Risk factors for future bleeding in patients with mild bleeding disorders: longitudinal data from the Vienna Bleeding Biobank.

Background: The future bleeding risk, especially after hemostatic challenges, and thus the requirement for hemostatic treatment in patients with mild-to-moderate bleeding disorders (MBDs) is largely unknown.

Objectives: This study aimed to prospectively examine the recurrence of bleeding symptoms and clinical risk factors for future bleeding in patients with MBD, including patients with bleeding disorder of unknown cause (BDUC).

Methods: Bleeding symptoms of patients with MBD included in the Vienna Bleeding Biobank were re-evaluated at in-person follow-up visits or by mail.

Results: In total, 392 patients, including 62.8% with BDUC, were investigated for the recurrence of bleeding events. During the follow-up time of median (IQR) 4.3 years (2.6-6.7), 72% of patients had at least 1 bleeding event. Most persistent bleeding manifestations were hematomas (n = 146/245, 59.6%) and bleeding from small wounds (n = 69/141, 48.9%), followed by epistaxis (n = 42/132, 31.8%), oral mucosal bleeding (n = 26/87, 29.9%), and joint bleeding (n = 7/14, 50.0%). Patients with previous postinterventional bleeding had a significantly increased risk for bleeding events after surgery (n = 33/114, 29.0 %) or tooth extraction (n = 16/39, 41.0%). A high bleeding score (OR [95% CI], 1.14 [1.05 to 2.94], per 1 unit) and follow-up time (OR [95% CI], 1.23 [1.12 to 1.36], per 1 year) were independently associated with any bleeding event. For bleeding after hemostatic challenges, blood group O (OR, 3.17 [1.57 to 6.40]), previous postsurgical bleeding (OR, 2.40 [1.06 to 5.46]), and an established diagnosis (OR, 2.07 [1.04 to 4.10]) were independent risk factors.

Conclusion: Patients with MBD have a high risk for recurrent bleeding. This encourages prophylactic hemostatic treatment in patients with MBD, particularly when they face hemostatic challenges.