Effect of calcitriol treatment on arterial stiffness in people with type 2 diabetes and stage 3 chronic kidney disease

Aims Active vitamin D deficiency is associated with increased aortic-pulse wave velocity (Ao-PWV) in people with type 2 diabetes (T2DM) and chronic kidney disease (CKD). There are no randomised controlled trials investigating the effect of active vitamin D treatment on Ao-PWV in people with T2DM and CKD. Methods A 48-week duration single-centre randomised double-blind parallel-group trial examined the impact of oral 1,25 dihydroxyvitamin D (calcitriol 0.25 mcg OD) as compared to placebo on a primary endpoint of Ao-PWV. People with T2DM and stable stage 3 CKD with intact parathyroid hormone (iPTH) level >30 pg/mL were eligible. Results In total, 127 (70% male) people were randomised (calcitriol n = 64 or placebo n = 63). There was no change in Ao-PWV observed, mean +/- standard deviation (SD), in the calcitriol group of 11.79 (+/- 2.5) to 12.08 (3.0) m/s as compared to 10.90 (+/- 2.4) to 11.39 (+/- 2.6) m/s with placebo. The between-treatment group adjusted mean (95% confidence interval [(CI]] change was 0.23 (-0.58 to 1.05) m/s, P = .57. No effect of calcitriol was observed on central arterial pressures, albuminuria, serum calcium or phosphate levels. However, iPTH fell with calcitriol treatment (mean [95% CI] between-group difference of -27.8 (-42.3 to -13.2) pg/mL, P < .001. Conclusion In T2DM and stage 3 CKD, calcitriol as compared to placebo does not improve Ao-PWV or other markers of arterial stiffness. Our study does not provide evidence for the use of active vitamin D for improving arterial stiffness in T2DM with stage 3 CKD.