AHCDO prophylaxis study

Sumit Parikh

Sumit Parikh is the AHCDO ABDR Senior Research Fellow

In the June issue of National Haemophilia, I provided an outline of the large retrospective study conducted last year characterising current prophylaxis practice in patients with haemophilia A and haemophilia B in Australia. At the 2017 Conference I presented the results of this study and an article on the study has been peer reviewed and accepted for publication in the Haemophilia Journal. 

PROPHYLAXIS

Chair: Dr John Rowell
Australian multicentre study of current real-world prophylaxis practice in severe and moderate haemophilia A and B – Dr Jane Mason
ABDR Data analytics – Sumit Parikh 

Key findings
Nationally a total of 718 haemophilia A (551 severe and 79 moderate) patients and 166 haemophilia B (87 severe and 79 moderate) patients were included in the full analysis of the study. Children, adolescents and adults were all represented. Overall 453 patients (82%) with severe haemophilia A were receiving regular prophylaxis, versus 42 patients (25%) with moderate haemophilia A. There were 66 patients (75%) with severe haemophilia B versus 11 patients (13%) with moderate haemophilia B receiving regular prophylaxis.  

Near universal prophylaxis was achieved in the paediatric group. The percentage of patients on prophylaxis was generally seen to decline with increasing age. 

The mean weekly dose of factor VIII for prophylaxis in severe haemophilia A was 84 international units per kilogram per week (IU/kg/week) versus 71 IU/kg/week of factor IX in severe haemophilia B. Overall, rates of patients with severe haemophilia on prophylaxis in Australia are generally comparable with other developed nations. However the mean weekly dose for patients receiving regular prophylaxis appear to be slightly lower than most Western European centres but still within the lower range of the high dose Malmo/Swedish protocol. Mean annual consumption of factor VIII and factor IX for patients with severe or moderate haemophilia A and B was substantially higher for patients on prophylaxis compared to on-demand therapy. Most patients on prophylaxis were treated ≥3 times/week for haemophilia A and 2 times/week for haemophilia B. 

Adherence
Non-adherence in severe haemophilia A patients peaked in the 20 – 29 year (32%) and 30 – 39 year (37%) age group, using less than 75% of the expected amount of factor concentrate. Data for severe haemophilia B demonstrated further reduction in adherence in the 20 – 29 year age group with 50% of patients using less than 75% of expected factor concentrate. 

This study demonstrated that the adolescent and young adult group remain vulnerable during the transition to autonomous health care. It is uncertain whether the less than optimal adherence in this group will have any significant impact on Annual Bleed Rate and joint outcomes. On the other hand it was interesting to note that a subgroup of older individuals on regular prophylaxis used more factor than was expected for their prescribed regimen. The observation that older adults on prophylaxis were routinely prescribed a lower more “intermediate” style dose than their younger counterparts raises the possibility that the additional consumption is to be expected (bleed / surgery / hospitalisation). A very low percentage of haemophilia A and B patients recorded their bleeds on MyABDR app during the study period and as a result reliable Annual Bleed Rates were not obtained. 

The evolution of autonomy in haemophilia care and successful empowerment of patients to self-administer clotting factor concentrates at home has brought with it great improvement in quality of life. A consequence of this is the challenge of balancing autonomy with the need to actively monitor bleed outcome, compliance and track product usage. Future AHCDO projects revolve around these topics hoping to provide further insight and improve our understanding to help deliver better treatment outcomes.