Analyses of clinical and laboratory characteristics of dengue adults at their hospital presentations based on the World Health Organization clinical-phase framework: Emphasizing risk of severe dengue in the elderly

Background/Purpose: Dengue clinically dynamically changes over time; the World Health Organization (WHO) dengue classification framework proposed 3 dengue clinical phases—febrile (days 1–3), critical (days 4–6) and recovery (days ≥7) phases. This study aimed to better understand clinical and laboratory characteristics in adults (≥18 years) suffering dengue in different clinical phases at their hospital presentations. Methods: A retrospective analysis of adults suffering dengue between 2008 and 2014. Results: Of the 669 included dengue adults, 146 (21.8%) were elderly (≥65 years), and 27 (4%) suffered severe dengue. When compared with those in febrile phase, significantly higher incidence of ascites, mucosal bleeding, and/or gastrointestinal bleeding; lower white blood cell (WBC) and platelet counts; higher hematocrit, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) values were found in critical phase. When compared with their younger counterparts, elderly at febrile phase had significantly lower frequencies of bone pain, myalgia, headache and rash; higher frequencies of vomiting, pleural effusion and mucosal bleeding; higher WBC count, AST and ALT levels, and lower platelet count; in critical phase, elderly had significantly higher frequencies of pleural effusion, mucosal bleeding and gum bleeding. Four (0.6%) patients experienced severe dengue in recovery phase. Significantly higher proportions of elderly developed severe dengue in both febrile and critical phases as compared with younger adults. Conclusions: Elderly had lower frequency of classical dengue symptoms, yet were at higher risk of development of severe dengue during their early dengue course. A small number of patients developed severe dengue at the WHO-proposed recovery phase. Keywords: Adults, Clinical phase, Dengue, Elderly, Severe dengue, WH