Endocrine Abstracts

Secondary hyperparathyroidism (SHPT) is common in patients with chronic kidney disease (CKD). The aim of the study was to analyze dynamics of PTH secretion during 1 year of observation of patients with CKD stage 3 and 4. We examined 40 patients, 22 f, 18 m; age 55.9±14.5 years. Mean glomerular filtration rate (GFR)? Calculated by MDRD formula was 27.2±15.7 ml/min; 15 patients have CKD stage 3, 25 – stage 4. Serum PTH, 25(OH)D3, calcium (Ca) and phosphorus (P) were measured initially and at the end of observation period (mean 12.4±1.6 months). Initially SHPT as well as vitamin D deficiency were revealed in 80% of cases. 90% of patients with vitamin D deficiency had SHPT. We found significant negative correlation of PTH level and eGFR (r=−0.55), vitamin D level (r=−0.34). 20 patients with vitamin D deficiency (25(OH)D3 <20 ng/ml) were recommended to receive vitamin D supplements, 2000 IU daily. After 1 year PTH increased in 45% of patients, mean increase was 65.4 pg/ml (95%CI 27.5 – 103.3). Subgroup with increased PTH shown higher initial PTH level (P=0.003) and lower eGFR (P=0.0008). At the end of observation we did not found significant changes of PTH level both in patients received vitamin D and not received supplements. PTH was 168.5±132.1 initially and 164.7±1.6 pg/ml at the end of observation, P=0.578. GFR significantly declined from 27.2±15.7 to 21.3±1.8 ml/min (P=0.0004). At the same time in patients received vitamin D supplements vitamin D level increased from 11.6±5.0 to 31.1±12.3 ng/ml, P=0.0002, Ca and P levels remained unchanged. In the subgroup of patients not supplemented with vitamin D serum Ca decrease from 2.46±0.19 to 2.35±0.15 mmol/l. We can assume that in patients with CKD stages 3 and 4 frequency of both SHPT and vitamin D deficiency is high (80%). Supplementation of vitamin D 2000 IU daily allows restoring normal vitamin D level but seems to not have significant effect on PTH, at list on its decrease. 45% of patients demonstrate PTH increase after 1 year of observation, most predictive value have initial higher level of PTH and lower GFR. Further study is required to confirm this findings and to choose the best strategy of follow-up for patients with SHPT.