Body mass index (BMI; calculated as the weight in kilograms divided by height in meters squared) may be associated with increased levels of von Willebrand factor (VWF) and factor VIII (FVIII), though it confers no protection against bleeding in patients with von Willebrand disease (VWD), according to research published in the American Journal of Hematology.

Researchers enrolled 545 patients with VWD; 349 patients had type 1 VWD and 196 patients had type 2 VWD. Blood samples were collected from the patients at inclusion, and patients filled out a questionnaire. Patients were also categorized as being underweight (13 patients), normal weight (276 patients), overweight (175 patients), or obese (81 patients). BMI thresholds for being underweight, normal weight, overweight, or obese were below 18.5, 18.5 to 25, 25 to 30, and greater than 30, respectively.

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Patients in both groups had similar mean BMI scores (25.5 in type 1 vs 25.2 in type 2; P =.550). Higher BMI was associated with increased levels of VWF:Ag and FVIII:C in patients with both type 1 and type 2 VWD, as well as with increased levels of VWF:CB and VWF:Ab in patients with type 1 VWD.

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Bleeding episodes requiring hemostatic treatment occurred in 25% of patients with normal weight compared with 30% of patients who were overweight and 38% of patients who were obese (P =.018) in the year prior to inclusion in the study.

In both cohorts, more patients who were obese experienced bleeding episodes compared with patients with normal weight. For type 1 disease, the relative risk was 1.8 (P =.034; adjusted odds ratio, 1.91). For type 2 disease, the relative risk was 1.4 (P =.113). No association was found between BMI and total bleeding score in either group.

The authors concluded that despite having higher levels of VWF, “overweight and obese patients with VWD are not protected against bleeding and still need to receive prophylactic treatment during interventions.”

Disclosures: Some authors have declared affiliations with the pharmaceutical industry. Please refer to the original study for a full list of disclosures.


1.     Atiq F, Fijnvandraat K, van Galen KPM, et al. BMI is an important determinant of VWF and FVIII levels and bleeding phenotype in patients with von Willebrand disease [published online April 29, 2019]. Am J Hematol. doi:10.1002/ajh.25499