An evaluation of the World Health Organization's 1997 and 2009 dengue classifications in hospitalized dengue patients in Malaysia

The latest revised version of the World Health Organization's dengue classification was released in 2009. A handful of studies have taken initiatives to evaluate the old and revised guidelines to determine early signs and symptoms of severe dengue. This retrospective study aimed to compare the classification of dengue using both the 1997 and 2009 guidelines in a selected cohort of dengue patients from Peninsular Malaysia between 2008 and 2012. Adult dengue patients were recruited from tertiary hospitals in two different states, Selangor and Kelantan, in Peninsular Malaysia. Their clinical manifestations were assessed. A total of 281 confirmed dengue patients were enrolled; the mean duration of illness at admission was five days. Of these, 88.6%, 10.7%, and 0.7% were classified according to the 1997 guidelines as having dengue fever (DF), dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS), respectively. When the WHO 2009 guidelines were applied, 17.1%, 78.3%, and 4.6% were classified as dengue without warning signs, dengue with warning signs, and severe dengue, respectively. Our data suggests that the revised WHO 2009 guidelines stratify a much larger proportion of patients into a category that requires a higher level of medical and nursing care.