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

Abstract: IntroductionHaemophilia is a X-linked bleeding disorder affecting mostly males. Women are mainly carriers ofhaemophilia, however, they can expereince high bleeding tendency and assocaited symptoms aswith males. In the absence of the appropriate treatment, bleedings, especially into the joints, result inadverse outcomes. The general aim of this thesis was to promote the use of register-based data toinvestigate long-term outcomes among persons with haemophilia. In addition, we investigated somelong-term ouctomes among persons with haemophilia and carriers of haemophilia using the availableregisters.MethodsWe conducted a scoping study and several large-scale register-based studies to evaluate outcomeassessment practice and joint and survival outcomes in haemophilia, respectively. We used data fromthe Malmö single centre register (n=167), National Patient Register (mild haemophilia=315 andcarriers of haemophilia=561) and the KAPPA register (severe haemophilia=173) as sources ofinclusion of participants and data on their outcomes. Cross-sectional and longitudinal designs wereused to maximize the use of available data. We investigated joint disease, haemophilia joint healthscore, joint surgery and survival of the study participants.Results and conclusionThe assessment of the literature revealed a paucity of productive registers and inconsistency in theiroutcome reporting. Carriers and persons with mild haemophilia are at higher risk of joint disease andsurgery compared to the general population. The index joints are more at risk of surgery in bothgroups especially among the older age groups. The KAPPA study showed remarkable health utilityand joint status among younger persons with severe haemophilia on prophylaxis started by age 3. Inthe 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 riskof 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 resourcesfor generation of epidemiological evidence.