, possibly reflecting the influence of socioeconomic and cultural factors.

Keywords: Asthma; Allergens; Environmental exposure; Hypersensivity/prevention & control; Compliance

Objective: To investigate the level of agreement between the GINA questionnaire and the Asthma Control Test (ACT) in children and adolescents with asthma, as well as to compare the clinical, laboratory, and spirometric characteristics of patients with controlled and uncontrolled asthma as assessed by the two questionnaires. Methods: Children and adolescents with asthma had their level of asthma control cross-sectionally assessed by the GINA questionnaire and the ACT, the Childhood ACT (C-ACT) being used for the children in the sample. The participating patients also underwent spirometry, clinical assessment (for passive smoking, asthma severity, medication use, and type of inhaler device used), and laboratory measurements of vitamin D levels, blood eosinophils, and total IgE. Results: A total of 76 patients were assessed. Of those, 62% were male, and the mean age was 10 [9-12] years. In addition, 42% and 20% were classified as having uncontrolled asthma by the GINA questionnaire and the C-ACT/ACT, respectively. There was moderate agreement between the two questionnaires regarding identification of controlled and uncontrolled asthma (? = 0.505; p < 0,0001). The patients classified as having uncontrolled asthma by the GINA questionnaire had worse results in terms of daily inhaled corticosteroid dose, asthma severity, passive smoking, and spirometric parameters (FVC, FEV1, and FEF25-75%). However, there was no significant difference between patients classified as having controlled or uncontrolled asthma by the C-ACT/ACT. Conclusions: In children and adolescents with asthma, the level of agreement between the GINA questionnaire and the C-ACT/ACT appears to be moderate. The GINA questionnaire appears to have a stronger association with functional parameters, indicating better clinical assessment with less underreporting of uncontrolled asthma.

Keywords: Asthma; Pediatrics; Surveys and questionnaires; Therapeutics.

Objective: To assess the agreement among asthma control measures and functional exercise capacity in children and adolescents with uncontrolled and controlled asthma. Methods: Children and adolescents with asthma from 7-17 years old were selected, and they were attended in the "Pediatric Pulmonology Outpatient Clinic of State University of Campinas", in Brazil. All patients had asthma control level assessed by Global Initiative for Asthma questionnaire (GINAq), Asthma Control Test (ACT), spirometry and six-minute-walk-test (6MWT). Patients were classified as uncontrolled or controlled asthma in each test and agreement among measures was assessed by kappa statistics. The ROC curve was calculated for the 6MWT. The spirometric index obtained from spirometry was composed by FEV1, FEV1/FVC and FEF25-75%. Spirometry and 6MWT results were compared between uncontrolled and controlled asthma group by GINAq. Results: Of the 138 subjects included, 78 (56.5%) were male with median age of 11 (7-17) years old. GINAq detected 68.8% of patients with uncontrolled asthma. Moderate agreement (p < 0.001; k = 0.56) and high specificity (100%) was observed between GINAq and ACT. In 6MWT, the cut-off point of 82.03% of predicted distance was able to distinguish patients with controlled and uncontrolled asthma. Spirometric index presented 73.4% of sensitivity according to GINAq. The results for 6MWT in patients with uncontrolled asthma were the worst of all. Conclusion: This study highlights the importance of assessing more than one measure to differentiate asthma control level. GINAq identified more patients with uncontrolled asthma and presented moderate agreement with ACT. Spirometric index was associated with uncontrolled asthma according to GINAq. 6MWT was a suitable measure to distinguish patients with controlled and uncontrolled asthma.

Keywords: Asthma; Asthma control; Spirometry; Walk test; Children.

Objective: To compare children/adolescents with mild or moderate asthma and healthy subjects in terms of respiratory muscle strength, correlating it with spirometric variables in the former group. Methods: This was a cross-sectional study involving individuals 6-16 years of age and clinically diagnosed with mild/moderate asthma, together with a group of healthy, age- and gender-matched subjects. We determined spirometric values, as well as MIP and MEP, and we selected three reproducible measurements (variation < 10%). Results: We evaluated 75 patients with asthma and 90 controls. The mean age was 10.0 ± 2.6 years. There were no statistically significant differences between the controls and the asthma group regarding MIP (−89.7 ± 26.7 cmH2O vs. −92.2 ± 26.3 cmH2O; p = 0.541) or MEP (79.2 ± 22.9 cmH2O vs. 86.4 ± 24.0 cmH2O; p = 0.256). The groups were subdivided by age (children and adolescents: 6-12 and 13-16 years of age, respectively). Within the asthma group, there was a significant difference between the child and adolescent subgroups in terms of MEP (74.1 ± 24.1 cmH2O vs. 92.1 ± 21.9 cmH2O; p < 0.001) but not MIP (p = 0.285). Within the control group, there were significant differences between the child and adolescent subgroups in terms of MIP (−79.1 ± 17.7 cmH2O vs. −100.9 ± 28.1 cmH2O; p < 0.001) and MEP (73.9 ± 18.7 cmH2O vs. 90.9 ± 28.1cmH2O; p < 0.001). In the asthma group, spirometric variables did not correlate with MIP or MEP. Conclusions: In our sample, asthma was found to have no significant effect on respiratory muscle strength.

Background: Hypersensitivity to dust mites, mold and pet dander found in the home is common among patients with asthma. Home environmental control to reduce exposure to allergens is one of various therapeutic measures that can be taken. Objectives: To determine the prevalence of adequate home environmental control among a study population monitored by the Family Health Program and to identify any possible correlation with the exacerbation of asthma among children between the ages of 5 and 14 in the city of Camaragibe, located in the state of Pernambuco, Brazil. Method: A transversal study was carried out involving 210 mothers/guardians of children, to whom International Study of Asthma and Allergies in Children questionnaires were administered in order to characterize the exacerbation of asthma attacks. The Environment Assessment Guide of Allergic Patients was used to assess the bedrooms and living rooms in the home. Results: Among the 210 asthmatic children and adolescents evaluated in 2001, adequate home environmental control was observed in 141 (67.1%), and no correlation was observed between the degree of environmental control and fewer (< 3) asthma attacks (p = 0.39). Regarding the rooms where the asthmatic patients sleep, inappropriate furnishings were found in the homes of 93 patients (44.3%), including rag curtains in 84 cases (40.2%). Passive smoking was reported in 77 cases (36.7%). Conclusion: The level of home environmental control was satisfactory in the great majority of the residences, which may have contributed to the fact that no correlation was found between home environmental control and lower frequency of acute asthma attacks among the population studied.

Keywords: Key Words: Asthma. Environment Control. Frequency of Attacks.

Objective: To describe the frequency of popular myths about and features of asthma treatment in children and adolescents in an urban area in southern Brazil. Methods: The parents or legal guardians of public school students (8-16 years of age) completed a specific questionnaire regarding their understanding of asthma, asthma control, and treatment characteristics. The sample included parents or legal guardians of students with asthma (n = 127) and healthy controls (n = 124). Results: The study involved 251 parents or legal guardians, of whom 127 (68.5%) were the mothers and 130 (51.8%) were White. The mean age of these participants was 38.47 ± 12.07 years. Of the participants in the asthma and control groups, 37 (29.1%) and 26 (21.0%), respectively, reported being afraid of using asthma medications, whereas 61 (48%) and 56 (45.2%), respectively, believed that using a metered dose inhaler can lead to drug dependence. However, only 17 (13.4%) and 17 (13.7%) of the participants in the asthma and control groups, respectively, reported being afraid of using oral corticosteroids. In the asthma group, 55 students (43.3%) were diagnosed with uncontrolled asthma, only 41 (32.3%) had a prescription or written treatment plan, and 38 (29.9%) used asthma medications regularly. Conclusions: Popular myths about asthma treatment were common in our sample, as were uncontrolled asthma and inappropriate asthma management. Further studies in this field should be conducted in other developing countries, as should evaluations of pediatric asthma treatment programs in public health systems.

Keywords: Asthma/therapy; Asthma/prevention & control; Child health.

Objective: To analyze the prevalence of asthma and asthma symptoms in students of two distinct age brackets residing in the city of Tangará da Serra, Brazil. Methods: Cross-sectional, population-based study of the prevalence of asthma in children from 6 to 7 years of age and adolescents from 13 to 14, using the standardized International Study of Asthma and Allergies in Childhood, phase 1 questionnaire, validated for use in Brazil. Students who responded affirmatively to question 2 (presence of wheezing in the preceding 12 months) were classified as suffering from asthma. Results: The study comprised 3,362 students, of whom 1,634 (48.6%) were children and 1,728 (51.4%) were adolescents. Of the 1,634 children, 816 (49.9%) were male and 818 (50.1%) were female. Of the 1,728 adolescents, 773 (45.0%) were male and 955 (55.0%) were female. The prevalence of asthma among the children was 25.2%, whereas that among the adolescents was 15.9% (χ2 = 8.34; p = 0.00). The children presented higher prevalences of the following symptoms of asthma than did the adolescents: wheezing ever (54.3%), nocturnal dry cough (43.9%), wheezing in the preceding 12 months (25.2%), and from 1 to 3 attacks of wheezing in the preceding 12 months (19.1%). There were no differences between the two groups regarding physician-diagnosed asthma (approximately 4.5%). There were no statistical differences regarding the prevalence of asthma by gender in the two groups. Conclusions: Tangará da Serra has a high prevalence of asthma in children and adolescents, and this result is compatible with other studies carried out in Brazil and Latin America using the same methodology.

Keywords: Asthma/epidemiology; Child; Adolescent.

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.

Keywords: Asthma; Respiratory function tests; Allergy and immunology.

Objective: To evaluate the impact of the Programa de Controle da Asma e Rinite Alérgica em Feira de Santana (ProAR-FS, Program for the Control of Asthma and Allergic Rhinitis in Feira de Santana) on the frequency of hospitalizations for asthma in patients monitored at a referral center for one year. Methods: This was a historical control study involving 253 consecutive patients with asthma, ages ranging from 4 to 76 years. We compared the frequency of hospital admissions and visits to the emergency room (ER) in the 12 months prior to and after their admission to the ProAR-FS. During the program, patients received free treatment, including inhaled medications and education on asthma. Demographic and socioeconomic aspects were also assessed. Results: There was a significant reduction in the number of hospitalizations (465 vs. 21) and of visits to the ER (2,473 vs. 184) after their admission to ProAR-FS (p < 0.001 for both). Of the 253 patients who had been hospitalized and had had ER visits within the year prior to the admission to ProAR-FS, only 16 were hospitalized and 92 visited the ER during the follow-up year, representing a reduction of 94% and 64%, respectively. Conclusions: Implementing a referral center for the treatment of asthma and rhinitis in the Unified Health Care System, with the free distribution of inhaled corticosteroids and the support of an education program, is a highly effective strategy for the control of asthma.

Keywords: Hospitalization; Asthma; Rhinitis; Health services; Public health.

Objective: This study aimed to evaluate the prevalence of developmental defects of enamel (DDEs) in relation to asthma severity, symptom onset and pharmacological treatment in pediatric asthma patients. Methods: Children and adolescents (68 asthma patients and 68 controls), 5-15 years of age and residents of the city of Londrina, Brazil, were enrolled in the study. Medical and dental histories were collected through the use of a structured questionnaire. Each participant underwent a dental examination in which the examiner employed the DDE index. Results: Of the 68 asthma group subjects, 61 (89.7%) presented dental enamel defects, compared with only 26 (38.2%) of those in the control group. Using multivariate logistic regression analysis, we estimated the risk of DDEs in permanent dentition to be 11 times higher in pediatric subjects with asthma than in those without (OR = 11.88, p = 0.0001). The occurrence of dental enamel defects correlated with greater asthma severity (p = 0.0001) and earlier symptom onset (p = 0.0001). However, dental enamel defects did not correlate with the initiation of treatment (p = 0.08) or the frequency of medication use (p = 0.93). Conclusions: Pediatric patients with severe, early-onset asthma are at increased risk of dental enamel defects and therefore require priority dental care.

Keywords: Asthma/prevention & control; Bronchodilator agents; Adrenal cortex hormones/therapeutic use; Dental enamel; Amelogenesis.

Background: In recent decades, the prevalence of asthma has increased. Objectives: To determine the prevalence of asthma symptoms in children and adolescents from 2 to 14 years of age living in Porto Alegre (in the state of Rio Grande do Sul, Brazil) and to determine any potential correlations with socioeconomic profile, treatment and smoking in the home. Methods: A transversal study based on interviews of all families seeking medical attention in June of 2000. Results: The prevalence of asthma symptoms was 49.5%. In 66.8% of families, total income was less than four times the minimum wage, and in more than 50% of homes, the parents had had less than five years of schooling. In 98.5%, prophylactic asthma treatment was not used. In the 174 families studied, 38.7% of mothers and 43.7% of fathers were smokers (32.7% overall). Correlations were found between the following variables: exposure to smoking in the home and number of asthma attacks in the last year (p = 0.02; RR = 2.9; CI: 1.1 - 4.5); maternal level of education and number of attacks in the last year (p = 0.03; RR = 2.03; CI: 1.01 - 4.19); close living quarters and number of attacks in the last year among children exposed to second-hand smoke (p = 0.04; RR = 2.7; CI: 1.4 - 5.1); hospitalization and number of attacks in the last year (p = 0.004; RR = 1.46; CI: 1.15 -1.86); hospitalization and close living quarters (p = 0.03; RR = 1.47; CI: 1.15 -1.86). In children below the age of five, there was correlation between maternal smoking and number of attacks in the last year (p = 0.03; RR = 1.79; CI: 1.04 - 3.08). Conclusion: The prevalence of asthma symptoms was high. The community studied has limited socioeconomic resources, and there is therefore a lack of adequate treatment for asthma. Our results demonstrate the need for prioritized, standardized treatment programs that would give healthcare workers access to the appropriate materials and means of evaluation necessary for asthma control.

Keywords: Key words: Asthma. Prevalence. Smoking in the home. Treatment between episodes of asthma.

Introduction: In asthmatic children and adolescents a high incidence of temporary bronchospasm is perceived after physical exertion. Objective: To investigate incidence and severity of exercise-induced bronchospasm in children and adolescents with a clinical diagnosis of mild, moderate or severe asthma. Method: A descriptive, cross-sectional, not controlled study was carried out. The sample encompassed follow-up of 40 asthmatic patients of both genders, between 7 and 18 years of age who were not regularly using anti-inflammatory medication. A standardized exercise provocation test that consisted of steady running on a treadmill with a 10% inclination was administered Pulmonary function was tested with forced spirometry using six expiratory maneuvers repeated at approximately 1, 5 ,10,15, 20 and 30 minutes after the exercise. The highest of six FEV1 readings was used for analysis. The FEV1 was employed to evaluate the presence and to classify the severity of positive exercise induced bronchospasm (EIB). The asthmatic patients presented adequate clinical and spirometric conditions for testing (FEV1 at least 70 % of the predicted value). A drop of ³ 10% in relation to FEV1 before exercise was adopted as a criterion for (EIB). Results: 26 (65 %) patients developed EIB. The proportion by category was: mild asthma 44%, moderate and severe asthma 100%. There was a significant association between proportion of EIB and severity of asthma (p<0.05), and a significant difference between severity of EIB (confirmed by a recorded decrease in the 1 second forced expiratory volume) and asthma severity (p<0.05). Conclusion: The proportion and severity of EIB were clearly related to the clinical severity of asthma.

Keywords: Asthma, exercise-induced/diagnosis. Children. Adolescent. Spirometry/methods.

Objective: To determine whether simple diagnostic methods can yield relevant disease information in patients with rheumatoid arthritis (RA). Methods: Patients with RA were randomly selected for inclusion in a cross-sectional study involving clinical evaluation of pulmonary function, including pulse oximetry (determination of SpO2, at rest), chest X-ray, and spirometry. Results: A total of 246 RA patients underwent complete assessments. Half of the patients in our sample reported a history of smoking. Spirometry was abnormal in 30% of the patients; the chest X-ray was abnormal in 45%; and the SpO2 was abnormal in 13%. Normal chest X-ray, spirometry, and SpO2 were observed simultaneously in only 41% of the RA patients. A history of smoking was associated with abnormal spirometry findings, including evidence of obstructive or restrictive lung disease, and with abnormal chest X-ray findings, as well as with an interstitial pattern on the chest X-ray. Comparing the patients in whom all test results were normal (n = 101) with those in whom abnormal test results were obtained (n = 145), we found a statistically significant difference between the two groups, in terms of age and smoking status. Notably, there were signs of airway disease in nearly half of the patients with minimal or no history of tobacco smoke exposure. Conclusions: Pulmonary involvement in RA can be identified through the use of a combination of diagnostic methods that are simple, safe, and inexpensive. Our results lead us to suggest that RA patients with signs of lung involvement should be screened for lung abnormalities, even if presenting with no respiratory symptoms.

Keywords: Arthritis, rheumatoid; Lung diseases, interstitial; Spirometry; Radiography, thoracic; Airway ob-struction.

Objective: Studies characterizing asthma phenotypes have predominantly included adults or have involved children and adolescents in developed countries. Therefore, their applicability in other populations, such as those of developing countries, remains indeterminate. Our objective was to determine how low-income children and adolescents with asthma in Brazil are distributed across a cluster analysis. Methods: We included 306 children and adolescents (6-18 years of age) with a clinical diagnosis of asthma and under medical treatment for at least one year of follow-up. At enrollment, all the patients were clinically stable. For the cluster analysis, we selected 20 variables commonly measured in clinical practice and considered important in defining asthma phenotypes. Variables with high multicollinearity were excluded. A cluster analysis was applied using a two-step agglomerative test and log-likelihood distance measure. Results: Three clusters were defined for our population. Cluster 1 (n = 94) included subjects with normal pulmonary function, mild eosinophil inflammation, few exacerbations, later age at asthma onset, and mild atopy. Cluster 2 (n = 87) included those with normal pulmonary function, a moderate number of exacerbations, early age at asthma onset, more severe eosinophil inflammation, and moderate atopy. Cluster 3 (n = 108) included those with poor pulmonary function, frequent exacerbations, severe eosinophil inflammation, and severe atopy. Conclusions: Asthma was characterized by the presence of atopy, number of exacerbations, and lung function in low-income children and adolescents in Brazil. The many similarities with previous cluster analyses of phenotypes indicate that this approach shows good generalizability.

Keywords: Asthma/classification; Asthma/etiology; Child; Adolescent.