Bone mineral disturbances in patients with chronic kidney disease stage 5 not yet on dialysis

Aims: This retrospective study evaluates the success of a treatment strategy for secondary hyperparathyroidism in our cohort of patients with chronic kidney disease stage 5 who were not yet on dialysis. Materials and methods: 81 predialysis patients from the outpatient clinic of the Department of Nephrology, University Medical Center Ljubljana were reviewed. We focused on serum markers for bone mineral metabolism including intact parathyroid hormone (PTH), phosphate, corrected calcium, and the usage of phosphate-binding agents and vitamin D analogs. Results of intact PTH and phosphorus and calcium concentrations were related to treatment options for secondary hyperparathyroidism. Results: The average intact PTH concentration was 198.8 +/- 162.5 ng/L, serum phosphate was 1.52 +/- 0.35 mmol/L, and corrected calcium was 2.23 +/- 0.2 mmol/L. Phosphate-binding agents were prescribed in 62% patients, 44% of these patients were on calcium-containing phosphate binders. Active vitamin D or synthetic vitamin D analogs were given to 65% of patients, and 48% of all received a combination of active vitamin D derivate and inactive vitamin D supplementation. Serum intact PTH was between 150 and 300 ng/L in 30%, under 150 ng/L in 46%, and over 300 ng/L in 24% of patients, respectively. Conclusions: Our data show that 76% of our patients with CKD stage 5 not yet on dialysis achieved adequate control of secondary hyperparathyroidism. Marked reduction of intact PTH levels in a significant proportion of our patients prompt us to assess the administration of excessive amounts of calcium and/or vitamin D supplements to prevent over-suppression of PTH, which can induce adynamic bone disease.