Objective: To evaluate the prevalence of asthma attacks treated in public health facilities in the city of Juiz de Fora, Brazil from February 1, 2002 to January 31, 2003. Methods: This was a cross-sectional study involving monthly analyses performed in order to evaluate the asthma attacks treated. The variables analyzed were patient gender, age, and place of residence, as well as the profile of the visits by age bracket and by the site of the visit. In addition, we attempted to determine whether asthma attacks correlated with temperature or relative humidity. Results: A total of 25,243 patients were treated for asthma attacks, accounting for 11.1% of the total number of visits to pediatric clinics and 2.7% of the total number visits to medical clinics. The mean age of the patients was 11.6 years (median, 4 years), and 52.9% of the patients were male. The analysis of the annual distribution revealed an increase in the number of asthma attacks treated in the months of May (11.5%), June (10.8%), and July (10.9%). Asthma attack presented a strong inverse correlation with temperature (-0.86) and a weak inverse correlation with relative humidity (-0.27). Statistically significant differences, in terms of mean age and gender, were found between patients with asthma attacks treated in emergency rooms and those treated in basic health clinics. The evaluation by age bracket revealed a predominance of males among patients younger than 12 years of age and a predominance of females among those aged 12 or older. Conclusion: We found that asthma represents a significant public health problem in this city. Local strategies are urgently needed in order to increase in the availability of prophylactic treatment.

Keywords: Asthma/epidemiology; Prevalence; Public Hospitals; Brazil