Vitamin D supplementation of no substantial benefit in patients with type 2 diabetes and CKD

The findings, published in American Heart Journal, do not support routine active vitamin-D use for cardiovascular protection and LVMI regression in patients with T2D and stage-3 chronic kidney disease.

About 30-40% of type 2 diabetes patients suffer from CKD stage-3 (eGFR 30-59ml/min). CVD (cardiovascular disease) is the leading cause of death in patients with CKD stage-3 and type 2 diabetes. In patients with CKD, an increase in left ventricular mass and left ventricular hypertrophy (LVH) are recognized as independent predictors of heart failure, mortality, and CVD. CKD and T2D are independently linked with increased LVMI and diastolic dysfunction with early modification of left ventricular structure and function.

Evidence suggests that vitamin D has pleiotropic effects besides its well-known action on calcium, phosphate and bone metabolism. Some studies have shown that active vitamin D deficiency is a potentially modifiable risk factor for increased ventricular mass. Considering this, Luigi Gnudi, Guy's and St Thomas Hospital. London, UK, and colleagues investigated the effects of active vitamin-D (calcitriol) treatment on left ventricular mass in patients with type-2 diabetes and chronic kidney disease.

For this purpose, the investigators performed a 48-week duration single centre randomized, double-blind parallel-group trial examining the impact of 0.5 mcg once daily calcitriol compared to placebo on a primary endpoint of change from baseline LVMI measured by MRI (magnetic resonance imaging).

Patients with CKD stage-3, T2D, and raised left ventricular mass on stable renin angiotensin aldosterone system blockade having elevated parathyroid hormone (iPTH) were included. Secondary endpoints were interstitial myocardial fibrosis examined through cardiac MRI. 45 patients (73% males) with T2D and stage-3 CKD were studied (placebo n=26, calcitriol n=19).

The study revealed the following findings:

• Following 48 weeks of calcitriol treatment, the median difference and the LVMI between the two treatment arms was 1.84, similar to the two groups studied.
• iPTH fell only in the calcitriol group from 142 pg/ml to 76 pg/ml.
• No significant differences were observed in interstitial myocardial fibrosis or other secondary endpoints.

"Our study does not provide evidence that calcitriol treatment compared to a placebo might improve LVMI or other biomarkers of cardio-renal risk in patients with type 2 diabetes, stable CKD, and mild LVH, following 48-week treatment with calcitriol or placebo," the researchers wrote.

"Our data does not support the routine active vitamin-D use for LVH regression and cardiovascular protection in patients with T2D and stage-3 CKD," they conclude.

Reference:

Gnudi, L., Fountoulakis, N., Panagiotou, A., Corcillo, A., Maltese, G., Rife, M. F., Ntalas, I., Franks, R., Chiribiri, A., Ayis, S., & Karalliedde, J. (2023). Effect of active vitamin-D on left ventricular mass index: Results of a randomized controlled trial in type 2 diabetes and chronic kidney disease. American Heart Journal. https://doi.org/10.1016/j.ahj.2023.03.003