Diagnostic performance of C-reactive protein level and its role as a potential biomarker of severe dengue in adults

Objective: To determine the relationship between C-reactive protein (CRP) level and the severity of dengue and the potential use of CRP in predicting acute dengue infection. Methods: A prospective observational study was performed on dengue patients admitted to a tertiary care hospital in southern India. All patients of age above 18 years, diagnosed with dengue were included in the study. The detailed laboratory parameters pertaining to dengue were recorded. CRP levels were estimated and compared between groups i.e. severe and non-severe dengue. CRP cut-off value was detected using the receiver-operator curve. Results: Totally 98 patients with a mean age of 40 years were included. Among them, 11.2% of the patients suffered from severe dengue, 54.1% of the cases had non-severe dengue without warning signs, and 34.7% had non-severe dengue with warning signs. The median CRP was significantly higher in patients with severe dengue compared to patients with non-severe dengue (96.2 mg/dL vs. 5.3 mg/dL). Univariate logistic regression analysis showed that the odd's ratio (OR) of CRP was 1.053 (P≤0.001, 95% CI=1.029-1.078). CRP at a cutoff value of 21.6 mg/L (0.929 AUC) had excellent sensitivity (100%) and specificity (81.6%) in predicting severe dengue infection. Multivariate logistic regression analysis showed that CRP (OR=1.089, P=0.013) and ALT (OR=1.010, P=0.034) were statistically significant independent predictors of dengue severity. Conclusions: CRP level could be used as a potential biomarker to predict severity of dengue in adults.