Osmotic fragility of erythrocytes, cell deformability and secondary hyperparathyroidism in uremic patients on maintenance hemodialysis.

The possible relationship between erythrocyte (RBC) function and secondary hyperparathyroidism (HPT) was examined in 35 uremic patients on maintenance hemodialysis. Mechanical tests (i.e., osmotic fragility and deformability) were used to assess RBC function. Secondary HPT was evaluated by means of serum biochemistry (parathyroid hormone, calcium, phosphorus, and alkaline phosphatase) and radiographic examinations (X-ray films of the hand skeleton). Sixteen sex and age-matched normal volunteers acted as controls. This study shows that the mechanical properties of RBC were indeed markedly altered in hemodialysis patients when compared with controls. No significant correlations between either the osmotic fragility or the deformability of RBC and the hematochemical changes associated with secondary HPT were found. No differences in RBC function tests were found as far as the activity (alkaline phosphatase) or the severity (X-ray findings) of secondary HPT are concerned. Effective treatment of secondary HPT by either pharmacological means (1,25-dihydroxycholecalciferol) or surgical removal was not associated with consequent improvement in RBC function. These findings clearly speak against secondary HPT as a major cause of RBC dysfunction in uremic patients on maintenance hemodialysis.