Development of Dengue Infection Severity Score

Objectives. To develop a simple scoring system to predict dengue infection severity based on patient characteristics and routine clinical profiles. Methods. Retrospective data of children with dengue infection from 3 general hospitals in Thailand were reviewed. Dengue infection was categorized into 3 severity levels: dengue infection (DF), dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS). Coefficients of significant predictors of disease severity under ordinal regression analysis were transformed into item scores. Total scores were used to classify patients into 3 severity levels. Results. Significant clinical predictors of dengue infection severity were age >6 years, hepatomegaly, hematocrit 40%, systolic pressure <90？mmHg, white cell count >5000？/μL, and platelet ≤50000？/μL. The derived total scores, which ranged from 0 to 18, classified patients into 3 severity levels: DF (scores <2.5, , 58.1%), DHF (scores 2.5–11.5, , 35.5%), and DSS (scores >11.5, , 6.4%). The derived score correctly classified patients into their original severity levels in 60.7%. An under-estimation of 25.7% and an over-estimation of 13.5% were clinically acceptable. Conclusions. The derived dengue infection severity score classified patients into DF, DHF, or DSS, correctly into their original severity levels. Validation of the score should be reconfirmed before application of routine practice. 1. Introduction Dengue infection has become an international public health burden. Half of the world population are presently at risk of dengue infection. Approximately 50–100 million infected cases were reported annually. Among those infected, 500000 patients had severe infection and required hospital admission; most were children. Approximately 2.5% died from the infection [1]. The cost of care was as high as $US 2.1 billion per year in The United States of America [2]. No specific treatments are available except for symptomatic [3], which are effective in early detection [4]. In patients with severe infection, shock and hemorrhage usually follow [4, 5]. If not treated, death may be a consequence. Early detection or correct prognostication may avoid such severe complications [4, 6]. Clinical risks and various laboratory results were studied to explore their roles in the prediction of dengue severity. Among many of them were girls [7], children above 5 years of age [8], persistent abdominal pain [9], lethargy, cold hand and feet [10], hepatomegaly [11], abnormal bleeding [12], overweight [13], malnourished children [14], ascites [8], plural effusion [15], leucopenia (white