|
Study 3 Citation: Primary Prophylaxis in Severe Haemophilia Should Be Started At An Early Age But Can Be Individualized Journal
Institutions
|
Abstract:
Years of clinical practice have demonstrated the effectiveness of prophylaxis in severe hemophilia. Some countries have been using the therapy for the past three decades. And now, with plasma-derived concentrates, it is possible to shorten the infusion intervals and increase the dosage, thereby lessening the impact on quality of life. In addition, new medical devices have helped to provide new administration routes for younger patients. This study takes a look at the debate surrounding prophylaxis, namely the side-effects associated with central venous catheter use, the possibility of severe infections and bleeding. For this study, the researchers compared patient age and dosing when they began prophylactic therapy to clinical outcome. All patients that were considered started therapy before the age of 10 years.
Key words:
Prophylaxis, Arthropathy, central venous access
This study examined how starting various prophylactic regimens in patients with severe hemophilia affects the incidence of joint bleeds and resultant development of arthropathy. In keeping with the theme of this journal club, there were several notable aspects of this study.
Patients were enrolled in this study in three groups: 75 patients started prophylactic treatment before age three; 31 started between three and five years of age; and 15 started between six and nine years of age. Patients were prophylaxed at varying rates per week, and with varying times between treatments ranging from three times weekly to once every three weeks.
In order to allow prophylactic treatment, all patients were taught to give infusions at home. Subjects were evaluated for the number of infusions, joint bleeds and bleeding episodes on a monthly basis.
And while patients enrolled were controlled via the testing mechanisms themselves, there were a few questions that surfaced. Perhaps most importantly, patients were enrolled in this study at various ages and with varying severity of hemophilia. And while the authors did note that there was a distinct advantage seen with those patients that began prophylaxis at an earlier age, patients were admitted into the study at varying ages (up to 10 years old). Additionally, when high-purity concentrates became available, all participants were switched to these. These questions raise inevitable questions as to how their severity affected the outcome of prophylaxis versus on-demand therapy, and how much high-purity concentrates affect general health.
Results:
Results showed an improvement in clotting factor control with the use of more frequent infusions. Joint bleeds in all subjects was 2.6 +/- 0.4 with once-weekly therapy. After switching to a more frequent treatment interval (twice- or three-times-weekly), the number dropped significantly to 1.6 +/- 0.3. Additionally, the researchers found that the group that started prophylaxis earlier, therefore before age three, had noticeably fewer joint bleeds than did the group that started later, between three and five years of age. This was found to be the case without respect to their individual infusion interval. This was the most significant finding of the entire study.
Summary of Study 3
| The authors found that age was an independent predictor for the development of arthropathy, but initial dose and infusion interval were not. The authors noted that severity and frequency of bleeds was directly linked to the number of times and quantity of prophylactic infusions. However, as noted above, the authors key finding was that those children that started infusing prophylactically at an earlier age had "markedly fewer bleeds" than children that started prophylaxis later. |