Homocysteine‐lowering interventions (vitamins B6 (pyridoxine; pyridoxal); B9 (folic acid) or B12 (cyanocobalamin) compared with placebo or standard care for preventing cardiovascular events |
Patient or population: adults at risk of or with established cardiovascular disease
Settings: outpatients
Intervention: homocysteine‐lowering interventions (vitamins B6 (pyridoxine; pyridoxal), B9 (folic acid) or B12 (cyanocobalamin).
Comparison: placebo or standard care |
Outcomes |
Illustrative comparative risks* (95% CI) |
Relative effect
(95% CI) |
No of Participants
(studies) |
Quality of the evidence
(GRADE) |
Comments |
Assumed risk |
Corresponding risk |
Placebo or standard care |
Homocysteine‐lowering interventions
(vitamins B6 (pyridoxine; pyridoxal); B9 (folic acid) or B12 (cyanocobalamin)
|
Myocardial infarction
Follow‐up: 1 to 7.3 years |
60 per 1000 |
61 per 1000
(57 to 66) |
RR 1.02
(0.95 to 1.10) |
46,699
(12 trials) |
⊕⊕⊕⊕
high
|
|
Stroke
Follow‐up: 1 to 7.3 years |
51 per 1000 |
46 per 1000
(42 to 50) |
RR 0.90
(0.82 to 0.99) |
44,224
(10 trials) |
⊕⊕⊕⊕
high
|
|
Death by any cause
Follow‐up: 1 to 7.3 years |
123 per 1000 |
124 per 1000
(118 to 130) |
RR 1.01
(0.96 to 1.06) |
44,817
(11 trials) |
⊕⊕⊕⊕
high
|
|
Adverse events
Follow‐up: 3.4 to 7.3 years |
85 per 1000 |
91 per 1000
(85 to 97) |
RR 1.07
(1.00 to 1.14) |
35,788
(8 trials) |
⊕⊕⊕⊕
high
|
Cancer is the only reported adverse event. |
*The basis for the assumed risk (e.g. the median control group risk across studies) is the outcomes of the study control arms. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
CI: Confidence interval; RR: Risk ratio; |
GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate. |