Mortality indicators among chronic Chagas patients living in an endemic area

Abstract

Background Chagas disease is a serious social–medical problem in Latin American countries because of its high incidence, morbidity and mortality. Our aim was to identify, from demographic, personal history, clinical and electrocardiographic variables, those that might have independent prognostic value regarding mortality, among a population of chronic Chagas patients from a single endemic area where vector transmission has been halted. Methods and results Over a mean of 18.5 years, we followed up a prospective cohort of 120 individuals with chronic Chagas disease. Twenty dichotomous variables with prognostic potential for chronic Chagas disease patients were initially evaluated using the Cox model (univariable analysis), to calculate the proportional mortality risk from all causes, cardiovascular causes and sudden death, relative to each variable separately. Of these, 12 variables presenting statistical significance ( p < 0.05) were included in a multivariable model to determine which of them would have independent prognostic value regarding mortality. Over the follow-up, there were 42 deaths. Eight variables were proven to be independent prognostic factors for mortality, in relation to the three types of death analysed: age ≥ 39 years, black skin colour, high-degree right-branch block, anterosuperior division block of the left branch, high-degree right-branch block associated with anterosuperior division block of the left branch, high-degree left-branch block, polymorphic ventricular extrasystoles and PR interval ≥ 0.16 s. Conclusions The presence on conventional electrocardiograms of polymorphic ventricular extrasystoles or high-degree left-branch block, among a population of chronic Chagas patients, constitutes the most important independent factor for poor prognosis.