Severe dengue in hospitalized adults at two tertiary referral hospitals in northern Vietnam: clinical features and outcomes

BACKGROUND: Dengue remains a major global health concern; while most infections are self-limiting, a subset progresses to severe disease with substantial mortality. Updated data on severe dengue in hospitalized adults, particularly those managed in tertiary referral settings, remain limited. This study aimed to characterize the clinical features, laboratory abnormalities, and outcomes of adults with WHO-defined severe dengue admitted to two tertiary referral hospitals in northern Vietnam. METHODS: We conducted a prospective observational cohort study of adults with WHO-defined severe dengue admitted to two tertiary referral hospitals in northern Vietnam between 2020 and 2024. Demographic, clinical, laboratory, and outcome data were systematically collected, and survivors were compared with non-survivors to identify factors associated with mortality. RESULTS: A total of 104 adults with severe dengue were enrolled, of whom 31 (30%) died. Non-survivors were significantly older than survivors (median age 62 vs 45 years) and more frequently had hypertension (48% vs 23%; p = 0.011) and diabetes mellitus (45% vs 11%; p < 0.001). Shock occurred in 81% of non-survivors compared with 15% of survivors (p < 0.001). Fatal cases showed more frequent multi-organ failure and metabolic derangements, including acidosis with hyperlactatemia, renal dysfunction, hyperammonemia, coagulopathy, hypoalbuminemia, and elevated cardiac troponin I. In multivariable Firth logistic regression, shock (adjusted odds ratio [aOR] 8.59, 95% CI 2.38-36.27; p < 0.001) and cumulative organ dysfunction burden (aOR 2.69 per additional organ/system, 95% CI 1.57-5.36; p < 0.001) were independently associated with in-hospital mortality. Organ dysfunction burden also stratified time-to-event outcomes (log-rank p < 0.001). CONCLUSIONS: In this tertiary referral cohort of adults with WHO-defined severe dengue in northern Vietnam, mortality was high and was mainly associated with older age, comorbidities, shock, metabolic failure, and multi-organ dysfunction; shock plus cumulative organ dysfunction provided a practical risk-stratification signal.