The aspartate aminotransferase/platelet count ratio index as a marker of dengue virus infection: Course of illness

Background: The usefulness of laboratory tests in the decision-making process with regard to early identification of dengue virus infection has not been widely reported, particularly the aspartate aminotransferase (AST)/platelet count ratio index during a patient's days of illness. The aim of this study was to examine the pattern of the ratio index over the course of illness and identify whether it is a marker of dengue virus infection in dengue patients, as well as to assess the role of other laboratory tests. Methods: A chart review of 205 dengue patients was analyzed using available records of 845 laboratory results within different time intervals or exam dates during the course of illness. We used repeated measures mixed binary logistic regression analyses to model the dengue virus infection, defined as giving at least one positive antibody test (yes/no). Results: The high risk of dengue virus infection in dengue patients was found in the male gender (adjusted OR = 4.316, 95% CI: 1.285–14.498, P = 0.018), in patients with a high AST/platelet count ratio index (adjusted OR = 1.438, 95% CI: 1.057–1.957, P = 0.021), in patients with a low MCV level (adjusted OR = 0.815, 95% CI: 0.679–0.978, P = 0.028), and in patients with a low ALT level (adjusted OR = 0.996, 95% CI: 0.993–0.999, P = 0.010). Conclusion: Laboratory markers, in particular the AST/platelet count ratio index, can be useful for clinicians to strengthen the decision-making process in primary care settings. Furthermore, our model revealed that low MCV and low ALT are predictors of the dengue virus infection, while being a male increases the risk of dengue virus infection. More studies are needed to evaluate the impact of the AST/platelet count ratio index on the severity of dengue fever infection during the onset of symptoms and course of treatment.