Patient-reported data on the severity of Von Willebrand disease.

Introduction: The severity of Von Willebrand disease (VWD) is currently based on laboratory phenotype. However, little is known about the severity of the patient's experience with the disease. The most recent VWD guidelines highlight the need for patient-reported outcomes (PROs) in VWD.

Aim: The study aimed to investigate the patient-perspective on VWD severity and to identify key factors that determine the severity of disease experienced by patients.

Materials and methods: Patients participated in a nationwide cross-sectional study on VWD in the Netherlands (WiN-study). Patients filled in a questionnaire containing questions on the experienced severity of VWD (4-point scale), bleeding score (BS) and quality of life (QoL).

Results: We included 736 patients, median age of 41.0 years (IQR 23.0-55.0) and 59.5% were women. A total of 443 had type 1, 269 type 2 and 24 type 3 VWD. Self-reported severity of VWD was categorized as severe (n = 52), moderate (n = 171), mild (n = 393) or negligible (n = 120). Classification by historically lowest FVIII:C levels < 0.20 IU/mL as a proxy for severe VWD aligned with patient-reported severity classification with a 72% accuracy. Type 3 VWD (OR = 4.02, 95%CI: 1.72-9.45), higher BS (OR = 1.09, 95%CI: 1.06-1.11), female sex (OR = 1.36, 95%CI: 1.01-1.83), haemostatic treatment in the year preceding study inclusion (OR = 1.53, 95%CI: 1.10-2.13) and historically lowest VWF:Act levels (OR = 0.26, 95%CI: 0.07-1.00) were independent determinants of patient-reported severity.

Conclusion: This study shows that patient-reported data provide novel insights into the determinants of experienced disease severity. Our findings highlight the need for studies on PROs with validated questionnaires to assess the burden of VWD.