Parathyroid hormone in a population of elderly patients on hemodialysis (preliminary data).

The parathyroid hormone (PTH) represents an important marker of parathyroid secretion and its increase expresses hyperparathyroidism. We studied 28 patients affected by chronic renal insufficiency who had been on hemodialysis for at least 5 years. Half of the patients were younger than 65 years (Group 1), and the remaining other 14 patients were older than 65 years (Group 2). The following laboratory parameters were determined in the blood samples: Ca, P, Mg, alkaline phosphatase (AP), whole molecule PTH (1-84). Mean PTH concentrations were 637.8 pg/ml in Group 1 and 147.6 pg/ml in Group 2, Students' t = 2.812, p = 0.009. No significant differences were observed in Ca, P, Mg and AP concentrations. The multiplicity of the factors involved make it difficult to interpret the diverse, anomalous parathyroid responses to the same clinico-metabolic situations. Nevertheless, a reduced response of the parathyroid gland in the older group to stimuli typical of uremia may be postulated.