EAL

DLM: Homocysteine, Folate, B6 or B12 (2007-2011)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To report the results of a quantitative systematic review of cohort studies that evaluate the association between plasma Hcyt and incidence of a first cardiovascular event.

Inclusion Criteria:

MEDLINE database search with keywords: “homocysteine” and “athlerosclerosis” filtered for human subjects

--looked at cohort and nested case-control studies that identified plasma Hcyt as exposure and first cardiovascular event as outcome

--checked references for additional eligible publications

Exclusion Criteria:

case-control excepted nested (nested are free from reverse causality bias and comparability of cases and controls is guaranteed)

Description of Study Protocol:

--study outcomes: first cardiac events (fatal and non-fatal MI, death from cardiovascular causes, unstable angina, subsequent coronary artery bypass surgery, first CVA

Data Collection Summary:

Description of Actual Data Sample:

--14 cohort studies

--data from 2529 cases and 7305 non-cases

Summary of Results:

--increments in plasma total Hcyt concentration results in significant increase in risk of cardiovascular disease (ARR=1.33, 95% CI: 1.21-1.47); p=0.004

--increase in coronary heart disease (ARR=1.49, 95% CI: 1.31-1.70); p=0.006

--increase in stroke (ARR=1.37, 95% CI: 0.99-1.91); p=0.328

--magnitude of average RR (ARR) not affected by age (p=0.83)

--duration of study follow-up did not affect results (p=0.25)

Author Conclusion:

--hyperhomocysteinemia moderately increases risk for first CVD event

--is Hcyt the best marker to measure risk? Perhaps Hcyt-thiolactone is better

Funding Source:

University/Hospital:

Universidad Industrial de Santander (Columbia), Fundation Cardiovascular del Oriente Colombiano (Columbia)

Reviewer Comments:

Quality Criteria Checklist: Review Articles
Relevance Questions
	1.	Will the answer if true, have a direct bearing on the health of patients?	Yes
	2.	Is the outcome or topic something that patients/clients/population groups would care about?	Yes
	3.	Is the problem addressed in the review one that is relevant to dietetics practice?	Yes
	4.	Will the information, if true, require a change in practice?	Yes

Validity Questions
	1.	Was the question for the review clearly focused and appropriate?	Yes
	2.	Was the search strategy used to locate relevant studies comprehensive? Were the databases searched and the search termsused described?	Yes
	3.	Were explicit methods used to select studies to include in the review? Were inclusion/exclusion criteria specified andappropriate? Wereselectionmethods unbiased?	Yes
	4.	Was there an appraisal of the quality and validity of studies included in the review? Were appraisal methodsspecified,appropriate, andreproducible?	Yes
	5.	Were specific treatments/interventions/exposures described? Were treatments similar enough to be combined?	Yes
	6.	Was the outcome of interest clearly indicated? Were other potential harms and benefits considered?	Yes
	7.	Were processes for data abstraction, synthesis, and analysis described? Were they applied consistently acrossstudies and groups? Was thereappropriate use of qualitative and/or quantitative synthesis? Was variation in findings among studies analyzed? Were heterogeneity issued considered? If data from studies were aggregated for meta-analysis, was the procedure described?	Yes
	8.	Are the results clearly presented in narrative and/or quantitative terms? If summary statistics are used, are levels ofsignificance and/or confidence intervals included?	Yes
	9.	Are conclusions supported by results with biases and limitations taken into consideration? Are limitations ofthe review identified anddiscussed?	Yes
	10.	Was bias due to the review's funding or sponsorship unlikely?	???