Folic acid supplementation with and without vitamin B6 and revascularization risk: a meta-analysis of randomized controlled trials.
OBJECTIVE
There is a growing amount of data and a continuing controversy over the effect of folic acid supplementation with and without vitamin B6 on revascularization risk.


METHODS
We conducted a meta-analysis based on up-to-date published relevant randomized trials to further examine this issue. Relative risk (RR) was used to measure the effect of folic acid supplementation on risk of revascularization using a random-effects model. Total revascularization was defined as any arterial revascularization. Restenosis was defined as stenosis of more than 50 percent of the luminal diameter.


RESULTS
Overall, folic acid supplementation had no significant effect on coronary revascularization (9 trials, n = 27,418, RR = 0.99; 95%CI:0.88-1.11, P = 0.88), coronary artery bypass grafting (CABG) (5 trials, n = 10,703, 0.90; 0.79-1.03, P = 0.11), percutaneous coronary intervention (PCI) (5 trials, n = 10,703, 1.05; 0.89-1.23, P = 0.59), coronary restenosis (3 trials, n = 926, 1.05; 0.89-1.23, P = 0.59) or total revascularization (7 trials, n = 29,314, 1.06; 95%CI: 0.99-1.13, P = 0.10). However, a greater beneficial effect was observed for coronary revascularization among those trials with a moderate dose of vitamin B6 (5-10 mg/d; RR: 0.47; 95%CI: 0.28-0.80, P = 0.005), but not in trials without vitamin B6 or with a high dose of vitamin B6. And a non-significant greater total revascularization risk was observed in trials with a higher folic acid dose (>2 mg/d, RR = 1.11; 95%CI: 0.98-1.25, P = 0.09; ≥5 mg/d, RR = 1.98; 95%CI: 0.93-4.20, P = 0.08).


CONCLUSIONS
Our analyses indicate that folic acid supplementation has no significant effect on coronary revascularization, CABG, PCI, coronary restenosis or total revascularization. However, a combination of folic acid and moderate vitamin B6 may be beneficial in reducing coronary revascularization risk.
Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China; Institute of Biomedicine, Anhui Medical University, Hefei, China.
Xianhui
X
Qin
Department of Cardiology, Peking University First Hospital, Beijing, China.
Fangfang
F
Fan
Department of Pharmacy, Peking University First Hospital, Beijing, China.
Yimin
Y
Cui
Department of Cardiology, Capital Medical University Affiliated with Beijing Anzhen Hospital, Beijing, China.
Fang
F
Chen
Department of Cardiology, People's Liberation Army General Hospital, Beijing, China.
Yundai
Y
Chen
Department of Cardiology, Second Affiliated Hospital, Nanchang University, Nanchang, China.
Xiaoshu
X
Cheng
Institute of Cardiovascular Disease and Heart Center, Pinjing Hospital Logistics University of the Chinese People's Armed Police Forces, Tianjin, China.
Yuming
Y
Li
Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
Binyan
B
Wang
Guangdong Institute of Nephrology, Southern Medical University, Guangzhou, China.
Xin
X
Xu
Guangdong Institute of Nephrology, Southern Medical University, Guangzhou, China.
Xiping
X
Xu
Department of Cardiology, Peking University First Hospital, Beijing, China. Electronic address: huoyong@263.net.cn.
Yong
Y
Huo
Center on the Early Life Origins of Disease, Department of Population, Family and Reproductive Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA. Electronic address: xiwang@jhsph.edu.
Xiaobin
X
Wang
D001026:Coronary Artery Bypass / Q000379:methods; D023903:Coronary Restenosis / Q000517:prevention & control*; D016208:Databases, Factual; D019587:Dietary Supplements; D005492:Folic Acid / Q000008:administration & dosage*; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D025101:Vitamin B 6 / Q000008:administration & dosage*
D025101:Vitamin B 6; D005492:Folic Acid
Folic acid supplementation; Meta-analysis; Randomized controlled trials; Revascularization risk