Comparison between the traditional (1997) and revised (2009) WHO classifications of dengue disease: a retrospective study of 30 670 patients

Tropical Medicine & International Health
Volume 23, Issue 12  Pages: i-iv, 1281-1407  December 2018
https://onlinelibrary.wiley.com/toc/13653156/current

Original Research Papers
Comparison between the traditional (1997) and revised (2009) WHO classifications of dengue disease: a retrospective study of 30 670 patients
Natal Santos da Silva, Eduardo A. Undurraga, Alice Tobal Verro, Maurício Lacerda Nogueira
Pages: 1282-1293
First Published: 03 October 2018
Abstract
Objective
To compare WHO’s traditional (1997) and revised (2009) guidelines for dengue classification, using a large sample of patients of all ages with varying clinical conditions from a dengue‐endemic area in Brazil.
Methods
We compared 30 670 laboratory‐confirmed dengue cases (1998–2012) using both WHO’s dengue classification guidelines. Stereotype ordinal logistic regressions were used to analyse the association between patients’ demographics and signs and symptoms related to dengue infection severity, as defined in the 1997 and 2009 guidelines. We then compared the degree of agreement in dengue classification of both guidelines.
Results
Dengue signs and symptoms in patients were poorly correlated to disease severity as defined by both guidelines (Cramer’s V test <0.2). Hypotensive shock was the exception for both classifications, presenting dependence (Z = 56.42; P < 0.001, and Z = 55.24; P < 0.001) and high agreement (Cramers’s V = 1; P < 0.001, and Cramers’s V = 0.97; P < 0.001) for WHO 1997 and 2009, respectively. Last, we also found substantial agreement in disease classification between both guidelines (Kendall tau‐b = 0.79; P < 0.001), although 2009 guidelines were more sensitive in the detection of severe cases.
Conclusions
We hope our results will inform the debate about dengue classification guidelines, particularly concerning clinical value, study comparability, and ways in which future guidelines can support the clinical management of dengue. Our results suggest that caution should be taken when using WHO guidelines to assess dengue severity to improve clinical management of patients.
Open Access