Impact of Blood Groups on Clinical Outcomes in Patients with Von Willebrand Disease

INTRODUCTION

Von Willebrand Disease (vWD) is the most common hereditary hemorrhagic disorder with diverse clinical and genetic characteristics. Transmitted as an autosomal dominant trait (except Type III), it is caused primarily by the quantitative or qualitative deficiency of von Willebrand factor (vWF). ABO blood group types can affect the pathology, severity and hence the presentation of this clinically heterogeneous entity as the genes responsible for ABO blood groups also affects vWF levels in the plasma. We conducted a study to analyze and compare different clinico-demographic aspects among O and non-O blood group patients with Von Willebrand Disease. Our primary aim was to determine the relationship of different blood groups with venous thromboembolism (VTE) in patient with vWD. Our secondary aim was to determine the association of blood groups with different comorbid conditions such as coronary artery disease, cerebrovascular disease, peripheral vascular disease, chronic liver disease, chronic kidney disease etc. in patients with vWD.

METHODS

A retrospective review was carried out to include all patients diagnosed with Von Willebrand Disease from year 2002 to 2012. Patient population was obtained by using International Classification of Diseases, 9^th revision (ICD9) codes. Data was collected with the help of electronic medical records. Multiple clinical variables and demographic characteristics of Von Willebrand Disease patients (n=381) were analyzed and compared between those with type O blood group (205 patients; 54%) and those with type non-O blood groups (176 patients; 46%). Univariate logistic regression was used to obtain crude odds ratios. Predictors with statistically significant p-values were included in a multivariable logistic regression model in order to yield adjusted odds ratio. Statistical significance was set at p<0.05

RESULTS

Patients with O blood groups were less likely to develop VTE (OR 0.29, 95% CI 0.16-0.52, p < 0.001) as compared to Non-O blood groups in which the prevalence of VTE was much higher (25% vs. 9%). Additionally, patients with O blood groups had relatively lower factor 8 activity (125.9±90.8%; OR 0.99, 95% CI 0.99-1.00, p = 0.018) when compared with Non-O blood groups (168.5±120.6%). Patients with O-blood group had significant, life threatening bleeds at an early age (40.4±20.8 years; OR 0.99, 95% CI 0.97-1.00, p = 0.008) when compared with patients with type non-O blood group (Age 47.1±21.9 years). Additionally, O-Blood groups were related to a lesser prevalence of cerebrovascular disease (OR 0.48, 95% CI 0.29-0.79, p = 0.004) and peripheral vascular disease (OR 0.47, 95% CI 0.25-0.87, p = 0.015) as compared to Non-O blood groups.

DISCUSSION

Our study consolidates the fact that vWD patients with O blood group have a lesser risk of developing VTE as compared to non-O blood group patients. Additionally, strokes and peripheral vascular disease is also seen less frequently in O blood groups in patients with Von Willebrand disease. These results suggest that the genes responsible for ABO blood groups also have a significant effect on clinical outcomes in patients with vWD. There are multiple proposed mechanisms to explain this association including presence of ABO antigens on several platelet glycoproteins and glycosphingolipids as well as on the surface of vascular endothelium. More sophisticated, large-scale studies are needed to strengthen the associations we observed in our retrospective study.