Alfacalcidol vs. Calcitriol in the Management of Secondary Hyperparathyroidism in CKD

Background: This study aims to assess the efficacy of alfacalcidol compared to calcitriol in reducing iPTH levels in patients with chronic kidney disease Methods: This retrospective cohort study was conducted at our quaternary care hospital between January 1st, 2022, and December 31st, 2022. Adult Patients diagnosed with CKD stage 3 to 5 (not on dialysis) who received alfacalcidol for at least 3 months followed by calcitriol for another 3 months were included. Laboratory values were assessed at baseline, at 3 months while on alfacalcidol then at 3 months while on calcitriol. The primary outcome was the suppression of the iPTH , while the secondary outcome was the effect on total serum calcium. The study was approved by the hospital’s research ethics committee Results: Seventy adult patients were included in the analysis. Statistical analysis was conducted using Wilcoxon signed rank test and McNemer test. CKD stage 3 comprised 47.1% of the sample while stage 4 comprised 37.1%. The median dose of alfacalcidol was 0.5 (0.25-0.8) mcg, compared to 0.5 (0.25-0.5) mcg for calcitriol (p= 0.001). The median time between baseline and outcome laboratory measurements was 94 (83-106) days for alfacalcidol and 94 (78.5-110.5) for calcitriol (p= 0.676). No significant differences were observed in the use of phosphate binders or non-active vitamin D between the time periods. Alfacalcidol did not significantly suppress the iPTH levels with median values of 13.31 (8.23 - 24.4) pg/mL at baseline and 12.5 (8.86 - 24.7) pg/mL after 3 months (p= 0.937). In contrast, calcitriol significantly reduced the iPTH levels from 12.5 (8.86 - 24.7) pg/mL to 10.7 (5.7 -19) pg/mL (p= 0.017). Additionally, alfacalcidol did not significantly increase calcium levels, with values of 2.29 (2.2 - 2.3) mmol/L at baseline and 2.3 (2.23 - 2.36) mmol/L after 3 months (p=0.237), whereas calcitriol significantly increased calcium levels from 2.3 (2.23 - 2.36) mmol/L to 2.34 (2.27 - 2.43) mmol/L (p=0.001). Albumin values remained unchanged throughout the study period Conclusion: Calcitriol, at significantly lower doses, was more effective than alfacalcidol in reducing iPTH levels and increasing calcium levels over 3 months. Larger prospective controlled studies are needed to confirm these findings