D-dimer as a marker of severe disease in imported malaria: a retrospective observational study

Background D-dimer has been evaluated to assess the severity of disease in sepsis and COVID-19 but its usefulness in the stratification of malaria severity is unknown. We aimed to assess the D-dimer level in imported malaria as a predicting marker of Plasmodium falciparum severe malaria. Methods We performed a retrospective monocentric study including all adult patients with a diagnosis of P. falciparum malaria and with a D-dimer test performed within 24 h from diagnosis. Sensitivity, specificity and accuracy of D-dimer in the diagnosis of severe malaria were estimated. The association between D-dimer levels and malaria severity was assessed by means of a logistic regression analysis adjusted for age and sex. Results 85 patients with P. falciparum malaria were included, mostly male (63.5%) and with a median age of 39 years (IQR: 32-51) and 21 (24.7%) were classified as severe malaria. Median D-dimer level was higher in patients with severe malaria when compared to the non-severe ones [10,943 μg/L Fibrinogen Equivalent Units (FEU)] [IQR: 5201–20,000) vs 2245 μg/L FEU (IQR: 919-5890); p = 0.0005), respectively]. In the multivariable logistic regression analysis, the D-dimer level resulted associated with a higher odd of severe disease [aOR per 1000 μg/L FEU more 1.14 (95% CI: 1.06-1.23)]. The estimated sensitivity and specificity with an optimal cut-off of 4864 μg/L FEU were 0.76 (95% CI: 0.53-0.92) and 0.73 (95% CI: 0.61-0.84), respectively, accounting for an overall accuracy of 0.74 (95% CI: 0.63-0.83). Conclusion We found that higher D-dimer levels were associated to malaria severity although the accuracy of D-dimer as a marker for the severity of disease was moderate.