Navigation

Supporting Evidence and Description of Evidence Grading

A consistent and defined process is used for literature search and review for the development and revision of ICSI guidelines. Literature search terms for the current version of this document include:
Lipids
LDL
HDL
Dyslipidemia
Hypercholesterolemia
Statins

I
ndividual research reports are assigned a letter indication the class of report based on design type:  
    A, B, C, D, M, R, X

Evidence citations are listed in the document utilizing this format:  (Author, YYYY [report class])

A full explanation of ICSI's Evidence Grading System can be found on the ICSI Web site

Evidence Grading Table

 Class     Description
 Primary Reports of New Data Collection
 A Randomized, controlled trial
 BCohort-study
 C Non-randomized trial with concurrent or historical controls
     Case-control study
     Study of sensitivity and specificity of a diagnostic test
     Population-based descriptive study
 DCross-sectional study
     Case series
     Case report 
 Reports that Synthesize or Reflect upon Collections of Primary Reports
 M Meta-analysis
     Systematic review
     Decision analysis
     Cost-effectiveness analysis
 R Consensus  statement
     Consensus report
     Narrative review
 XMedical opinion 


Conclusion Grades
Key conclusions (as determined by the work group) are supported by a conclusion grading worksheet that summarizes the important studies pertaining to the conclusion. Individual studies are classed according to the system defined above and are assigned a designator of +, -, or ø to reflect the study quality. Conclusion grades are determined by the work group based on the following definitions:

Grade I:  The conclusion is supported by good evidence. 

The evidence consists of results from studies of strong design for answering the question addressed. The results are both clinically important and consistent with minor exceptions at most. The results are free of any significant doubts about generalizability, bias, and flaws in research design. Studies with negative results have sufficiently large samples to have adequate statistical power. 


Grade II:  The evidence consists of results from studies of strong design for answering the question addressed, but there is some uncertainty attached to the conclusion because of inconsistencies among the results from the studies or because of minor doubts about generalizability, bias, research design flaws, or adequacy of sample size. Alternatively, the evidence consists solely of results from weaker designs for the question addressed, but the results have been confirmed in separate studies and are consistent with minor exceptions at most. 


Grade III:  The evidence consists of results from studies of strong design for answering the question addressed, but there is substantial uncertainty attached to the conclusion because of inconsistencies among the results from different studies or because of serious doubts about generalizability, bias, research design flaws, or adequacy of sample size.  Alternatively, the evidence consists solely of results from a limited number of studies of weak design for answering the question addressed.  


Grade Not Assignable:  There is no evidence available that directly supports or refutes the conclusion. 


The symbols +, , ø, and N/A found on the conclusion grading worksheets are used to designate the quality 

of the primary research reports and systematic reviews: 

+ indicates that the report or review has clearly addressed issues of inclusion/exclusion, bias, generaliz- 
ability, and data collection and analysis; 

indicates that these issues have not been adequately addressed; 

ø indicates that the report or review is neither exceptionally strong or exceptionally weak; 

N/A indicates that the report is not a primary reference or a systematic review and therefore the quality has 
not been assessed.