Quantifying the Kinetics of Hematocrit and Platelet Count in Febrile Phase to Develop a Scoring System for Predicting Dengue Shock Syndrome in Adults: A Matched-case Observational Study from a Hospital in Viet Nam

IntroductionEarly prediction of dengue shock syndrome (DSS) is crucial for effective patient triage and management. The lack of consensus regarding the precise definition of the laboratory warning sign (WS) -"an increase in hematocrit concurrent with a rapid decrease in platelet count"-has made it difficult to utilize all the WS for predicting DSS. MethodsA matched case observational study was conducted among adult dengue patients hospitalized during the first four days of illness from November 2022 to August 2023, in which each DSS case was matched with three non-DSS ones. ResultsThere were 448 patients (112 DSS and 336 non-DSS) in this study. An increase in hematocrit concurrent with a rapid decrease in platelet count was observed 1-2 days prior to the development of DSS. The cut-off value of an increase in hematocrit by [≥] 5% concurrent with a decrease in platelet count by [≥] 50% as compared with those of the previous day was found to be predictors of DSS, with a sensitivity of 60.71% and a specificity of 83.04%. A DSS scoring system developed using these two cut-off values, along with the number of clinical warning signs, can be used to predict the risk of DSS in adult patients. It achieved an area under the receiver operating characteristic curve (AUC) of 0.93, sensitivity of 86.6%, and specificity of 87.8%. The Score enables triage of patients into low-, intermediate-, and high-risk groups for appropriate monitoring and management. ConclusionsThe warning sign "an increase in hematocrit concurrent with a rapid decrease in platelet count" can be defined as "an increase in hematocrit [≥]5% concurrent with a decrease in platelet count [≥]50% compared to the previous day". The DSS score, developed from traditional warning signs, serves as a good predictor of DSS in adult patients.