Study On Long-term Joint Outcome Of Low Dose Prophylaxis For Children With Severe Hemophilia A

ObjectivesThe short-term application of low dose prophylaxis can significantly reduce the number of joint hemorrhage,but the long-term joint protective effect has not been reported.In this study,children with severe hemophilia A who received regular low-dose prophylaxis were followed up for a long time,the long-term joint outcome under low-dose prophylaxis was studied,and the related factors affecting joint outcome were preliminarily discussed.MethodsThe clinical data of 21 children patients with severe hemophilia A who received regular low dose prophylaxis in Hemophilia Clinic of Peking Union Medical Hospital were collected.These patients were followed up for a long period of 6-10 years.The age of the children and the age of starting low dose prophylaxis treatment were counted.We also have collected the follow-up-time,Low-dose prophylaxis time(annual number of weeks),dose of Low-dose prophylaxis,quality of life score,annual joint bleeding rates(AJBR),etc.Using joint Magnetic resonance Imaging score(IPSG MRI score),Hemophilia Joint Health Score(HJHS)target joint numbers and other indicators to evaluate the state of joint in children from multi-dimensional degree,such as joint structure and function,and the possible influencing factors of long-term joint outcome were preliminarily analyzed by statistical method.Result(1)The age of 21 children starting low dose prophylaxis was(10.61 ±3.83)years old,the follow-up time was(8.00±0.80)years,the age of termination was(18.1±4.44),and the dose of treatment used for low dose prophylaxis was(24.75±11.25)IU/kg.W,low dose prophylaxis time(average annual number of weeks)(19.63±18.36)Week/year,AJBR for(17.84±11.61)times/year.(2)The IPSG MRI score in 21 patients was(13.52±6.17),of which 47.6%of the patients had mild moderate involvement in the joints,52.4%had severe joint involvement.HJHS joint score averaged 14 points(0-27).There was 8/15 cases(53.3%)that the HJHS ranged of 0-13 points.37 target joints were formed on demand,and the number of target joints decreased by 32.4%after long-term low dose prophylaxis,no one need to use assistive device,no one had joint deformity.81%of patients' daily life was not affected,81%of children were full attendance at school,76.2%of children had more than 3 days of exercise per week,of which 61.9%of children exercise time of more than 30 minutes.(3)There was a positive correlation between the MRI score of joint IPSG?HJHS and the target joints(p<0.05).There was a significant positive correlation between IPSG MRI score and the age of initiation of low dose prophylaxis and AJBR(p<0.05),IPSG MRI score was significantly negatively correlated with the therapeutic dose used in low-dose prophylaxis(p<0.05);HJHS Joint score was negatively correlated with the time of low dose prophylaxis and the therapeutic dose of low dose prophylaxis(p<0.05),which was positively correlated with age of initiation of low dose prophylaxis and AJBR(p<0.05).There was a significant positive correlation between the MRI score of Joint IPSG and HJHS(p<0.05),which showed that the joint structure and function evaluation were consistent.Conclusions:(1)Long term low-dose prophylaxis can reduce the number of target joints,reduce the use of walking aids,protect joint function and improve the quality of life of children compared with on-demand treatment.(2)Low-dose prophylaxis can make nearly half of patients,whether joint structure,function,or quality of life,similar to the effect of high-dose preventive treatment,indicating the feasibility of low-dose prophylaxis.(3)However,more than half of the patients' joint structure,function and quality of life slightly lower than the high dose of prophylaxis,joint outcome is not ideal.So it is needed to adjust the treatment plan in time.We advocate individualized treatment to improve joint outcomes in all aspects.(4)It is recommended that children start prophylaxis as early as possible,and extend the time of preventive treatment as far as possible,using higher doses of prophylaxis,can effectively reduce the rate of joint bleeding,reduce joint damage,protect joint function,and ultimately improve the long-term joint outcome.