In this third up date of the Cochrane review , there were no differences in effects of homocysteine-lowering interventions in the form of supplements of vitamins B6 , B9 or B12 given alone or in combination comparing with placebo on myocardial infa rct ion , death from any cause or adverse events .
BACKGROUND Cardiovascular disease , which includes coronary artery disease , stroke and peripheral vascular disease , is a leading cause of death worldwide .
Homocysteine is an amino acid with biological functions in methionine metabolism .
A postulated risk factor for cardiovascular disease is an elevated circulating total homocysteine level .
The impact of homocysteine-lowering interventions , given to patients in the form of vitamins B6 , B9 or B12 supplements , on cardiovascular events has been investigated .
This is an up date of a review previously published in 2009 , 2013 , and 2015 .
OBJECTIVES To determine whether homocysteine-lowering interventions , provided to patients with and without pre-existing cardiovascular disease are effective in preventing cardiovascular events , as well as reducing all-cause mortality , and to evaluate their safety .
GRADE guidelines: 4. Rating the quality of evidence--study limitations (risk of bias).
In the GRADE approach , r and omized trials start as high- quality evidence and observational studies as low- quality evidence , but both can be rated down if most of the relevant evidence comes from studies that suffer from a high risk of bias . Well-established limitations of r and omized trials include failure to conceal allocation , failure to blind , loss to follow-up , and failure to appropriately consider the intention-to-treat principle . More recently recognized limitations include stopping early for apparent benefit and selective reporting of outcomes according to the results . Key limitations of observational studies include use of inappropriate controls and failure to adequately adjust for prognostic imbalance . Risk of bias may vary across outcomes ( e.g. , loss to follow-up may be far less for all-cause mortality than for quality of life ) , a consideration that many systematic review s ignore . In deciding whether to rate down for risk of bias -- whether for r and omized trials or observational studies -- authors should not take an approach that averages across studies . Rather , for any individual outcome , when there are some studies with a high risk , and some with a low risk of bias , they should consider including only the studies with a lower risk of bias
In this third up date of the Cochrane review , there were no differences in effects of homocysteine-lowering interventions in the form of supplements of vitamins B6 , B9 or B12 given alone or in combination comparing with placebo on myocardial infa rct ion , death from any cause or adverse events .
BACKGROUND Cardiovascular disease , which includes coronary artery disease , stroke and peripheral vascular disease , is a leading cause of death worldwide .
Homocysteine is an amino acid with biological functions in methionine metabolism .
A postulated risk factor for cardiovascular disease is an elevated circulating total homocysteine level .
The impact of homocysteine-lowering interventions , given to patients in the form of vitamins B6 , B9 or B12 supplements , on cardiovascular events has been investigated .
This is an up date of a review previously published in 2009 , 2013 , and 2015 .
OBJECTIVES To determine whether homocysteine-lowering interventions , provided to patients with and without pre-existing cardiovascular disease are effective in preventing cardiovascular events , as well as reducing all-cause mortality , and to evaluate their safety .