ORLANDO – The frequency of prophylactic clotting factor infusions does not appear to adversely affect adherence to hemophilia therapy in children, but age seems to play a role in compliance to prescribed regimens, investigators in two separate studies report.
A study of pediatric patients with moderate to severe hemophilia A or B on bleeding prophylaxis showed no significant differences in adherence between patients receiving two clotting factor infusions per week and those receiving three or four per week, reported Karen Strike, a physiotherapist at McMaster Children’s Hospital in Hamilton, Ont., and colleagues.
Karen Strike
“This study demonstrates that our patients have a very high degree of adherence, and it doesn’t appear to be related to infusion frequency,” she said in an interview at a scientific poster session at the World Federation of Hemophilia World Congress.
Although their sample size was small – just 23 patients – the median levels of adherence were high for both twice-weekly infusers (99.5%) and 3-4 times per week infusers (96%; P = .053).
Ms. Strike acknowledges that the borderline P value could be due to the small sample size instead of a lack of association. Additionally, because the patients are managed by a regional hemophilia treatment center, they tend to be more engaged and more likely to cooperate with clinician instructions, she said.
“Basically, patients are either going to do what’s prescribed or they’re not. What that actual prescription is doesn’t seem to matter. If they prescribe you twice a week or they prescribe me every other day, you’re going to be adherent to twice a week or you’re not.
The investigators have expanded their study to include adult patients on primary prophylaxis and to look at additional co-variates that might have an effect on adherence, including interactions with a health care team, geographical distance from a hemophilia treatment center, joint health status, and infusion delivery method (peripheral vs. port).
Age may be a factor
In a separate study, German investigators report that adherence appears to vary by age.
Wolfgang Miesbach, MD, from Goethe University Hospital in Frankfurt, Germany, and colleagues asked all members of the German hemophilia patient organization with moderate or severe hemophilia to fill out the VERITAS-PRO (Validated Hemophilia Regimen Treatment Adherence Scale-Prophylaxis) questionnaire and compared scores across age groups.
Data were available on a total of 364 patients. The investigators found that among 131 children from birth to age 19, adherence to prescribed regimens was 100%. In contrast, the adherence rate among 189 adults aged 20-59 was 88.1%. After age 59, adherence rates began to improve as those 60 and older (44 patients) reported 93.9% adherence.
“Within the patients aged 20+, care by a hemophilia center was the only significant indicator for better adherence. The tendency of better adherence of patients aged greater than 60 compared to patients 20-59 may be explained by the significant association of the occurrence of pain with increasing age although a significant influence of pain on the adherence levels could not be demonstrated,” the investigators wrote.
Their findings point the way to possible interventions to facilitate adherence to prophylaxis among patients with hemophilia, they wrote.
Both studies were internally funded. The authors reported no relevant disclosures.