Apheresis affects bone and mineral metabolism.
BACKGROUND
Apheresis is a procedure to selectively obtain blood components. For the collection process citrate is routinely used. It inhibits coagulation by binding to ionized calcium and leads to metabolic alkalosis.


OBJECTIVE
Whether regular apheresis affects bone and mineral metabolism is unknown. The intention of this study was to investigate 1) the acute effects of apheresis on acid-base balance, bone and mineral metabolism and 2) to compare bone mineral density (BMD) at the lumbar spine and hip of donors to matched control subjects.


METHODS
In this open, observational, single-center, cross-sectional study we enrolled 102 regular plasma and thrombocyte donors to pursue objective 1) and compared those to 102 matched controls (CTR) for objective 2).


RESULTS
Platelet donation led to significant decreases in serum ionized calcium (-17%) and phosphate (-18%), to marked increases in base excess (57%) and PTH levels (192%) during apheresis. Baseline biochemical comparisons between donors and CTR revealed significantly lower values for donors for serum calcium, albumin, and 25-hydroxyvitamin D levels. Mean Z-score at the lumbar spine adjusted for BMI, average physical activity and daily calcium intake was lower for donors (-0.28+/-0.11) when compared to CTR subjects (0.06+/-0.11, P<0.05). Total and neck femoral BMD was also lower in the donor group, however, this difference was not significant.


CONCLUSIONS
Exposure to citrate during the apheresis procedure acutely affects mineral and bone metabolism. Regular donations of blood components compromised BMD at the lumbar spine. If confirmed, strategies to prevent long-term effects on bone need to be formulated.
Amrein
Karin
K
Department of Blood Group Serology and Transfusion Medicine, Medical University of Graz, Austria. karin.amrein@klinikum-graz.at
Katschnig
Claudia
C
Sipurzynski
Sabine
S
Stojakovic
Tatjana
T
Lanzer
Gerhard
G
Stach
Elisabeth
E
Pieber
Thomas R
TR
Dobnig
Harald
H
D000136:Acid-Base Equilibrium / Q000502:physiology; D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D001782:Blood Donors; D015519:Bone Density / Q000502:physiology*; D003430:Cross-Sectional Studies; D004573:Electrolytes / Q000097:blood; D005260:Female; D005272:Femur Neck / Q000378:metabolism; D006801:Humans; D008159:Lumbar Vertebrae / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010956:Plasmapheresis / Q000009:adverse effects*; D010983:Plateletpheresis / Q000009:adverse effects*
D015415:Biomarkers; D004573:Electrolytes