Risk factors for dengue hemorrhagic fever in Taiwan, 2003-2013

Objectives: The pathogenesis of dengue hemorrhagic fever is not fully understood. The aims of this study were to examine the risk factors for developing dengue hemorrhagic fever after acquiring dengue infection and to identify the predictors of mortality after developing dengue hemorrhagic fever. Methods: All confirmed dengue and dengue hemorrhagic fever cases during 2003-2013 in Taiwan were included in this study. In this case-control study, we compared cases of dengue hemorrhagic fever with controls who were randomly selected from identified patients with dengue but without hemorrhagic fever, individually matched by month of onset and residential county in a 1:4 ratio. We tracked the outcomes of patients with dengue hemorrhagic fever, and analyzed the predictors of mortality. Multivariate logistic regression was used to analyze the data. Results: The study included 142 dengue hemorrhagic fever cases and 568 controls. Age over 60 (OR = 4.53, p <0.0001) and infection by the type 2 dengue virus (OR = 5.39, p = 0.0081) were two independent risk factors for dengue hemorrhagic fever. There were 24 deaths among the 142 dengue hemorrhagic fever cases. Age over 60 (OR = 3.21, p <0.027) and diabetes mellitus (OR = 3.08, p <0.005) were the two independent predictors of mortality. Conclusions: Knowledge about risk factors and prognostic factors will enable communities and health care professionals to better coordinate the effort to make early diagnoses, initiate treatment for dengue hemorrhagic fever, and minimize dengue-associated morbidity and mortality.