Comparison of dengue cases severity according to the dengue classification and to the dengue revised classification

Abstract

Introduction: two classifications stratify cases of dengue according to clinical and laboratory findings: the classification proposed in the 50s and the classification revised by the World Health Organization (WHO), which has been adopted in Brazil since January 2014. Our objective was to compare the two classification methods regarding their capability of identifying the severity of each case. Methods: Cross-sectional observational study with analysis and comparisons of dengue cases which occurred from 2011 to 2013 in a tertiary referral hospital in the city of Natal/RN, Brazil, according to the Dengue Classification and the Revised Dengue Classification. The equivalence adopted was: Classic Dengue and Dengue Hemorrhagic Fever (DHF) grade I with Dengue; DHF grade II with Dengue with warning signs and DHF III and IV with Severe Dengue. Results: 2,318 records were analyzed, with a mean age of 30.32 years ± 17.89, and a population 39% male and 61% female. Based on the designated equivalence, 428 cases were concordant, 699 were discordant (212 classified as Classic Dengue and Dengue with warning signs – mucosal bleed, 62 as Classic Dengue and Dengue with warning signs – abdominal pain) and 1,191 “without classification” (cases whose medical records did not allow classification). Conclusion: The two classifications were equivalent in clinical management when cases were severe. The old classification avoids an overestimation of mild and moderate cases by using more clinical and laboratory aspects than the new classification. Mucosal bleed, abdominal pain and vomiting did not represent signs that evolved to severity, demonstrating how the imprecise use of warning signs can overestimate the data.