Associations of Biomarkers and Body Water with Dengue Status and Length of Hospital Stay: A Single-Center Observational Study

Objectives: This study investigated the associations of biochemical and body water distribution parameters with dengue status, as well as their discriminatory ability, among hospitalized adults with febrile illnesses and evaluated whether dynamic changes in body water volumes were associated with length of hospital stay (LOS) in dengue patients. Methods: A prospective observational cohort study was conducted at a tertiary care hospital involving 186 hospitalized adults (age ≥ 18 years) with fever onset ≤ 5 days and suspected dengue. Body water parameters were assessed by bioelectrical impedance analysis (BIA) using the InBody S10 body composition analyzer at admission (T1), defervescence (T2), and discharge (T3) in dengue patients and at admission only in other febrile illness (OFI) cases. Laboratory data and LOS were retrieved from the hospital information system. Linear and logistic regression models were used to examine the associations and interactions. Discriminative performance was assessed using a receiver operating characteristic (ROC) curve analysis. Results: The proportion of dengue cases was 55.9% (n = 104). Higher levels of lymphocytes, hematocrit, hemoglobin, AST, and ALT were associated with an increased likelihood of dengue, whereas elevated WBC counts, neutrophils, platelets, CRP, sodium, chloride, and the extracellular water-to-total body water ratio (ECW/TBW) were associated with a reduced likelihood of dengue. ROC analysis indicated that WBC showed the best diagnostic performance. In dengue patients, a greater increase in ECW volume from admission to defervescence was associated with a longer LOS in males, and ratio-based body water parameters showed longitudinal variation across dengue phases. Conclusions: Several hematologic, biochemical, and BIA-derived body water parameters were associated with dengue status. Among dengue patients, dynamic ECW changes were associated with longer LOS in males, and ratio-based fluid indices were more sensitive than absolute water volumes in reflecting fluid redistribution throughout the dengue course.