Endocrine Abstracts

The aim was to analyse dynamics of PTH secretion in dialysis patients during different period of observation and to determine factors of secondary hyperparathyroidism progression. We examined 92 patients, 52f, 40m; age 47.2±11.4 years; dialysis duration 4.9±3.9 years; mean observational period 8.9±4.3 months (6–24). Serum PTH, 25(OH)D3, osteocalcin (OC), C-terminal telopeptide of type I collagen (β-CTx), alkaline phosphotase (ALP), calcium (Ca), and phosphorus (P) were measured initially and at the end of observation. All patients were recommended to follow low-phosphate diet and 74.4% received calcium carbonate. PTH level was 559.6±552.5 initially and 603.9±581.6 pg/ml at the end of observation, P=0.251. Frequency of high, normal uremic and low PTH levels was 55.4% vs 57.6%, 20.7% vs 21.7% and 23.9% vs 20.7% respectively (P>0.05). P decreased from 2.34±0.67 to 2.14±0.60 mmol/l, P=0.0003. In patients with initial hypercalcaemia PTH increased from 525.3±518.4 to 616.2±606.2 pg/ml, P=0.03. PTH level at the end of observation correlate with age (r=−0.25), OC (r=0.58), β-CTx (r=0.76), and ALP (r=0.40). Strong correlation was found with the initial PTH (r=0.84). At the end of observation PTH decreased in 40 patients (43.5%), mean decrease 204.6±250.1 pg/ml; increased in 52 patients (56.5%), mean increase 235.6±274.5 pg/ml. Subgroups with decreased and increased PTH didn’t show differences of demographic data, levels of Ca, P, and bone turnover markers. Comparison of initial and repeated PTH level in subgroups with duration of observation 6, 9, 12, and >12 months didn’t reveal significant changes. We can assume that in dialysis patients with stable parameters of Ca, P, and bone turnover markers in the absence of therapeutic intervention of secondary hyperparathyroidism PTH level remains unchanged during period of observation up to 12 months and even more. In such patients reasonable interval of PTH measurement should be 6–12 months. Initial level of PTH is the most important predictor of parathyroid function dynamics. Young age, high Ca, P, and bone turnover markers levels are another factors influencing secondary hyperparathyroidism progression.