Clinical and laboratory features associated with dengue in central Taiwan during the 2023 outbreak

Purpose: Dengue outbreaks in previously unaffected areas expose immunologically naive aging populations. Distinguishing dengue from influenza and COVID-19 in the emergency department (ED) is challenging. We identified factors associated with dengue in the 2023 outbreak in central Taiwan.

This retrospective cohort study included adults with acute illness and suspected infection who underwent dengue testing at the ED of National Taiwan University Hospital Yunlin Branch from January 1 to December 31, 2023. Patients with confirmed dengue (positive NS1 antigen test) were compared with non-dengue patients. Variables with p < 0.01 in univariate analysis were selected for a multivariable logistic regression model after multiple imputation (m = 20). Subgroup models compared dengue with laboratory-confirmed influenza and COVID-19. Serial hemograms were summarized descriptively.

Of 872 adults, 154 had confirmed dengue. Epidemic link (adjusted odds ratio [aOR], 9.59), age (aOR, 1.03 per year), myalgia or bone pain (aOR, 2.51), and hemoglobin (aOR, 1.35 per g/dL) were positively associated with dengue. Malignancy (aOR, 0.20), URI symptoms (aOR, 0.47), WBC count (aOR, 0.79 per 1 × 10³/μL), and platelet count (aOR, 0.99 per 1 × 10³/μL) were inversely associated. Epidemic link, the absence of URI symptoms, and lower platelet count remained associated with dengue in comparisons with influenza and COVID-19. WBC and platelet counts were lowest around Days 4-7.

Among adults tested for dengue during an outbreak, epidemic link, the absence of URI symptoms, and lower platelet count were most consistently associated with dengue, including in comparisons with influenza and COVID-19. External validation is required before clinical application.