title: Effects of paricalcitol on urinary calcium in patients with chronic kidney disease stages 2 - 4.
abstract: OBJECTIVE
  Secondary hyperparathyroidism is an early complication of chronic kidney disease (CKD), with increasing severity as the glomerular filtration rate decreases. Treatment with calcitriol can occasionally result in hypercalcemia and hyperphosphatemia in renal patients, but next generation vitamin-D analogs such as paricalcitol have lower intestinal absorption of calcium and phosphorous. Our aim was to assess whether paricalcitol is more beneficial than calcitriol in pre-dialysis CKD patients in clinical practice.
  
  
  METHODS
  This observational study was carried out in a clinical setting. A total of 220 patients diagnosed with CKD stages 2 - 4, who had been previously treated with calcitriol (0.25 μg/48 hours) for 6 months, were screened. 45 patients presenting total calcium > 9.5 mg/dL or serum phosphate > 4.5 mg/dL and who did not meet exclusion criteria werefinally selected, and their calcitriol treatment was switched to paricalcitol. Baseline blood and urine analyses were performed before switching treatment, and then repeated after 6-month treatment with paricalcitol (1 μg/45 h). Baseline and follow-up data were compared.
  
  
  RESULTS
  No significant changes were detected in the total serum calcium, ionized calcium, serum phosphate, tubular reabsorption of phosphate, urinary phosphate, or parathyroid hormone. There was a slight decrease in plasma calcitriol levels after switching to paricalcitol. Only urinary calcium levels showed a significant decrease: 58.1 ± 7.4 mg/24 hours during calcitriol treatment and 48.9 ± 6.1 mg/24 hours after 6 months with paricalcitol (p = 0.04).
  
  
  CONCLUSIONS
  Compared to calcitriol, paricalcitol decreases urinary calcium excretion in pre-dialysis CKD patients, suggesting that paricalcitol treatment for secondary hyperparathyroidism might result in less systemic calcium overload.
authors.forename: Isabel
authors.initials: I
authors.lastname: Martinez-Fernandez
authors.forename: Ramón
authors.initials: R
authors.lastname: Saracho
mesh_terms: D000368:Aged; D002113:Calcification, Physiologic; D002118:Calcium / Q000652:urine*; D004872:Ergocalciferols / Q000494:pharmacology*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007684:Kidney Tubules / Q000378:metabolism; D008297:Male; D011446:Prospective Studies; D051436:Renal Insufficiency, Chronic / Q000188:drug therapy* / Q000503:physiopathology / Q000652:urine
chemical_list: D004872:Ergocalciferols; C084656:paricalcitol; D002118:Calcium