Evaluation of the WHO classification of dengue disease severity during an epidemic in 2011 in the state of Ceará, Brazil

Abstract

In 2009, the World Health Organization (WHO) issued a new guideline that stratifies dengue-affected patients into severe (SD) and non-severe dengue (NSD) (with or without warning signs). To evaluate the new recommendations, we completed a retrospective cross-sectional study of the dengue haemorrhagic fever (DHF) cases reported during an outbreak in 2011 in northeastern Brazil. We investigated 84 suspected DHF patients, including 45 (53.6%) males and 39 (46.4%) females. The ages of the patients ranged from five-83 years and the median age was 29. According to the DHF/dengue shock syndrome classification, 53 (63.1%) patients were classified as having dengue fever and 31 (36.9%) as having DHF. According to the 2009 WHO classification, 32 (38.1%) patients were grouped as having NSD [4 (4.8%) without warning signs and 28 (33.3%) with warning signs] and 52 (61.9%) as having SD. A better performance of the revised classification in the detection of severe clinical manifestations allows for an improved detection of patients with SD and may reduce deaths. The revised classification will not only facilitate effective screening and patient management, but will also enable the collection of standardised surveillance data for future epidemiological and clinical studies.

WHO Dengue Case Classification 2009 and its usefulness in practice: an expert consensus in the Americas

“…It became clear that the improved classification of cases could help the management and treatment of cases in outbreak situations -this study was subsequently published in 2014. 23 Globally published studies In Guayaquil, Ecuador at the Hospital Luis Vernaza, a qualitative study with questionnaires and focus groups has shown that nurses and doctors preferred to use D/SD. Dengue/severe dengue is much easier to apply, practical and didactic, adjusting to the changes in the epidemiological characteristic of the disease -including older populations, including dengue in pregnancy and with comorbidities.…”

Evaluation of the World Health Organization 2009 classification of dengue severity in autopsied individuals, during the epidemics of 2011 and 2012 in Brazil

“…In the present study, of the 121 cases, 106 (87.6%) were not classified as DHF/DSS because the WHO 1997 criteria were not fulfi lled, which indicates the low sensitivity of the WHO 1997 classifi cation for the detection of severe cases (8) (15) (16) (17) (22) and emphasizes the importance of adopting the WHO 2009 classifi cation (10) . Using the WHO 2009 classifi cation, we found that all autopsied individuals in this study could be considered as having SD, suggesting that the WHO 1997 classifi cation is unable to identify severe cases, including those with a high probability of death.…”

“…The WHO 2009 classifi cation proposes that countries calculate the fatality from SD by dividing the number of deaths from SD by the population of each region, and then multiplying the obtained value by 1,000. The adoption of the WHO 2009 classifi cation should improve the comparison of dengue fatality rates among different countries because it captures severe cases (8) (15) (22) . It is believed that if this indicator is used, the fatality rates from dengue can be easily compared among different regions, considering population size and the impact of the disease in each region.…”

“…However, the term DWC has been used only in Brazil, and its use has complicated comparisons of dengue rates between Brazil and other countries (7) (8) .…”

“…Many studies across the world have shown a higher sensitivity and greater ability to include a large number of cases with the WHO 2009 classifi cation that with the WHO 1997 classifi cation (8) (10) (11) (12) (13) (14) (15) (16) (17) . However, limited evidence exists on the impact of the WHO 2009 classifi cation on the notifi cation of deaths and on the evaluation of dengue fatality indicators around the world (18) .…”