Treatment outcomes in persons with severe haemophilia B in the Nordic region: The B‐NORD study

Abstract

Introduction Data on outcome in persons with haemophilia B (PwHB) are limited and mainly extrapolated from studies of haemophilia A (HA). Aim To characterize treatment outcomes in persons with severe HB in the Nordic region, with a focus on joint health, compared with matched controls with HA. Methods PwHB attending haemophilia centres in Denmark, Finland, Norway and Sweden were enrolled and matched with controls with HA. Joint assessment using Haemophilia Joint Health Score (HJHS) and ultrasound according to Haemophilia Early Arthropathy Detection protocol (HEAD‐US) was conducted. Adherence was evaluated using the Validated Haemophilia Regimen Treatment Adherence Scale (VERITAS). Results Seventy‐nine males with HB, with median age of 30 years (range 1–75), were enrolled. Eleven patients (14%) had a history of or current inhibitor. Twenty‐nine PwHB (37%) reported joint bleeds during the prior year, and 35% had previously undergone joint surgery. Ninety‐five per cent were on prophylaxis, and 70% used recombinant concentrates, with a median factor consumption of 3,900 IU/kg/year for standard half‐life products. Only two patients had a VERITAS score corresponding to ‘non‐adherence'. Joint health, assessed with HJHS, showed a significant lower score among PwHB compared with HA controls, explained by a difference in the 18–49 age group, without observed differences in older or younger subgroups. The HEAD‐US scores were overall low. Conclusion The Nordic cohort of PwHB is well treated by prophylaxis, but the goal of zero bleeds for all is not reached. Our findings suggest that patients with severe HB suffer from a milder arthropathy than patients with severe HA.

No difference in quality of life between persons with severe haemophilia A and B

“…The observational study B‐NORD has been described previously 1 and enrolled persons registered at HTCs in Denmark, Finland, Norway and Sweden with a confirmed diagnosis of congenital severe HB (FIX level < .01 IU/ml). Control persons with severe HA matched by age, gender and treatment modality (on demand/prophylaxis) from one of the Nordic HTCs were identified using the KAPPA register 9 .…”

“…Consequently, much of our knowledge on HB has been extrapolated from studies based on persons with HA (PwHA). The B‐NORD study 1 was designed with HB patients in mind, to better understand the disease, its similarities to and differences from HA, and to further improve and individualize the care of HB patients.…”

Haemophilia specialist nurses’ perceptions of haemophilia B

“…However, such differences have not always been clearly demonstrated. Although milder arthropathy is reported in haemophilia B [3] , there appears to be little difference in health-related outcomes between the disorders. One survey of people with severe haemophilia A or B between 1998 and 2013, when treatment largely comprised on-demand factor replacement, found no significant difference in major bleeding events or resulting admissions [4] .…”

Factor IX antibodies and tolerance in hemophilia B in the Nordic countries – The impact of F9 variants and complications

“…The B-NORD study is an observational multicenter study conducted in Denmark, Finland, Norway and Sweden and has been described previously [18]. Individuals of all ages with severe congenital HB were enrolled between the years 2017 and 2020.…”

“…Out of 108 persons with severe HB registered at the study centers, 79 (73 %), median age 30 years (Q1-Q3 19-53), were enrolled in the B-NORD study [18]. Patient characteristics are presented in Table 1.…”