Vitamin K supplementation impact in dialysis patients: a systematic review and meta-analysis of randomized trials.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 38046003 · doi:10.1093/ckj/sfad255
What was done
Systematic review and meta-analysis of randomized clinical trials searched through September 15, 2023, assessing vitamin K supplementation versus lower doses, standard care, or placebo in dialysis patients (both adult and pediatric, primarily hemodialysis). Risk of bias was evaluated using Cochrane tools, and random-effects models were applied for pooling outcomes.
What was found
Across 11 trials encompassing 830 patients, vitamin K had no effect on mortality and did not significantly alter calcification scores (SMD -0.14 [95% CI -0.37 to 0.09]). Vitamin K supplementation lowered dp-uc-MGP levels, with vitamin K1 showing greater reduction than vitamin K2 (SMD -1.64 [95% CI -2.05 to -1.23] vs. -0.56 [95% CI -0.82 to -0.31]), and raised serum vitamin K levels more than vitamin K2 (5.69 [95% CI 3.43 to 7.94] vs. 2.25 [95% CI -2.36 to 6.87]). It also moderately increased calcium levels (0.18 [95% CI 0.04 to 0.32]). The intervention was reported to be safe.
Why it matters
Although vitamin K supplementation effectively corrects biochemical markers associated with vascular calcification risk, evidence from randomized trials to date does not show improvement in vascular calcification scores or survival in dialysis patients.
Limits
The total sample size across all 11 trials is modest (830 patients), with heterogeneous patient populations (adults and pediatrics), varied comparators, and varied formulations/doses. The primary trials carried some risk of bias and were not adequately powered for hard clinical endpoints.
Cited by
- contradicts Vitamin K2 prevents calcium from depositing in soft tissues.