Status and risk factors of inhibitor occurrence in single-center children with hemophilia

Objective To investigate the cumulative incidence and risk factors of inhibitor occurrence in Chinese children with hemophilia in Beijing Children′s Hospital(BCH), and provide the basis for developing control strategies for Chinese children with hemophilia inhibitor. Methods To know the cumulative incidence of inhibitor, outcome and associated risk factors of hemophilia by collecting patients′ data from November 2012 to December 2013 at BCH hemophilia professional clinic, ≤20 exposure days (ED), continuity detecting inhibitor at fixed point time as much as possible from November 2012 to April 2015. Results Forty-eight cases were enrolled, and the median duration was 30(14-71) months and the median exposure time was 7(1-20) days; these patients consisted of 3 (6.3%) mild cases, 17 (35.4%) moderate cases and 28 (58.3%) sever cases.The cumulative incidence of inhibitors was 27.1%(13/48 cases) with 172 times of detecting in which the median time of follow-up was 24(15-29) months and 20(5-150)ED.The occurrence of low titer inhibitor was 30.8% (4/13 cases), and for high titer inhibitors it was 69.2% (9/13 cases). To rescue life-threatening bleeding was the reason for the first time exposure [OR=6.67, 95%CI (1.31-33.94), P<0.05] and ED within the 20 ED[OR=5.19, 95%CI (1.02-26.94), P<0.05] were the related risk factors of inhibitors, but exposure days within the 20 ED [OR=8.53, 95%CI (1.46-50.05), P<0.05] was associated with the formation of high titer inhibitors. Conclusions The inhibitor cumulative incidence of hemophilia A was 27.1%, in which high titer inhibitors accounted for 2/3.To rescue life-threatening bleeding as the reason for the first time exposure and ED within the 20 ED are the related risk factors of inhibitors. Key words: Child; Hemophilia A; Inhibitor