Table 2.

Recently published randomized controlled trials of nutritional vitamin D supplementation in CKD

Study (Reference)	Study Type	Sample Size	Control Group	Randomized	Results	Limitations
Chandra et al. (67)	Double-blind, placebo-controlled, randomized controlled pilot study	20	Yes	Yes	Among cholecalciferol-treated participants, serum 25(OH)D concentration increased on average from 17.3 ng/ml (95% CI, 11.8–25.2) at baseline to 49.4 ng/ml (95% CI, 33.9–-72.0) at week 12. As-treated analysis indicated a trend toward lower PTH levels among cholecalciferol-treated participants (P=0.07)	Small study
						Short follow-up period
Dogan et al. (66)	Randomized	40	Yes	Yes	Administration of depot oral cholecalciferol (300,000 IU vitamin D3) resulted in a significant increase in calcidiol (6.8±3.5 to 17.8±21.4 ng/ml, P<0.001), significant decrease in iPTH (368±274 to 279±179 pg/ml, P<0.001). No statistically significant change in Ca, P, Ca × P, and urinary calcium creatinine rate was observed	Small study
						Short follow-up period
						Methodology does not specify whether investigators were blinded to the intervention
Oksa et al. (68)	Randomized	87	No	Yes	Vitamin D insufficiency/deficiency in CKD significantly improved after the 12-mo cholecalciferol treatment, with more significant improvement with higher dose (20,000 IU/wk) being more effective and equally safe	Lack of a placebo control
						The inclusion of a subgroup of patients who received calcium carbonate for correction of metabolic acidosis is a potential confounder
Kovesdy et al. (17)	Randomized, not blinded	80	Active	Randomized	80 CKD patients randomized to ergocalciferol versus paricalcitol. Paricalcitol group showed lower PTH levels than ergocalciferol group	Not blinded
						Differential initiation of phosphate binders in the two groups

95% CI, confidence interval; PTH, parathyroid hormone.