Bone density as outcome parameter in haemophilia treatment

Haemophilia A and B are congenital and X-linked disorders caused by deficiency
or dysfunction of clotting factor VIII (haemophilia A) and factor IX
(haemophilia B). In severe haemophilia A or B, patients typically exhibit
apparently spontaneous bleeding. Joint bleeds are characteristic and if the
patients are untreated, permanent joint damage (haemophilic arthropathy) and
disability can result. In Sweden and the Netherlands, prophylactic replacement
therapy with factor VIII and IX has been given since the 1970s. Both countries
have reported favourable results, but treatment dose has been twice as high in
Swedenm, resulting in a higher annual treatment cost (mean 240.000 vs 120.000
Euro /patient/yr).
In Norway, prophylactic treatment was only introduced recently.
There remains a lack of consensus regarding long-term treatment evaluation of
patients with haemophilia. One way is to compare the patient*s long-term
consumption of health care. Our hypothesis is that bone density measurement
could be a clinical tool to evaluate the patient*s physical activity and
quality of life over the years. There are several studies of non-haemophilic
patients that have shown it is important to begin physical activity early in
life to reduce the risk of fracture. Haemophilic patients with frequent bleeds
are generally more inactive than haemophilic patients with fewer bleeds or
those who are well treated, and they are at risk for reduced bone mineral
density because of decreased physical activity. Bone density has the potential
to be an objective, long term outcome measure of haemophilic treatment. Thus,
the overall goal of this study is to evaluate the utility of bone density as an
indicator for treatment qualityand to study its association with physical
activity.

• Compare bone density between patients with mild haemophilic and those with
severe haemophilia*.
• Compare the relationship between treatment regimen: prophylactic (high-dose
vs. intermediate dose) and on-demand and bone density.
• Examine the association between physical activity and bone density in
patients with severe haemophilia.


* Dutch patients will not contribute here, as only severe patients will be
included.

Cross sectional comparison of cohorts from Sweden, Norway and the Netherlands.

As many data were already collected for a previous study of Swedish and Dutch
patients (METC UMCU 06-002) and the additional outcome parameter of BMD may be
a valuable addition, we have decided to only include patients who already
participated in this study. Therefore the patient burden is only signing
informed consent and undergoing a BMD (DEXA) scan of 30 min duration with
minimal radiation.
The risk asssociated with participation appears very low (minimal).