No benefit of vitamin K in improving mortality or reducing calcification in dialysis patients: Study

The researchers found that vitamin K is a safe product in dialysis patients for improving vitamin K status, however, no clear benefit was seen in improving mortality or reducing vascular calcification. Vitamin K1 had a greater impact on reducing calcification biomarkers.

"Vitamin K had no significant impact on mortality in seven studies (out of 11 included studies)," they reported.

Previous studies have shown that dialysis and chronic kidney disease (CKD) patients with optimal vitamin K status have better survival than those with vitamin K deficiency. Adrian Covic, Nephrology, Dialysis, Transplantation, Spitalul Clinic Dr C I Parhon, Iasi, Romania, and colleagues aimed to evaluate the impact of vitamin K supplementation in dialysis patients by realizing a systematic review and metanalysis of randomized trials.

For this purpose, the researchers searched the electronic databases for clinical randomized trials among vitamin K-treated patients. Random effects models were conducted, risk of bias was conducted with Cochrane tools, and the search was done until September 15, 2023.

The research included eleven trials comprising 830 patients (both pediatric and adult, mainly hemodialysis) that compared vitamin K with different controls: lower doses of vitamin K, standard care or placebo.

The researchers reported the following findings:

• Vitamin K supplementation did not affect mortality.
• Vitamin K administration improved vitamin K levels and led to lower levels of dp-uc-MGP and moderately increased calcium levels [0.18].
• Vitamin K1 proved more potency in reducing dp-uc-MGP [SMD −1.64 versus −0.56] and raised serum vitamin K levels compared with vitamin K2 [5.69 versus 2.25].
• While it did not have a proven benefit in changing calcification scores [−0.14], vitamin K proved to be a safe product.
• There was some concern with bias.

The research showed that vitamin D supplementation did not affect mortality and had no significant benefit in reversing calcification scores. However, vitamin K1 improved vitamin K deposits and lowered dp-uc-MGP, which is a calcification biomarker more than vitamin K2.

"As it proved to be a safe product, there is a need for additional randomized well-powered studies with improved treatment regimens to establish the true impact of vitamin K in dialysis patients," the researchers concluded.

Limitations included the different treatment administration protocol and various phenotypes of included populations are both sources of the observed heterogeneity, limited sample sizes in all studies, and mortality was considered as the primary outcome that was not influenced by vitamin K administration.

Reference:

Andrian, T., Stefan, A., Nistor, I., & Covic, A. (2023). Vitamin K supplementation impact in dialysis patients: A systematic review and meta-analysis of randomized trials. Clinical Kidney Journal, 16(12), 2738-2749. https://doi.org/10.1093/ckj/sfad255