Factor XIII deficiency : preliminary results of the PRO-RBDD project

Background: The PRO-RBDD is a 3-year prospective data collection. Aims: It aims at understanding the association of FXIII activity and clinical severity in patients with FXIII deficiency. Benefits and complications of on-demand and prophylactic treatment were also evaluated. Methods: Data were collected at baseline (historical) and every 6 months (follow-up). 56 patients (31 females, 25 males), of whom 8 children (≤ 12 years) were recorded Results: Regression analysis confirmed a strong association between FXIII levels and age of diagnosis (Pearson test P < 0.05) or clinical severity (classified according to Peyvandi et al, JTH 2012) (b = 12.95, P < 0.05). Grade III bleeding were observed in 87% (20/23) and 67% (8/12) of patients with severe (undetectable activity) and moderate (5–30%) deficiency. More than 1/3 of patients with mild (> 30%) deficiency were asymptomatic and none did have grade III bleeding. Mucocutaneous bleedings, hematoma and haemarthrosis were present in almost 1/3 of patients, regardless their FXIII coagulant levels. More severe symptoms such as CNS, GI and umbilical cord bleeding were observed only in severe and moderate deficiency (13, 4 and 20%). Prophylaxis regimen with plasma-derived FXIII concentrates was used in 2/3 of severe patients and 1/3 of moderates. On 27 women, only 2 had menorrhagia; on 50 pregnancies, 25 ended to a spontaneous abortionand 5 showed bleeding complication. Follow-up data (up to 700 days) on 31 patients on “on-demand” therapy and on 18 on prophylaxis (9–57 U/Kg/month FXIII concentrate) showed an incidence bleeding rate of 1.8 patient-year 1 (95%CI 1.3–2.3) and 0.15 (95%CI 0.02–0.36), respectively. The risk of bleeding requiring replacement therapy is significantly higher in patient on “on-demand” (log rank test = 0.05). No thrombotic events were observed. Conclusion: The PRO-RBDD clearly confirmed the beneficial role of FXIII prophylaxis with no bleeding and no thrombotic events, making this treatment strongly recommended.