Abstract Number: OC 27.1
Meeting: ISTH 2022 Congress
Background: Few data exist on long-term follow-up of type and frequency of bleedings in children 0-18 years with severe hemophilia on primary prophylaxis with FVIII/FIX.
Aims: Comparison of reported bleeds in real-world data between different age groups in children with severe hemophilia A (SHA) or B (SHB) on primary prophylaxis.
Methods: The PedNet registry is a multicenter prospective observational cohort study (Clin.gov.trial NCT02979119). For this study we included all children with SHA or SHB without history of inhibitors born between 2000-2020. Data of all bleeds were collected from the start of prophylaxis until January 2021. Bleeds were defined according to the ISTH definition. Bleeding severity was defined as minor when characterized by mild pain, minimal swelling, minimal motion restriction and resolving within 24 hours of treatment, and as major when symptoms persisted >24 hours. Annual bleeding rate (ABR) was based on reported bleeds, using a negative binominal model. Patients were divided into three age groups: 0-5 years, 6-11 years, and 12-18 years.
Results: We included 737 children with SHA and 133 with SHB. The total follow-up years on prophylaxis for SHA was 5838, median 7.5, (IQR 4.0-11.6) and for SHB 1042 years, median 7.7 (IQR 3.7-11.1). Total ABR was 2.8 for SHA and 2.0 for SHB, major joint bleeds were a median (IQR) of 0.36 (0.30-0.43) for SHA and 0.28 (0.21-0.37) for SHB over all three age groups. Minor joint bleeds were a median (IQR) 0.56 (0.51-0.61) for SHA and 0.42(0.34-0.52) for SHB. Minor other bleeds were reported as 1.9 (1.7-2.1) for SHA 1.4(1.1-1.7) for SHB and between 0-5 years (Figure 1).
Conclusion(s): Primary prophylaxis was equally protective in all groups. Reported bleeds in SHB were lower in all groups. In younger patients, the higher reporting of minor bleeds might reflect inadequate prophylaxis or high parental anxiety.
To cite this abstract in AMA style:van den Berg H, Alvarez Roman M, Carcao M, Chambost H, Fischer K, Grentenkort-Andersson N, Kenet G, Königs C, Ljung R, Male C, Motwani J. The type and frequency of bleeds in 870 children with severe hemophilia A and B on primary prophylaxis: Data from the PedNet study group [abstract]. https://abstracts.isth.org/abstract/the-type-and-frequency-of-bleeds-in-870-children-with-severe-hemophilia-a-and-b-on-primary-prophylaxis-data-from-the-pednet-study-group/. Accessed September 29, 2023.
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