Hypercalcemia in rheumatoid arthritis: relationship with disease activity and bone metabolism.
To investigate the relationship between ionized calcium and disease activity, parameters of bone metabolism and bone mineral density (BMD) at the lumbar spine (BMD-LS) and the femoral neck (BMD-FN) measured by dual X-ray absorptiometry in rheumatoid arthritis (RA). In 146 patients with RA, the following parameters were investigated: serum levels of ionized calcium, total calcium, vitamin D metabolites 25-hydroxyvitamin D3 (25D3) and 1,25-dihydroxyvitamin D3 (1,25D3), intact parathyroid hormone (iPTH), interleukin-6, osteocalcin, erythrocyte sedimentation rate (ESR) and c-reactive protein (CRP); renal excretion of pyridinolin (PYD)- and desoxypyridinolin (DPD)-crosslinks. A total of 30.1% of the patients were hypercalcemic (ionized calcium >1.30 mmol/l). In comparison with normocalcemic patients, those with hypercalcemia had significantly higher ESR (P<0.01) and CRP values (P<0.05) and significantly lower serum levels of both iPTH (P<0.01) and 1,25D3 (P<0.05) and a significantly lower BMD-LS (P<0.05). The results indicate that a substantial part of RA patients is hypercalcemic. Hypercalcemia is associated with high disease activity and may contribute to suppression of PTH secretion and vitamin D hormone synthesis. High levels of ionized calcium may be a reflection of disease-activity-related systemic bone loss, and could be a predictor of BMD at the lumbar spine in RA.
Oelzner
Peter
P
Department of Internal Medicine III, Division of Rheumatology/Osteology, Friedrich-Schiller University, Erlanger Allee 101, 07740 Jena, Germany. peter.oelzner@med.uni-jena.de
Lehmann
Gabriele
G
Eidner
Thorsten
T
Franke
Sybille
S
Müller
Andreas
A
Wolf
Gunter
G
Hein
Gert
G
D015502:Absorptiometry, Photon; D000293:Adolescent; D000328:Adult; D000368:Aged; D000596:Amino Acids / Q000737:chemistry / Q000652:urine; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001799:Blood Sedimentation; D015519:Bone Density; D001851:Bone Diseases, Metabolic / Q000097:blood*; D002097:C-Reactive Protein / Q000032:analysis; D002112:Calcifediol / Q000097:blood; D002117:Calcitriol / Q000097:blood; D002118:Calcium / Q000097:blood; D003432:Cross-Linking Reagents / Q000737:chemistry; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging / Q000378:metabolism*; D006801:Humans; D006934:Hypercalcemia / Q000097:blood / Q000503:physiopathology*; D015850:Interleukin-6 / Q000097:blood; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood; D010281:Parathyroid Hormone / Q000097:blood; D012709:Serum Albumin / Q000032:analysis
D000596:Amino Acids; D003432:Cross-Linking Reagents; D015850:Interleukin-6; D010281:Parathyroid Hormone; D012709:Serum Albumin; D015675:Osteocalcin; C015484:pyridinoline; C036020:deoxypyridinoline; D002097:C-Reactive Protein; D002117:Calcitriol; D002112:Calcifediol; D002118:Calcium