RESUMO
PURPOSE: The purpose of this retrospective cohort study was to measure the difference between cholecalciferol and ergocalciferol in their ability to effect vitamin D, parathyroid hormone (PTH), calcium, and phosphorous serum concentrations in patients with stage 3 or 4 chronic kidney disease. METHODS: This was a retrospective cohort study conducted within a single-center ambulatory nephrology clinic. Patients eligible for the study were identified through medical records displaying each patient's initiation on either ergocalciferol or cholecalciferol from 2013 to 2016. Patients' baseline vitamin D, PTH, calcium, and phosphorous serum concentrations were taken prior to treatment initiation, and patients were reassessed with a second measurement within 12 months of therapy. RESULTS: Out of 149 eligible patients, 110 were excluded. There were 33 patients included on cholecalciferol and 6 patients on ergocalciferol. A significant difference was observed in the percent change of phosphorous serum concentrations from baseline following drug administration (p=0.03). The mean changes from baseline to final serum phosphorous concentrations (mg/dL) were 0.12 and -0.3 for cholecalciferol and ergocalciferol, respectively. There was no significant difference in vitamin D (14.9, 15.1, p=0.97), PTH (5.6, 2.3, p=0.72), or calcium (0.05, -0.17, p=0.08) serum concentrations between cholecalciferol and ergocalciferol, respectively. There was a statistically significant increase in the mean change in serum phosphorous concentrations within the cholecalciferol group compared to the ergocalciferol group. CONCLUSION: In this small pilot study, cholecalciferol treatment appeared to increase serum phosphorous concentrations compared to ergocalciferol. These observations may warrant further large-scale studies that are appropriately powered to validate such findings.