Background: The WHO guidelines were revised recently to identify patients with severe dengue (SD) early. We proceeded to determine the usefulness of the warning signs in the new WHO guidelines in predicting SD and we have also attempted to define other simple laboratory parameters that could be useful in predicting SD.
Methods: Clinical and laboratory parameters were recorded in 184 patients in 2011, with confirmed dengue viral infections, admitted to a medical ward in two tertiary care hospitals in Colombo, Sri Lanka.
Results: We found that the presence of 5 or more dengue warning signs were significantly (p=0.02) associated with the development of SD (odds ratio 5.14, 95% CI=1.312 to 20.16). The AST levels were significantly higher (p=0.0001) in patients with abdominal pain (mean 243.5, SD ± 200.7), when compared to those who did not have abdominal pain (mean 148.5, SD ± 218.6). Lymphocyte counts <1,500 cells/mm(3) were significantly (p=0.005) associated with SD (odds ratio 3.367, 95% CI 1.396 to 8.123). High AST levels were also significantly associated (p<0.0001) with SD (odds ratio 27.26, 95% CI 1.632 to 455.2). Platelet counts <20,000 cells/mm(3), were again significantly associated (p<0.001) with severe disease (odds ratio 1.632 to 455.2, 95% CI 3.089 to 14.71). The PCR was positive in 26/84 of the patients and we found that the infecting serotype was DEN-1 in all 26 patients.
Conclusions: The presence of 5 or more warning signs appears to be a predictor of SD. Lymphocyte counts <1,500 cells/mm(3), platelet counts <20,000/mm(3) and raised AST levels were associated with SD and could be used to help identify patients who are likely to develop SD.