Relative hypoparathyroidism in hemodialysis patients

To clarify the incidence and contributing factors of hypoparathyroidism in a hemodialysis (HD) population, 224 patients undergoing maintenance HD were investigated. They were divided into 4 groups according to their high-sensitive parathyroid hormone levels: extra-high (EH) group > 420,000 pg/ml; high (H) group 20,000-420,000 pg/ml; moderate (M) group 4,500-20,000 pg/ml; low (L) group, < 4,500 pg/ml. In group L, a 25-mg/kg deferoxamine (DFO) infusion test was undertaken to estimate aluminum (Al) accumulation. The distribution in each group was 42, 35, 12, and 11% for groups L, M, H and EH, respectively. Group-L patients were relatively older than those of the other groups. Diabetes was seen in 20% of group-L patients, as opposed to no diabetes in groups H and EH. Among the 22 diabetics, 82% were in group L. 70% of group-L patients showed a less than 50-micrograms/l Al increment after the DFO infusion test. Bone mineral density (BMD) did not differ between the groups with relative hypoparathyroidism (RHP=L) and background-matched non-RHP, either at the initiation of HD or the recent period, and the changes in BMD were comparable between the 2 groups. These results suggest that a considerable number of HD patients show RHP. Diabetes, but not Al accumulation, was considered to be one of the predisposing factors of RHP. Though the outcome of RHP will be aplastic bone disease (ABD) in HD patients, the clinical significance of ABD has not been fully evaluated. Further studies are required to clarify the precise mechanisms of RHP and the significance of ABD.