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Recommendations
Each recommendation has been mapped from the NHLBI grading format to the American College of Cardiology/American Heart Association Class of Recommendation/Level of Evidence (ACC/AHA COR/LOE) construct and is expressed in both formats. Because of the inherent differences in grading systems and the clinical questions driving the recommendations, alignment between the NHLBI and ACC/AHA formats is in some cases imperfect. Definitions for the NHLBI strength of recommendation (A-E, N) and quality of evidence (High, Moderate, Low) and the ACC/AHA levels of the evidence (LOE: A-C) and classes of recommendations (COR: I-III) are provided at the end of the "Major Recommendations" field.
Summary of Recommendations for Lifestyle Management
Diet
Low-density lipoprotein cholesterol (LDL-C): Advise adults who would benefit from LDL-C lowering* to:
- Consume a dietary pattern that emphasizes intake of vegetables, fruits, and whole grains; includes low-fat dairy products, poultry, fish, legumes, nontropical vegetable oils, and nuts; and limits intake of sweets, sugar-sweetened beverages, and red meats. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
- Adapt this dietary pattern to appropriate calorie requirements, personal and cultural food preferences, and nutrition therapy for other medical conditions (including diabetes).
- Achieve this pattern by following plans such as the Dietary Approaches to Stop Hypertension (DASH) dietary pattern, the U.S. Department of Agriculture (USDA) Food Pattern, or the AHA Diet.
- Aim for a dietary pattern that achieves 5% to 6% of calories from saturated fat. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
- Reduce percent of calories from saturated fat. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
- Reduce percent of calories from trans fat. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
Blood pressure (BP): Advise adults who would benefit from BP lowering to:
- Consume a dietary pattern that emphasizes intake of vegetables, fruits, and whole grains; includes low-fat dairy products, poultry, fish, legumes, nontropical vegetable oils, and nuts; and limits intake of sweets, sugar-sweetened beverages, and red meats. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
- Adapt this dietary pattern to appropriate calorie requirements, personal and cultural food preferences, and nutrition therapy for other medical conditions (including diabetes).
- Achieve this pattern by following plans such as the DASH dietary pattern, the USDA Food Pattern, or the AHA Diet.
- Lower sodium intake. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
- a. Consume no more than 2,400 mg of sodium/d; b. Further reduction of sodium intake to 1,500 mg/d can result in even greater reduction in BP; and c. Even without achieving these goals, reducing sodium intake by at least 1,000 mg/d lowers BP. NHLBI Grade: B (Moderate); ACC/AHA COR: IIa; ACC/AHA LOE: B
- Combine the DASH dietary pattern with lower sodium intake. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
Physical Activity
Lipids
- In general, advise adults to engage in aerobic physical activity to reduce LDL-C and non-high-density lipoprotein cholesterol (non–HDL-C): 3–4 sessions per week, lasting on average 40 minutes per session, and involving moderate- to vigorous-intensity physical activity. NHLBI Grade: B (Moderate); ACC/AHA COR: IIa; ACC/AHA LOE: A
BP
- In general, advise adults to engage in aerobic physical activity to lower BP: 3 to 4 sessions per week, lasting on average 40 minutes per session, and involving moderate- to vigorous-intensity physical activity. NHLBI Grade: B (Moderate); ACC/AHA COR: IIa; ACC/AHA LOE: A
*Refer to the NGC summary 2013 ACC/AHA guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular risk in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines.
See Tables 7-10, 13, 15, and 16 in the original guideline document for additional diet and physical activity guidelines and resources.
Definitions:
NHLBI Grading of the Strength of Recommendations
Grade | Strength of Recommendation* |
---|---|
A | Strong recommendation There is high certainty based on evidence that the net benefit† is substantial. |
B | Moderate recommendation There is moderate certainty based on evidence that the net benefit is moderate to substantial, or there is high certainty that the net benefit is moderate. |
C | Weak recommendation There is at least moderate certainty based on evidence that there is a small net benefit. |
D | Recommendation against There is at least moderate certainty based on evidence that there is no net benefit or that risks/harms outweigh benefits. |
E | Expert opinion ("There is insufficient evidence or evidence is unclear or conflicting, but this is what the Work Group recommends.") Net benefit is unclear. Balance of benefits and harms cannot be determined because of no evidence, insufficient evidence, unclear evidence, or conflicting evidence, but the Work Group thought it was important to provide clinical guidance and make a recommendation. Further research is recommended in this area. |
N | No recommendation for or against ("There is insufficient evidence or evidence is unclear or conflicting.") Net benefit is unclear. Balance of benefits and harms cannot be determined because of no evidence, insufficient evidence, unclear evidence, or conflicting evidence, and the Work Group thought no recommendation should be made. Further research is recommended in this area. |
*In most cases, the strength of the recommendation should be closely aligned with the quality of the evidence; however, under some circumstances, there may be valid reasons for making recommendations that are not closely aligned with the quality of the evidence (e.g., strong recommendation when the evidence quality is moderate, such as smoking cessation to reduce cardiovascular disease [CVD] risk or ordering an electrocardiogram [ECG] as part of the initial diagnostic work-up for a patient presenting with possible myocardial infarction [MI]). Those situations should be limited and the rationale explained clearly by the Work Group.
†Net benefit is defined as benefits minus risks/harms of the service/intervention.
NHLBI Quality Rating of the Strength of Evidence
Type of Evidence | Quality Rating* |
---|---|
| High |
| Moderate |
| Low |
*In some cases, other evidence, such as large all-or-none case series (e.g., jumping from airplanes or tall structures), can represent high- or moderate-quality evidence. In such cases, the rationale for the evidence rating exception should be explained by the Work Group and clearly justified.
†"Well-designed, well-executed" refers to studies that directly address the question; use adequate randomization, blinding, and allocation concealment; are adequately powered; use intention-to-treat analyses; and have high follow-up rates.
‡Limitations include concerns with the design and execution of a study that result in decreased confidence in the true estimate of the effect. Examples of such limitations include but are not limited to: inadequate randomization, lack of blinding of study participants or outcome assessors, inadequate power, outcomes of interest that are not prespecified for the primary outcomes, low follow-up rates, and findings based on subgroup analyses. Whether the limitations are considered minor or major is based on the number and severity of flaws in design or execution. Rules for determining whether the limitations are considered minor or major and how they will affect rating of the individual studies will be developed collaboratively with the methodology team.
§Nonrandomized controlled studies refer to intervention studies where assignment to intervention and comparison groups is not random (e.g., quasi-experimental study design).
¶Observational studies include prospective and retrospective cohort, case-control, and cross-sectional studies.
Applying Classification of Recommendations and Level of Evidence
Size of Treatment Effect | |||||||
---|---|---|---|---|---|---|---|
CLASS I Benefit >>> Risk Procedure/Treatment SHOULD be performed/ administered | CLASS IIa Benefit >> Risk Additional studies with focused objectives needed IT IS REASONABLE to perform procedure/administer treatment | CLASS IIb Benefit ≥ Risk Additional studies with broad objectives needed; additional registry data would be helpful Procedure/Treatment MAY BE CONSIDERED | CLASS III No Benefit or Class III Harm | ||||
Procedure/Test | Treatment | ||||||
COR III: No Benefit | Not helpful | No proven benefit | |||||
COR III: Harm | Excess cost without benefit or harmful | Harmful to patients | |||||
Estimate of Certainty (Precision) of Treatment Effect | LEVEL A Multiple populations evaluated* Data derived from multiple randomized clinical trials or meta-analyses |
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LEVEL B Limited populations evaluated* Data derived from a single randomized trial or nonrandomized studies |
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LEVEL C Very limited populations evaluated* Only consensus opinion of experts, case studies, or standard of care |
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|
A recommendation with Level of Evidence B or C does not imply the recommendation is weak. Many important clinical questions addressed in the guidelines do not lend themselves to clinical trials. Even when randomized trials are unavailable, there may be a very clear clinical consensus that a particular test or therapy is useful or effective.
*Data available from clinical trials or registries about the usefulness/efficacy in different subpopulations, such as sex, age, history of diabetes, history of prior myocardial infarction, history of heart failure, and prior aspirin use.
†For comparative-effectiveness recommendations (Class I and IIa; Level of Evidence A and B only), studies that support the use of comparator verbs should involve direct comparisons of the treatments or strategies being evaluated.
Recommendations
Each recommendation has been mapped from the NHLBI grading format to the American College of Cardiology/American Heart Association Class of Recommendation/Level of Evidence (ACC/AHA COR/LOE) construct and is expressed in both formats. Because of the inherent differences in grading systems and the clinical questions driving the recommendations, alignment between the NHLBI and ACC/AHA formats is in some cases imperfect. Definitions for the NHLBI strength of recommendation (A-E, N) and quality of evidence (High, Moderate, Low) and the ACC/AHA levels of the evidence (LOE: A-C) and classes of recommendations (COR: I-III) are provided at the end of the "Major Recommendations" field.
Summary of Recommendations for Lifestyle Management
Diet
Low-density lipoprotein cholesterol (LDL-C): Advise adults who would benefit from LDL-C lowering* to:
- Consume a dietary pattern that emphasizes intake of vegetables, fruits, and whole grains; includes low-fat dairy products, poultry, fish, legumes, nontropical vegetable oils, and nuts; and limits intake of sweets, sugar-sweetened beverages, and red meats. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
- Adapt this dietary pattern to appropriate calorie requirements, personal and cultural food preferences, and nutrition therapy for other medical conditions (including diabetes).
- Achieve this pattern by following plans such as the Dietary Approaches to Stop Hypertension (DASH) dietary pattern, the U.S. Department of Agriculture (USDA) Food Pattern, or the AHA Diet.
- Aim for a dietary pattern that achieves 5% to 6% of calories from saturated fat. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
- Reduce percent of calories from saturated fat. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
- Reduce percent of calories from trans fat. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
Blood pressure (BP): Advise adults who would benefit from BP lowering to:
- Consume a dietary pattern that emphasizes intake of vegetables, fruits, and whole grains; includes low-fat dairy products, poultry, fish, legumes, nontropical vegetable oils, and nuts; and limits intake of sweets, sugar-sweetened beverages, and red meats. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
- Adapt this dietary pattern to appropriate calorie requirements, personal and cultural food preferences, and nutrition therapy for other medical conditions (including diabetes).
- Achieve this pattern by following plans such as the DASH dietary pattern, the USDA Food Pattern, or the AHA Diet.
- Lower sodium intake. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
- a. Consume no more than 2,400 mg of sodium/d; b. Further reduction of sodium intake to 1,500 mg/d can result in even greater reduction in BP; and c. Even without achieving these goals, reducing sodium intake by at least 1,000 mg/d lowers BP. NHLBI Grade: B (Moderate); ACC/AHA COR: IIa; ACC/AHA LOE: B
- Combine the DASH dietary pattern with lower sodium intake. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
Physical Activity
Lipids
- In general, advise adults to engage in aerobic physical activity to reduce LDL-C and non-high-density lipoprotein cholesterol (non–HDL-C): 3–4 sessions per week, lasting on average 40 minutes per session, and involving moderate- to vigorous-intensity physical activity. NHLBI Grade: B (Moderate); ACC/AHA COR: IIa; ACC/AHA LOE: A
BP
- In general, advise adults to engage in aerobic physical activity to lower BP: 3 to 4 sessions per week, lasting on average 40 minutes per session, and involving moderate- to vigorous-intensity physical activity. NHLBI Grade: B (Moderate); ACC/AHA COR: IIa; ACC/AHA LOE: A
*Refer to the NGC summary 2013 ACC/AHA guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular risk in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines.
See Tables 7-10, 13, 15, and 16 in the original guideline document for additional diet and physical activity guidelines and resources.
Definitions:
NHLBI Grading of the Strength of Recommendations
Grade | Strength of Recommendation* |
---|---|
A | Strong recommendation There is high certainty based on evidence that the net benefit† is substantial. |
B | Moderate recommendation There is moderate certainty based on evidence that the net benefit is moderate to substantial, or there is high certainty that the net benefit is moderate. |
C | Weak recommendation There is at least moderate certainty based on evidence that there is a small net benefit. |
D | Recommendation against There is at least moderate certainty based on evidence that there is no net benefit or that risks/harms outweigh benefits. |
E | Expert opinion ("There is insufficient evidence or evidence is unclear or conflicting, but this is what the Work Group recommends.") Net benefit is unclear. Balance of benefits and harms cannot be determined because of no evidence, insufficient evidence, unclear evidence, or conflicting evidence, but the Work Group thought it was important to provide clinical guidance and make a recommendation. Further research is recommended in this area. |
N | No recommendation for or against ("There is insufficient evidence or evidence is unclear or conflicting.") Net benefit is unclear. Balance of benefits and harms cannot be determined because of no evidence, insufficient evidence, unclear evidence, or conflicting evidence, and the Work Group thought no recommendation should be made. Further research is recommended in this area. |
*In most cases, the strength of the recommendation should be closely aligned with the quality of the evidence; however, under some circumstances, there may be valid reasons for making recommendations that are not closely aligned with the quality of the evidence (e.g., strong recommendation when the evidence quality is moderate, such as smoking cessation to reduce cardiovascular disease [CVD] risk or ordering an electrocardiogram [ECG] as part of the initial diagnostic work-up for a patient presenting with possible myocardial infarction [MI]). Those situations should be limited and the rationale explained clearly by the Work Group.
†Net benefit is defined as benefits minus risks/harms of the service/intervention.
NHLBI Quality Rating of the Strength of Evidence
Type of Evidence | Quality Rating* |
---|---|
| High |
| Moderate |
| Low |
*In some cases, other evidence, such as large all-or-none case series (e.g., jumping from airplanes or tall structures), can represent high- or moderate-quality evidence. In such cases, the rationale for the evidence rating exception should be explained by the Work Group and clearly justified.
†"Well-designed, well-executed" refers to studies that directly address the question; use adequate randomization, blinding, and allocation concealment; are adequately powered; use intention-to-treat analyses; and have high follow-up rates.
‡Limitations include concerns with the design and execution of a study that result in decreased confidence in the true estimate of the effect. Examples of such limitations include but are not limited to: inadequate randomization, lack of blinding of study participants or outcome assessors, inadequate power, outcomes of interest that are not prespecified for the primary outcomes, low follow-up rates, and findings based on subgroup analyses. Whether the limitations are considered minor or major is based on the number and severity of flaws in design or execution. Rules for determining whether the limitations are considered minor or major and how they will affect rating of the individual studies will be developed collaboratively with the methodology team.
§Nonrandomized controlled studies refer to intervention studies where assignment to intervention and comparison groups is not random (e.g., quasi-experimental study design).
¶Observational studies include prospective and retrospective cohort, case-control, and cross-sectional studies.
Applying Classification of Recommendations and Level of Evidence
Size of Treatment Effect | |||||||
---|---|---|---|---|---|---|---|
CLASS I Benefit >>> Risk Procedure/Treatment SHOULD be performed/ administered | CLASS IIa Benefit >> Risk Additional studies with focused objectives needed IT IS REASONABLE to perform procedure/administer treatment | CLASS IIb Benefit ≥ Risk Additional studies with broad objectives needed; additional registry data would be helpful Procedure/Treatment MAY BE CONSIDERED | CLASS III No Benefit or Class III Harm | ||||
Procedure/Test | Treatment | ||||||
COR III: No Benefit | Not helpful | No proven benefit | |||||
COR III: Harm | Excess cost without benefit or harmful | Harmful to patients | |||||
Estimate of Certainty (Precision) of Treatment Effect | LEVEL A Multiple populations evaluated* Data derived from multiple randomized clinical trials or meta-analyses |
|
|
|
| ||
LEVEL B Limited populations evaluated* Data derived from a single randomized trial or nonrandomized studies |
|
|
|
| |||
LEVEL C Very limited populations evaluated* Only consensus opinion of experts, case studies, or standard of care |
|
|
|
|
A recommendation with Level of Evidence B or C does not imply the recommendation is weak. Many important clinical questions addressed in the guidelines do not lend themselves to clinical trials. Even when randomized trials are unavailable, there may be a very clear clinical consensus that a particular test or therapy is useful or effective.
*Data available from clinical trials or registries about the usefulness/efficacy in different subpopulations, such as sex, age, history of diabetes, history of prior myocardial infarction, history of heart failure, and prior aspirin use.
†For comparative-effectiveness recommendations (Class I and IIa; Level of Evidence A and B only), studies that support the use of comparator verbs should involve direct comparisons of the treatments or strategies being evaluated.
Recommendations
Each recommendation has been mapped from the NHLBI grading format to the American College of Cardiology/American Heart Association Class of Recommendation/Level of Evidence (ACC/AHA COR/LOE) construct and is expressed in both formats. Because of the inherent differences in grading systems and the clinical questions driving the recommendations, alignment between the NHLBI and ACC/AHA formats is in some cases imperfect. Definitions for the NHLBI strength of recommendation (A-E, N) and quality of evidence (High, Moderate, Low) and the ACC/AHA levels of the evidence (LOE: A-C) and classes of recommendations (COR: I-III) are provided at the end of the "Major Recommendations" field.
Summary of Recommendations for Lifestyle Management
Diet
Low-density lipoprotein cholesterol (LDL-C): Advise adults who would benefit from LDL-C lowering* to:
- Consume a dietary pattern that emphasizes intake of vegetables, fruits, and whole grains; includes low-fat dairy products, poultry, fish, legumes, nontropical vegetable oils, and nuts; and limits intake of sweets, sugar-sweetened beverages, and red meats. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
- Adapt this dietary pattern to appropriate calorie requirements, personal and cultural food preferences, and nutrition therapy for other medical conditions (including diabetes).
- Achieve this pattern by following plans such as the Dietary Approaches to Stop Hypertension (DASH) dietary pattern, the U.S. Department of Agriculture (USDA) Food Pattern, or the AHA Diet.
- Aim for a dietary pattern that achieves 5% to 6% of calories from saturated fat. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
- Reduce percent of calories from saturated fat. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
- Reduce percent of calories from trans fat. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
Blood pressure (BP): Advise adults who would benefit from BP lowering to:
- Consume a dietary pattern that emphasizes intake of vegetables, fruits, and whole grains; includes low-fat dairy products, poultry, fish, legumes, nontropical vegetable oils, and nuts; and limits intake of sweets, sugar-sweetened beverages, and red meats. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
- Adapt this dietary pattern to appropriate calorie requirements, personal and cultural food preferences, and nutrition therapy for other medical conditions (including diabetes).
- Achieve this pattern by following plans such as the DASH dietary pattern, the USDA Food Pattern, or the AHA Diet.
- Lower sodium intake. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
- a. Consume no more than 2,400 mg of sodium/d; b. Further reduction of sodium intake to 1,500 mg/d can result in even greater reduction in BP; and c. Even without achieving these goals, reducing sodium intake by at least 1,000 mg/d lowers BP. NHLBI Grade: B (Moderate); ACC/AHA COR: IIa; ACC/AHA LOE: B
- Combine the DASH dietary pattern with lower sodium intake. NHLBI Grade: A (Strong); ACC/AHA COR: I; ACC/AHA LOE: A
Physical Activity
Lipids
- In general, advise adults to engage in aerobic physical activity to reduce LDL-C and non-high-density lipoprotein cholesterol (non–HDL-C): 3–4 sessions per week, lasting on average 40 minutes per session, and involving moderate- to vigorous-intensity physical activity. NHLBI Grade: B (Moderate); ACC/AHA COR: IIa; ACC/AHA LOE: A
BP
- In general, advise adults to engage in aerobic physical activity to lower BP: 3 to 4 sessions per week, lasting on average 40 minutes per session, and involving moderate- to vigorous-intensity physical activity. NHLBI Grade: B (Moderate); ACC/AHA COR: IIa; ACC/AHA LOE: A
*Refer to the NGC summary 2013 ACC/AHA guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular risk in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines.
See Tables 7-10, 13, 15, and 16 in the original guideline document for additional diet and physical activity guidelines and resources.
Definitions:
NHLBI Grading of the Strength of Recommendations
Grade | Strength of Recommendation* |
---|---|
A | Strong recommendation There is high certainty based on evidence that the net benefit† is substantial. |
B | Moderate recommendation There is moderate certainty based on evidence that the net benefit is moderate to substantial, or there is high certainty that the net benefit is moderate. |
C | Weak recommendation There is at least moderate certainty based on evidence that there is a small net benefit. |
D | Recommendation against There is at least moderate certainty based on evidence that there is no net benefit or that risks/harms outweigh benefits. |
E | Expert opinion ("There is insufficient evidence or evidence is unclear or conflicting, but this is what the Work Group recommends.") Net benefit is unclear. Balance of benefits and harms cannot be determined because of no evidence, insufficient evidence, unclear evidence, or conflicting evidence, but the Work Group thought it was important to provide clinical guidance and make a recommendation. Further research is recommended in this area. |
N | No recommendation for or against ("There is insufficient evidence or evidence is unclear or conflicting.") Net benefit is unclear. Balance of benefits and harms cannot be determined because of no evidence, insufficient evidence, unclear evidence, or conflicting evidence, and the Work Group thought no recommendation should be made. Further research is recommended in this area. |
*In most cases, the strength of the recommendation should be closely aligned with the quality of the evidence; however, under some circumstances, there may be valid reasons for making recommendations that are not closely aligned with the quality of the evidence (e.g., strong recommendation when the evidence quality is moderate, such as smoking cessation to reduce cardiovascular disease [CVD] risk or ordering an electrocardiogram [ECG] as part of the initial diagnostic work-up for a patient presenting with possible myocardial infarction [MI]). Those situations should be limited and the rationale explained clearly by the Work Group.
†Net benefit is defined as benefits minus risks/harms of the service/intervention.
NHLBI Quality Rating of the Strength of Evidence
Type of Evidence | Quality Rating* |
---|---|
| High |
| Moderate |
| Low |
*In some cases, other evidence, such as large all-or-none case series (e.g., jumping from airplanes or tall structures), can represent high- or moderate-quality evidence. In such cases, the rationale for the evidence rating exception should be explained by the Work Group and clearly justified.
†"Well-designed, well-executed" refers to studies that directly address the question; use adequate randomization, blinding, and allocation concealment; are adequately powered; use intention-to-treat analyses; and have high follow-up rates.
‡Limitations include concerns with the design and execution of a study that result in decreased confidence in the true estimate of the effect. Examples of such limitations include but are not limited to: inadequate randomization, lack of blinding of study participants or outcome assessors, inadequate power, outcomes of interest that are not prespecified for the primary outcomes, low follow-up rates, and findings based on subgroup analyses. Whether the limitations are considered minor or major is based on the number and severity of flaws in design or execution. Rules for determining whether the limitations are considered minor or major and how they will affect rating of the individual studies will be developed collaboratively with the methodology team.
§Nonrandomized controlled studies refer to intervention studies where assignment to intervention and comparison groups is not random (e.g., quasi-experimental study design).
¶Observational studies include prospective and retrospective cohort, case-control, and cross-sectional studies.
Applying Classification of Recommendations and Level of Evidence
Size of Treatment Effect | |||||||
---|---|---|---|---|---|---|---|
CLASS I Benefit >>> Risk Procedure/Treatment SHOULD be performed/ administered | CLASS IIa Benefit >> Risk Additional studies with focused objectives needed IT IS REASONABLE to perform procedure/administer treatment | CLASS IIb Benefit ≥ Risk Additional studies with broad objectives needed; additional registry data would be helpful Procedure/Treatment MAY BE CONSIDERED | CLASS III No Benefit or Class III Harm | ||||
Procedure/Test | Treatment | ||||||
COR III: No Benefit | Not helpful | No proven benefit | |||||
COR III: Harm | Excess cost without benefit or harmful | Harmful to patients | |||||
Estimate of Certainty (Precision) of Treatment Effect | LEVEL A Multiple populations evaluated* Data derived from multiple randomized clinical trials or meta-analyses |
|
|
|
| ||
LEVEL B Limited populations evaluated* Data derived from a single randomized trial or nonrandomized studies |
|
|
|
| |||
LEVEL C Very limited populations evaluated* Only consensus opinion of experts, case studies, or standard of care |
|
|
|
|
A recommendation with Level of Evidence B or C does not imply the recommendation is weak. Many important clinical questions addressed in the guidelines do not lend themselves to clinical trials. Even when randomized trials are unavailable, there may be a very clear clinical consensus that a particular test or therapy is useful or effective.
*Data available from clinical trials or registries about the usefulness/efficacy in different subpopulations, such as sex, age, history of diabetes, history of prior myocardial infarction, history of heart failure, and prior aspirin use.
†For comparative-effectiveness recommendations (Class I and IIa; Level of Evidence A and B only), studies that support the use of comparator verbs should involve direct comparisons of the treatments or strategies being evaluated.
OBJECTIVE: To evaluate evidence that particular dietary patterns, nutrient intake, and levels and types of physical activity can play a major role in cardiovascular disease (CVD) prevention and treatment through effects on modifiable CVD risk factors (i.e., blood pressure [BP] and lipids).
Guidelines are copyright © 2014 American College of Cardiology/American Heart Association. All rights reserved. The summary is provided by the Agency for Healthcare Research and Quality.