Register-based studies to assess long-term outcome in haemophilia

Introduction
Haemophilia is a X-linked bleeding disorder affecting mostly males. Women are mainly carriers of
haemophilia, however, they can expereince high bleeding tendency and assocaited symptoms as
with males. In the absence of the appropriate treatment, bleedings, especially into the joints, result in
adverse outcomes. The general aim of this thesis was to promote the use of register-based data to
investigate long-term outcomes among persons with haemophilia. In addition, we investigated some
long-term ouctomes among persons with haemophilia and carriers of haemophilia using the available
registers.
Methods
We conducted a scoping study and several large-scale register-based studies to evaluate outcome
assessment practice and joint and survival outcomes in haemophilia, respectively. We used data from
the Malmö single centre register (n=167), National Patient Register (mild haemophilia=315 and
carriers of haemophilia=561) and the KAPPA register (severe haemophilia=173) as sources of
inclusion of participants and data on their outcomes. Cross-sectional and longitudinal designs were
used to maximize the use of available data. We investigated joint disease, haemophilia joint health
score, joint surgery and survival of the study participants.
Results and conclusion
The assessment of the literature revealed a paucity of productive registers and inconsistency in their
outcome reporting. Carriers and persons with mild haemophilia are at higher risk of joint disease and
surgery compared to the general population. The index joints are more at risk of surgery in both
groups especially among the older age groups. The KAPPA study showed remarkable health utility
and joint status among younger persons with severe haemophilia on prophylaxis started by age 3. In
the Malmö register study, persons with severe haemophilia born 1980 onwards did not have surgery.
This thesis suggests that carriers of haemophilia and persons with mild haemophilia are at high risk
of joint disease and should be monitored at haemophilia treatment centres for their outcomes.
Registers, when harmonized in terms of structure and outcome assessment, are valuable resources
for generation of epidemiological evidence.