Bone mineral density and bone metabolism in hemodialysis patients. Correlation with PTH, 25OHD3 and leptin.

BACKGROUND Bone metabolism disorders in hemodialysed patients (HD) involve several humoral factors, of which PTH plays the central role. Leptin is usually found increased in renal failure and its link with bone metabolism has not been elucidated. We investigated the BMD and bone metabolism in association with serum PTH, 25OHD3 and leptin in HD patients. METHODS We measured bone alkaline phosphatase (bSAP), cross linked N telopeptide of type 1 collagen (NTx), PTH, 25OHD3 and leptin in 37 HD patients. We also evaluated BMI and BMD in lumbar spine (LS) and in femoral neck (FN) by DXA. Statistical evaluations were based on simple regression analysis. RESULTS 1) Osteopenia was found in 32,1% in LS and 50% in FN and osteoporosis in 14.3% and 21.4% of our patients, respectively. LS or FN Z score was not related to HD duration. 2) Bone markers, PTH, phosphorus and leptin levels were increased. 3) 25OHD3 was low and was not related to NTx, bSAP or PTH. 4) PTH correlated with bone markers and Z score in LS and FN. 5) Leptin had no correlation with bone markers or Z score (except BMI). CONCLUSIONS In our hemodialysed patients bone metabolism markers were increased in relation with high serum PTH levels. The observed high serum leptin was not associated with bone metabolism. Additionally the duration of hemodialysis did not appear to affect bone density.