Association of secondary hyperparathyroidism with red cell survival in chronic haemodialysis patients.

51Cr red cell mass (RCM), 51Cr red cell survival (RCS) and plasma parathyroid hormone (PTH) levels were measured in 27 stable chronic haemodialysis patients with a variable degree of clinical secondary hyperparathyroidism. Included were five patients who had had total parathyroidectomy. The results showed a strong negative correlation between PTH and RCS (r = -0.67, P less than 0.001) and a positive correlation between RCS and RCM (r = +0.53, P less than 0.005). However, the negative correlation between PTH and RCM was weak (r = -0.45, P less than 0.02). When the 13 patients with normal PTH levels (mean 0.18 +/- 0.12 microgram/l) were compared with the 14 patients with raised levels (mean 1.35 +/- 0.71 micrograms/l), there was a marked difference in RCS (P less than 0.005) but no difference in RCM.