Severe Dengue in Adults Admitted to Intensive Care Units on Réunion Island: Clinical Spectrum, Outcomes, and Predictors of Mortality

Background Since 2017, Réunion Island has experienced successive dengue epidemics involving the co-circulation of DENV-1 and DENV-2 serotypes, leading to an increased number of severe cases. This study aimed to describe the clinical characteristics outcomes, and predictors of in-hospital mortality among adults admitted to intensive care units (ICUs) for severe dengue. Methods We conducted a multicenter retrospective study including all adults admitted to the five ICUs of Réunion Island between January 2017 and December 2022 with laboratory-confirmed severe dengue (SD), as defined by U.S. Centers for Disease Control and Prevention criteria. Clinical, biological, and outcome data were collected from electronic records. Variables significant in univariate analysis (p < 0.05) were entered into a multivariate logistic regression model to identify independent predictors of mortality. Results Among 72.434 confirmed dengue cases, 2.817 required hospitalization and 137 SD were admitted to ICUs (1.8 per 1,000 infections). The median age was 63 years (IQR 50–70), and 62% were male. Circulatory failure occurred in 62% of cases including 14% with distributive shock and 10% with myocarditis; six patients required veno-arterial extra corporeal membrane oxygenation (VA-ECMO). Hepatic and renal failures were respectively observed in 50% and 59% of patients and neurological presentations occurred in 13 patients (9%). Co-infection were present in 33% of cases and fifty-two patients (38%) were admitted with an initial diagnosis other than dengue. Despite thrombocytopenia in 78% of cases, hemorrhagic events were uncommon. The in-hospital mortality rate was 25%. Catecholamine use (OR 4.71 [1.58–14.07], p = 0.005) and respiratory rate at admission (OR 1.10 [1.03–1.17], p = 0.004) were independent predictors of mortality. Conclusions SD on Réunion Island exhibited a wide clinical spectrum in ICUs and was associated with substantial mortality, primarily due to multiple organ failure rather than hemorrhagic complications. Co-infections were common, and comorbidities likely contributed to unfavorable outcomes. Early identification and optimal management of shock and organ dysfunction remain essential to improving survival during future dengue outbreaks.