Prophylaxis usage, bleeding rates, and joint outcomes of hemophilia, 1999 to 2010: a surveillance project
Joint arthropathy in hemophilia is caused by recurrent hemorrhage into joints and ultimately may lead to destruction of the joint, chronic pain, and limited function which ultimately impacts on patient quality of life and employment. Prophylaxis has been shown to prevent joint bleeding and arthropathy. The adoption of prophylaxis in the US and Canada has increased in all age groups but generally has been greater in younger age groups compared to adults.
The Universal Data Collection (UDC) system collected predefined data from the annual visits of hemophilia patients from 134 US Hemophilia Centers. Data was analyzed in a cross-sectional manner for each study year as well as longitudinal analysis performed on data from participants who had more than 1 clinic visit during the study period.Data was collected from 6196 males with severe hemophilia A. Longitudinal data were available for 3078 participants.
Joint bleeding rates fell by 22% in prophylaxis patients during the study period. A similar decrease (23%) was noted in nonprophylaxis individuals, however the rates of joint bleed and total bleeding events were twice that of patients on prophylaxis. The number of target joints and the rate of target joint bleeding fell significantly in both prophylaxis (80% reduction) and nonprophylaxis (60% reduction) groups. Over time, joint range of motion (ROM) decreased with age regardless of prophylaxis. Decreased rate of joint ROM loss was significantly associated with primary prophylaxis institution before 4 years of age while it was increased by obesity.
The cross-sectional data could limit the conclusions regarding the association between prophylaxis use and decreased bleeding rates but the longitudinal analysis of a smaller group mitigates this weakness. In addition, bleed events were by patient self-report. Interestingly, the nonprophylaxis groups also displayed improved joint outcomes but the reasons for this are unclear - it is hypothesized that the group, over time, may have lost patients to prophylaxis, while other factors such as increased education, and effect of study surveillance may have affected the use of on-demand treatment and preventive measures in both groups.