By Dr. David Clark

1/19/24  Mild hemophilia (factor levels between 5 and 50% of normal) has not usually been considered to involve spontaneous joint bleeds or joint damage. A 2018 study among the U.S. Hemophilia Treatment Centers (HTCs) predicted that the annualized joint bleeding rate (AJBR) for a 25- to 44-year-old male with a factor IX level of 20% would be about 0.5.  That is, he would only have about one joint bleed in two years.  However, a 2012 Canadian study using MRI found damage in more than 30% of joints that had no previous history of bleeds.  Thus, the concern is that people with mild hemophilia may be accumulating joint damage, even when they have no obvious bleeds. 

A study looking at 70 mild hemophilia patients (57 males and 13 females) from the Yale HTC in Connecticut found 20 (28.6%) patients with a history of joint bleeding, 13 traumatic bleeds (bleeds caused by trauma) and seven spontaneous (with no apparent cause) bleeds.  The average age at their first joint bleed was 20.8 years (range 4 to 58).  Ten patients developed bleeds between the ages of 10 and 20.  The most common locations of bleeds were the knee (11 patients) and the ankle (7 patients).  For unknown reasons, three-quarters of the patients with HCV had joint bleeds. 

The bottom line is that about 15% of mild patients had abnormal joints, even without a history of joint bleeds.  This shows the need for ongoing evaluation of joint health in people with mild hemophilia.  [Chiara JB et al., Haemophilia, online ahead of print 1/19/24]