Combined prognostic significance of D-dimer level and platelet count in acute ischemic stroke

Background: D-dimer level and platelet count (PC) have been reported separately as significant independent predictors of Acute Ischemic Stroke (AIS). Here, we aimed to investigate the combined prognostic value of abnormal D-dimer level and PC as defined for specific in-hospital and long-term outcomes in AIS patients. Methods: A total of 1468 patients admitted for ischemic stroke within 24 h of symptom onset from April 1, 2016 to November 31, 2019 at the Department of Neurology, the First Affiliated Hospital of Harbin Medical University were included in the final analysis. Eligible subjects were divided into four groups in terms of their levels of D-dimer and PC: DD-PC- (normal D-dimer level and normal PC), DD-PC+ (normal D-dimer level and abnormal PC), DD+PC- (higher D-dimer level and normal PC), and DD+PC+ (higher D-dimer level and abnormal PC). Logistic regression model and multinomial logit model were used to estimate the combined effect of D-dimer level and PC on in-hospital outcomes including discharge outcome and early neurological changes, and poor outcomes at 3, 6 and 12 months. Results: DD+PC+ was found to be associated with the risk of in-hospital mortality (adjusted odds ratio [OR], 6.904; 95% confidence interval [CI], 2.781-17.144) and 3-month mortality (adjusted OR, 5.455; 95% CI, 2.019-14.743) compared with DD-PC-. Combination of the two indicators significantly improved the independent predictive value for functional outcomes, including early neurological deterioration (END) (OR, 3.622; 95% CI, 1.732-7.573) with threshold of at least 4-point increase on NIHSS, discharge outcome (OR, 2.713; 95% CI, 1.421-5.177); mRS of 0-1 point (OR, 0.409; 95% CI, 0.211-0.792), mRS of 0-2 points (OR, 0.234; 95% CI, 0.118, 0.461), and higher mRS-shift (OR, 2.379; 95% CI, 1.237-4.576) at 3 months; unfavorable outcome at 3 months (OR, 4.280; 95% CI, 2.169-8.446), 6 months (OR, 3.297; 95% CI, 1.452-7.488) and 12 months (OR, 4.157; 95% CI, 1.598-10.816). While comparatively weaker statistical significance was shown in DD+PC- and no correlation was found between adverse outcomes and DD-PC+. Similarly, patients with abnormal D-dimer level and PC were less likely to reach the status of stable or improving. Conclusions: Combination of D-dimer level and PC may have more significant prognostic value on END, in hospital mortality, discharge outcome, and long-term outcomes than either index of D-dimer level or PC alone in AIS patients.