A new study based in Canada revealed the utility of magnetic resonance imaging (MRI) in evaluating joint changes in boys with severe hemophilia A, with more than one-third of patients showing joint changes even with dose- or frequency-adjusted prophylaxis. The study results were published in the journal Research & Practice in Thrombosis & Haemostasis.

The study was performed as a component of the Canadian Hemophilia Prophylaxis Study. This analysis included boys from 1 to 2.5 years of age who had severe hemophilia A. These patients received frequency/dose-escalated primary prophylaxis with recombinant factor VIII according to bleeding criteria. They underwent study visits at 3-month intervals for the initial 5 years of study, at which time the visits were switched to every 6 months.

X-ray and MRI evaluations of 6 index joints were conducted at interval and end-of-study time points, with the interval MRI occurring when the child was at age 6 and the end-of-study MRI occurring at age 12 (+ 2 years). End-of-study MRI findings of osteochondral changes were the primary study outcome. Secondary outcomes involved findings of index-joint bleeds and whether bleeding and MRI findings at intervals were predictors of joint deterioration.

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A total of 46 patients were evaluated through the end-of-study MRI assessment, with a median follow-up of 9.6 years (range, 4.8-16). At the end-of-study assessment, these patients had a median age of 11.4 years (range, 6.2-18.5). A total of 27 of the patients had both interval and end-of-study MRI assessments.

The end-of-study MRI findings revealed that 39% of evaluated patients showed osteochondral changes in 1 or more of the index joints. Among these patients with osteochondral changes, 44% showed changes in more than 1 joint.

The presence of self-reported joint bleeding between the interval and end-of-study MRI assessments was linked to a nearly 50% increase in the likelihood of worsening of the joint condition (odds ratio, 1.49; 95% CI, 1.08-2.06). Synovial hypertrophy or hemosiderin seen during the interval MRI were linked to significantly greater odds of osteochondral damage visible by later MRI and by X-ray.

“Dose-and frequency-adjusted prophylaxis did not completely prevent the progression of MRI-detected joint changes in boys with hemophilia, with 39% of subjects developing objectively determined joint changes, most notably in ankles and elbows,” the researchers wrote in their report. They concluded that serial imaging, such as by MRI, may be useful in guiding prophylaxis strategies for this patient population.

Disclosures: Some authors have declared affiliations with or received grant support from the pharmaceutical industry. Please refer to the original study for a full list of disclosures.


Stimec J, Dover S, Pullenayegum E, et al. Magnetic resonance imaging in boys with severe hemophilia A: serial and end-of-study findings from the Canadian Hemophilia Primary Prophylaxis Study. Res Pract Thromb Haemost. 2021;5(7):e12565. doi:10.1002/rth2.12565