Impact of frequent apheresis blood donation on bone density: A prospective, longitudinal, randomized, controlled trial.

Abstract

Blood for transfusion is lifesaving and essential to many elements of modern medical practice. The global blood supply relies on volunteer blood donors. Apheresis is increasingly used to collect blood and requires anticoagulant to prevent extracorporeal coagulation. Citrate, the standard apheresis anticoagulant, chelates ionized calcium with consequent perturbations of serum calcium, parathyroid hormone, vitamin D, and markers of bone remodeling in donors. Cross-sectional studies of bone mineral density (BMD) among apheresis donors exhibit conflicting results. The longitudinal, randomized, controlled ALTRUYST trial (NCT02655055) was undertaken to determine whether BMD declined following high frequency apheresis blood donation over 1 year. The study was powered at 80% to detect the primary outcome of a 3% decline in BMD. Subjects new to apheresis agreed to make ≥20 apheresis donations in a one-year period and were randomized to treatment (high frequency apheresis) or control (no apheresis). Dual-energy x-ray absorptiometry was performed before and after participation. Two-sided <i>t</i>-test and multivariable logistic regression were used to assess outcomes. Mean lumbar spine BMD did not change during the study among control donors (-0.002 g/cm², 95%CI [-0.020, 0.016], <i>p</i> = 0.78), or among donors in the apheresis arm (mean change = 0.007 g/cm², 95%CI [-0.005, 0.018], <i>p</i> = 0.24). Mean total hip BMD did not change for control donors (mean change = 0.002 g/cm², 95%CI [-0.006, 0.009], <i>p</i> = 0.63) or apheresis donors (-0.004 g/cm², 95%CI [-0.10, 0.002], <i>p</i> = 0.16). Tests for differences in proportions of donors with change in BMD exceeding the least significant change at the lumbar spine in either a positive [8 apheresis (31%), 4 control (27%), <i>p</i> = 0.78] or negative direction [4 apheresis (15%), 5 control (33%)] were statistically non-significant (<i>p</i> = 0.18). Proportional increases [0 apheresis (0%), 1 control (7%), <i>p</i> = 0.18] and decreases [3 apheresis (12%), 1 control (14%)] were also not significantly different at the total hip (<i>p</i> = 0.61). ALTRUYST is the first longitudinal trial to demonstrate that apheresis blood collection guidelines in the United States adequately protect the skeletal health of male volunteer blood donors. Marquette University and the BloodCenter Research Foundation.