Bone mineral density and parathyroid function in patients on maintenance hemodialysis.
BACKGROUND
The relationship between parathyroid function, an important determinant of bone turnover, and bone mineral density (BMD) in patients with chronic kidney disease is not fully understood. We wanted to analyze the association between BMD and parathyroid function in hemodialysis patients in details.


METHODS
In a cross-sectional design, data from 270 patients (age 55 ± 15 years, 60% men, all Caucasian) on maintenance hemodialysis were analyzed. All patients underwent dual energy X-ray absorptiometry of the lumbar spine (LS), femoral neck (FN) and distal radius (DR). In addition to routine laboratory tests, blood samples were collected for iPTH, serum markers of bone metabolism (alkaline phosphatase, type I collagen crosslinked-C-telopeptide) and 25OH vitamin D.


RESULTS
Based on Z-scores, bone mineral density was moderately reduced only at the femoral neck in the total cohort. The average Z-score of the "low PTH" group (iPTH < 100 pg/ml) was not different from the Z-score of patients with iPTH in the "target range" (100-300 pg/ml) at any measurement site. While iPTH was negatively correlated with BMD at all measurement sites in patients with iPTH > 100 pg/ml (rho = -0.255, -0.278 and -0.251 for LS, FN and DR, respectively, P < 0.001 for all), BMD was independent of iPTH in patients with iPTH < 100 pg/ml. Furthermore, iPTH was not associated with serum markers of bone metabolism, but these markers were negatively correlated with BMD in the "low PTH" group.


CONCLUSIONS
Low PTH levels are not associated with low BMD in patients with end-stage kidney disease. Furthermore, bone metabolism seems to be independent of iPTH in patients with relative hypoparathyroidism likely reflecting skeletal resistance to PTH.
Ambrus
Cs
C
1st Department of Internal Medicine, Semmelweis University, 2/a Koranyi S. u., 1083, Budapest, Hungary.
Almasi
Cs
C
Berta
K
K
Deak
Gy
G
Marton
A
A
Molnar
M Zs
MZ
Nemeth
Zs
Z
Horvath
Cs
C
Lakatos
P
P
Szathmari
M
M
Mucsi
I
I
D015502:Absorptiometry, Photon; D015519:Bone Density; D001851:Bone Diseases, Metabolic / Q000097:blood* / Q000453:epidemiology / Q000209:etiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006814:Hungary / Q000453:epidemiology; D015994:Incidence; D007676:Kidney Failure, Chronic / Q000097:blood / Q000150:complications / Q000628:therapy*; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood*; D006435:Renal Dialysis; D012307:Risk Factors
D010281:Parathyroid Hormone