Hemophilia without prophylaxis: Assessment of joint range of motion and factor activity

Background Recurrent joint bleeding in hemophilia results in arthropathy and functional impairment. The relationship of arthropathy development and factor activity (FA) has not been reported in patients with FA levels 10% less than controls; those ≥40 years old with FA 20% less than controls. In the multivariable analysis, subjects with <1% FA had a 0.43% greater decrease (-0.49 to -0.37, 95% confidence interval) in PN-ROM each year relative to those with 16%-40% factor activity. A less pronounced effect was seen with 1%-5% or 6%-9% FA. Conclusion The effect of FA on ROM loss is far greater than that of any of the other characteristics, especially with FA <10%. This emphasizes the need to maintain a high index of suspicion for arthropathy in individuals with moderate and low-mild hemophilia.