For patients with diabetes, diabetic kidney disease is a major cause of end-stage kidney disease (ESKD) and cardiovascular disease. Previous, small studies have indicated that vitamin B may possibly help delay diabetic kidney disease progression via inhibition of vascular inflammation and endothelial cell damage. A recent study published in the Cochrane Library examines the benefits and harms of vitamin B therapy in patients with diabetic kidney disease.

The authors included nine clinical trials involving 1354 patients in their analysis; vitamin B and its derivatives alone [benfotiamine, folic acid, thiamine, or vitamin B12 monotherapy] or in combination [folic acid, vitamin B6, and vitamin B12]) were evaluated versus placebo, or active control (calcium channel blockers, ACEIs, ARBs). Duration of treatment ranged from 2–36 months. 

Only one study showed a decrease in albuminuria following thiamine use compared to placebo; none of the other studies showed a reduction in urinary albumin excretion with vitamin B monotherapy. In one other study, patients taking combination therapy were reported to have a reduction in glomerular filtration rate (GFR). As for improving kidney function, none of the vitamin B derivatives (monotherapy or combination therapy) had any significant impact on creatinine clearance, serum creatinine, or dialysis risk. Compared to placebo or active control, neither the vitamin B monotherapy or combination therapy was effective in significantly controlling blood pressure. With regards to all-cause mortality, there was no significant difference in risk with any dose or duration of pyridoxamine or combination therapy versus placebo. None of the included studies provided information on progression from microalbuminuria to macroalbuminuria or macroalbuminuria to ESKD.

The authors conclude that very little evidence exists to recommend vitamin B monotherapy or combination therapy for delaying diabetic kidney disease progression. While thiamine was shown to be beneficial in one study, due to the small size and low quality of the studies in this investigation, further research is needed to confirm the efficacy of vitamin B therapy in diabetic kidney disease.