Lack of relation between secondary hyperparathyroidism and red blood cell osmotic fragility in chronic renal failure.

The possible relationship between red blood cell (RBC) osmotic fragility and secondary hyperparathyroidism (HPT) in chronic renal failure was examined in 23 uremic patients on conservative therapy and in 42 patients on maintenance hemodialysis. 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). This study showed increased RBC osmotic fragility in uremic patients when compared with controls, with no difference between those on conservative therapy and those on maintenance hemodialysis. No correlation between RBC osmotic fragility and the hematochemical changes associated with secondary HPT was found. No difference in RBC osmotic fragility was observed with regard to the activity (alkaline phosphatase) and the severity (X-ray findings) of secondary HPT. Effective treatment of secondary HPT by either pharmacological means (1,25-dihydroxycholecalciferol) or surgical removal was not associated with consequent improvement in RBC osmotic fragility. It is concluded that secondary HPT is probably not a major factor influencing RBC osmotic fragility in chronic renal failure.