Relationship between plasma levels of homocysteine and the related B vitamins in patients with hemodialysis adequacy or inadequacy

•Water-soluble vitamins (e.g., folate, vitamins B6 and B12) and homocysteine might be lost during hemodialysis (HD), but it is unclear whether the loss of these vitamins is associated with plasma homocysteine concentration before and after HD treatment, especially in well-dialyzed patients.•Plasma vitamin B12 rather than plasma folate and vitamin B6 was negatively associated with plasma homocysteine in HD patients before and after receiving HD treatment regardless of dose dialysis or taking B-vitamin supplementation.•This significant association of vitamin B12 and homocysteine seemed not to be attributed to insufficient intake or excessive loss in dialysate but could be due to impaired vitamin metabolism. Vitamin B12 seemed to be a significant factor in relation to plasma homocysteine concentration in HD patients.