Dietary Considerations for Cardiovascular Disease Risk Reduction

The references listed below are used in this DynaMed topic primarily to support background information and for guidance where evidence summaries are not felt to be necessary. Most references are incorporated within the text along with the evidence summaries.

1. Van Horn L, Carson JA, Appel LJ, et al; American Heart Association Nutrition Committee of the Council on Lifestyle and Cardiometabolic Health, Council on Cardiovascular Disease in the Young, Council on Cardiovascular and Stroke Nursing, Council on Clinical Cardiology, and Stroke Council. Recommended Dietary Pattern to Achieve Adherence to the American Heart Association/American College of Cardiology Guidelines: A Scientific Statement From the American Heart Association. Circulation. 2016 Nov 29;134(22):e505-e529, correction can be found in Circulation 2016 Nov 29;134(22):e534.
2. United States Department of Health and Human Services, United States Department of Agriculture (DHHS/DA). Dietary Guidelines for Americans 2015-2020, 8th edition. DHHS/DA 2015 Dec PDF.
3. Eckel RH, Jakicic JM, Ard JD, et al. 2013 AHA/ACC guideline on lifestyle management to reduce cardiovascular risk: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2014 Jun 24;129(25 Suppl 2):S76-99, corrections can be found in Circulation 2014 Jun 24;129(25 Suppl 2):S100 and Circulation 2015 Jan 27;131(4):e326 .

• American Association of Clinical Endocrinologists/American College of Endocrinology/The Obesity Society (AACE/ACE/TOS)
  • grades of recommendation
    • Grade A - best evidence level 1, or best evidence level 2 but adjusted upwards for positive subjective factors
    • Grade B - best evidence level 2, or best evidence level 1 adjusted downwards for negative subjective factors, or best evidence level 3 adjusted upwards for positive subjective factors
    • Grade C - best evidence level 3, or best evidence level 2 adjusted downwards for negative subjective factors, or best evidence level 4 adjusted upwards for positive subjective factors
    • Grade D - best evidence level 4, or best evidence level 3 adjusted downwards for negative subjective factors, or < two-thirds consensus (regardless of evidence level)
  • levels of evidence
    • Best Evidence Rating Level (BEL) 1 - randomized trials or meta-analysis of randomized trials
    • Best Evidence Rating Level (BEL) 2 - nonrandomized controlled trial, prospective cohort study, retrospective case-control study, or meta-analysis of these types of studies
    • Best Evidence Rating Level (BEL) 3 - cross-sectional study, surveillance study, consecutive case series, or single case reports
    • Best Evidence Rating Level (BEL) 4 - no evidence (theory, opinion, consensus, review, or preclinical study)
  • Reference - AACE/ACE/TOS guideline on healthy eating for prevention and treatment of metabolic and endocrine diseases in adults (Endocr Pract 2013 Sep-Oct;19 Suppl 3:1)

• American Heart Association (AHA) grading system
  • classifications of recommendations
    • Class I - procedure or treatment should be performed or administered
    • Class IIa - reasonable to perform procedure or administer treatment, but additional studies with focused objectives needed
    • Class IIb - procedure or treatment may be considered; additional studies with broad objectives needed, additional registry data would be useful
    • Class III - procedure or treatment should not be performed or administered because it is not helpful or may be harmful
      • Class III ratings may be subclassified as Class III No Benefit or Class III Harm
  • levels of evidence
    • Level A - high-quality evidence from > 1 randomized controlled trial or meta-analysis of high-quality randomized controlled trials
    • Level B-R - moderate-quality evidence from ≥ 1 randomized controlled trial or meta-analysis of moderate-quality randomized controlled trials
    • Level B-NR - moderate-quality evidence from ≥ 1 well-designed nonrandomized trial, observational studies, or registry studies, or meta-analysis of such studies
    • Level C-LD - randomized or nonrandomized studies with methodological limitations or meta-analyses of such studies
    • Level C-EO - consensus of expert opinion based on clinical experience
  • Reference - AHA scientific statement on omega-3 polyunsaturated fatty acid (fish oil) supplementation and prevention of clinical cardiovascular disease (Circulation 2017 Apr 11;135(15):e867)

• American College of Cardiology/American Heart Association (ACC/AHA) grading system for recommendations
  • classes of recommendations
    • Class I (Strong) - should be performed or administered; indicated/useful/effective/beneficial
    • Class IIa (Moderate) - reasonable to perform or administer; can be useful/effective/beneficial
    • Class IIb (Weak) - may be considered; usefulness/effectiveness is unknown/unclear/uncertain or not well established
    • Class III: No Benefit (Moderate) - should not be performed or administered; not indicated/useful/effective/beneficial
    • Class III: Harm (Strong) - should not be performed or administered; potentially harmful, causes harm, or associated with excess morbidity/mortality
  • levels of evidence
    • Level A - high-quality evidence from > 1 randomized controlled trial (RCT), meta-analyses of high-quality RCTs, or ≥ 1 RCTs corroborated by high-quality registry studies
    • Level B-R - moderate-quality evidence from ≥ 1 RCTs or meta-analysis of moderate-quality RCTs
    • Level B-NR - moderate-quality evidence from ≥ 1 well-designed, well-executed nonrandomized studies, observational studies, or registry studies, or meta-analysis of such studies
    • Level C-LD - randomized or nonrandomized observational or registry studies with limitations of design or execution, meta-analyses of such studies, or physiological or mechanistic studies in human subjects
    • Level C-EO - consensus of expert opinion based on clinical experience
  • PubMed30879355CirculationCirculation2019091014011e596-e646e596Reference - ACC/AHA guideline on primary prevention of cardiovascular disease (Circulation 2019 Sep 10;140(11):e596 or J Am Coll Cardiol 2019 Sep 10;74(10):1376)

• American College of Cardiology/American Heart Association (ACC/AHA) grading system for recommendations
  • classifications of recommendations
    • Class I - procedure or treatment should be performed or administered
    • Class IIa - reasonable to perform procedure or administer treatment, but additional studies with focused objectives needed
    • Class IIb - procedure or treatment may be considered; additional studies with broad objectives needed, additional registry data would be useful
    • Class III - procedure or treatment should not be performed or administered because it is not helpful or may be harmful
      • Class III ratings may be subclassified as Class III No Benefit or Class III Harm
  • levels of evidence
    • Level A - data derived from multiple randomized clinical trials or meta-analyses
    • Level B - data derived from single randomized trial or nonrandomized studies
    • Level C - only expert opinion, case studies, or standard of care
  • Reference - 2013 ACC/AHA guideline on lifestyle management to reduce cardiovascular risk (Circulation 2014 Jun 24;129(25 Suppl 2):S76), corrections can be found in Circulation 2014 Jun 24;129(25 Suppl 2):S100 and Circulation 2015 Jan 27;131(4):e326

• Hypertension Canada grades of recommendations
  • Grade A - recommendations based on randomized trials (or systematic reviews) with high levels of internal validity and statistical precision for which study results can be directly applied to patients because of similar clinical characteristics and clinical evidence of study outcomes
  • Grade B - recommendations based on randomized trials, systematic reviews, or prespecified subgroup analyses of randomized trials that have lower precision, or if there is a need to extrapolate from studies because of differing populations or reporting of validated intermediate/surrogate outcomes rather than clinically important outcomes
  • Grade C - recommendations from trials with lower levels of internal validity and/or precision, or that report unvalidated surrogate outcomes, or results from nonrandomized observational studies
  • Grade D - recommendations based on expert opinion alone
  • PubMed32389335The Canadian journal of cardiologyCan J Cardiol20200501365596-624596Reference - Hypertension Canada guideline on diagnosis, risk assessment, prevention, and treatment of hypertension in adults and children (Can J Cardiol 2020 May;36(5):596)

• European Society of Cardiology/European Society of Hypertension (ESC/ESH) grading system
  • classifications of recommendations
    • Class I - evidence and/or general agreement that procedure or treatment is beneficial, useful, effective
    • Class II - conflicting evidence and/or divergence of opinion about usefulness/efficacy of given treatment of procedure
      • Class IIa - weight of evidence/opinion in favor of usefulness/efficacy
      • Class IIb - usefulness/efficacy less well established by evidence/opinion
    • Class III - evidence or general agreement that procedure or treatment is not useful/effective, and in some cases may be harmful
  • levels of evidence
    • Level A - data derived from multiple randomized clinical trials or meta-analyses
    • Level B - data derived from single randomized trial or large nonrandomized studies
    • Level C - consensus opinions of experts, and/or small studies, retrospective studies, or registries
  • Reference - ESC/ESH guideline on management of arterial hypertension (Eur Heart J 2018 Sep 1;39(33):3021)

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