Mortality of Chagas' disease in Brazil: spatial patterns and definition of high-risk areas.

ABSTRACT

OBJECTIVE: To describe patterns of spatial distribution of mortality associated with Chagas' disease in Brazil. METHODS: Nationwide study of all deaths in Brazil from 1999 to 2007, where Chagas' disease was recorded as a cause of death. Data were obtained from the national Mortality Information System of the Ministry of Health. We calculated the mean mortality rate for each municipality of residence in three-year intervals and the entire period. Empirical Bayes smoothing was used to minimise random variation in mortality rates because of the population size in the municipalities. To evaluate the existence of spatial autocorrelation, global and local Moran's I indices were used. RESULTS: The nationwide mean mortality rate associated with Chagas' disease was 3.37/100 000 inhabitants/year, with a maximum of 138.06/100 000 in one municipality. Independently from the statistical approach, spatial analysis identified a large cluster of high risk for mortality by Chagas' disease, involving nine states in the Central region of Brazil. CONCLUSION: This study defined geographical priority areas for the management of Chagas' disease and consequently reducing disease-associated mortality in Brazil. Different spatial-analytical approaches can be integrated to provide data for planning, monitoring and evaluating specific intervention measures.