D-dimer to fibrinogen ratio as a marker for acute cerebral venous thrombosis.

Despite D-dimer to fibrinogen ratio (DFR) being reported as a prognostic factor for cerebral venous thrombosis (CVT), we note some concerns about the misused terminology (prognostic versus predictive), potential variability in D-dimer and fibrinogen assays that may impact the reliability and utility of DFR. From the statistical aspect, its validity was not adequately ensured due to inappropriate methods (inability to address multicollinearity, confounding, and multiple comparisons) and lack of validation for unvalidated discrimination cut-offs. The prognostic value of DFR was not clinically or statistically justified, given its poor-to-acceptable discrimination. Finally, an unexpectedly positive association between venous cerebral infarction and non-severe CVT suggests possible issues in data labelling, reference value, uncontrolled confounders/biases, or overadjustment. Addressing these issues would strengthen the reliability, validity, and utility of DFR in CVT prognosis.