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TABLE OF CONTENTS:
INTRODUCTION:
A direct comparison of National Heart, Lung, and Blood Institute (NHLBI) and Veterans Health Administration, Department of Defense (VHA/DoD) recommendations for lipid screening for primary prevention of coronary heart disease (CHD) and atherosclerotic cardiovascular disease (ASCVD) in adults is provided in the tables below. The guidelines address both cholesterol testing and clinical management of high cholesterol, including primary and secondary prevention. Recommendations for clinical management and secondary prevention of dyslipidemia, however, are beyond the scope of this synthesis.
Table 1 gives a broad overview of the four guidelines. Table 2 details the recommendations for lipid screening and risk factor assessment for adults. Benefits and harms associated with screening are listed in Table 3. The supporting evidence is classified and identified with the major recommendations for VHA/DoD, and the definitions of each rating scheme are included in Table 4. Table 4 also includes references supporting specific recommendations for VHA/DoD, when applicable. Following the content comparison tables and discussion, the areas of agreement and differences among the guidelines are identified.
In formulating their recommendations, VHA/DoD drew heavily from NHLBI's Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III [ATPIII]) and from the 2001 U. S. Preventive Services Task Force (USPSTF) recommendations for lipid screening.
Notably, since the publication of ATP III, 5 major clinical trials of statin therapy with clinical end points have been published. These trials addressed issues that were not examined in previous clinical trials of cholesterol-lowering therapy. In 2004 the NHLBI issued an addendum to their guideline that reviews the results of these recent trials and assesses their implications for cholesterol management. Proposed modifications to the NHLBI guideline recommendations have been included in this synthesis.
Listed below are common abbreviations used within the tables and discussions:
TABLE 2: COMPARISON OF RECOMMENDATIONS FOR LIPID SCREENING IN THE PRIMARY PREVENTION OF CORONARY HEART DISEASE AND ATHEROSCLEROTIC CARDIOVASCULAR DISEASE | |
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Who Should Be Screened? | |
NHLBI (2001 & 2004) |
|
VHA/DoD (2006) |
|
What Type of Screening Test Should Be Used? | |
NHLBI (2001 & 2004) |
|
VHA/DoD (2006) |
Lipid levels are preferably obtained in a fasting state. However, if the testing opportunity is nonfasting, only the values for TC and HDL will be usable. In otherwise low-risk person (0 to 1 risk factor), further testing is not required if the HDL-C level is >40 mg/dL and TC is <200 mg/dL. For persons with multiple (2+) risk factors, LDL-C levels are needed as a guide to clinical management.
Lipid Screening Test
|
What Other Important Risk Factors for CHD Should Be Assessed? | |
NHLBI (2001 & 2004) |
2004 Addendum
|
VHA/DoD (2006) |
10-Year Risk Score for CVD
|
How Should Serum Lipid Concentrations Be Classified in Terms of Risk? | |
NHLBI (2001 & 2004) |
ATP III Classification of LDL, Total, and HDL-Cholesterol (mg/dL)
|
VHA/DoD (2006) |
|
What Is the Significance of the Lipid Screening Results for Future Management Decisions? | |
NHLBI (2001 & 2004) |
2004 Addendum The ATP III goals and cutpoints for therapeutic lifestyle changes and drug therapy in different risk categories, and proposed modifications in the treatment algorithm for LDL cholesterol based on evidence from recent clinical trials, are presented below. Essential modifications are highlighted in the footnotes and summary that follow. Risk Category: High risk: CHD1 or CHD risk equivalents2 (10-year risk >20%)
Risk Category: Moderately high risk: 2+ risk factors3 (10-year risk 10% to 20%)4
Risk Category: Moderate risk: 2+ risk factors3 (10-year risk <10%)4 Risk Category: Lower risk: 0 to 1 risk factor5 1Coronary heart disease (CHD) includes history of myocardial infarction, unstable angina, stable angina, coronary artery procedures (angioplasty or bypass surgery), or evidence of clinically significant myocardial ischemia. 2CHD risk equivalents include clinical manifestations of noncoronary forms of atherosclerotic disease (peripheral arterial disease, abdominal aortic aneurysm, and carotid artery disease [transient ischemic attacks or stroke of carotid origin or >50% obstruction of a carotid artery]), diabetes, and 2+ risk factors with 10-year risk for hard CHD >20%. 3Risk factors include cigarette smoking, hypertension (BP >140/90 mm Hg or on antihypertensive medication), low high-density lipoprotein (HDL) cholesterol (<40 mg/dL), family history of premature CHD (CHD in male first-degree relative <55 years of age; CHD in female first-degree relative <65 years of age), and age (men >45 years; women >55 years). 4Electronic 10-year risk calculators are available at www.nhlbi.nih.gov/guidelines/cholesterol. 5Almost all people with zero or 1 risk factor have a 10-year risk <10%, and 10-year risk assessment in people with zero or 1 risk factor is thus not necessary. 6Very high risk favors the optional LDL-C goal of <70 mg/dL, and in patients with high triglycerides, non-HDL-C <100 mg/dL. 7Optional LDL-C goal <100 mg/dL. 8Any person at high risk or moderately high risk who has lifestyle-related risk factors (e.g., obesity, physical inactivity, elevated triglyceride, low HDL-C, or metabolic syndrome) is a candidate for therapeutic lifestyle changes to modify these risk factors regardless of LDL-C level. 9When LDL-lowering drug therapy is employed, it is advised that intensity of therapy be sufficient to achieve at least a 30% to 40% reduction in LDL-C levels. 10If baseline LDL-C is <100 mg/dL, institution of an LDL-lowering drug is a therapeutic option on the basis of available clinical trial results. If a high-risk person has high triglycerides or low HDL-C, combining a fibrate or nicotinic acid with an LDL-lowering drug can be considered. 11For moderately high-risk persons, when LDL-C level is 100 to 129 mg/dL, at baseline or on lifestyle therapy, initiation of an LDL-lowering drug to achieve an LDL-C level <100 mg/dL is a therapeutic option on the basis of available clinical trial results. Summary of Modifications
|
VHA/DoD (2006) |
Non-Pharmacologic Therapy
Goals of Therapy for Primary Prevention
Drug Therapy for Primary Prevention
|
How Frequently Should Patients Be Screened? | |
NHLBI (2001 & 2004) |
|
VHA/DoD (2006) |
Recommended Screening Schedules for Dyslipidemia For young adults (men <age 35; women <age 45)
For middle-aged adults (men >age 35; women >age 45)
For elderly patients up to age 75 years
For elderly patients >age 75
|
TABLE 4: EVIDENCE AND RECOMMENDATION RATING SCHEMES | ||||||||||||||||||||||||||
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NHLBI (2001 & 2004) |
Type of Evidence:
Strength of Evidence:
|
|||||||||||||||||||||||||
VHA/DoD (2006) |
Strength of the Recommendations A: A strong recommendation that the clinicians provide the intervention to eligible patients. B: A recommendation that clinicians provide (the service) to eligible patients. C: No recommendation for or against the routine provision of the intervention is made. D: Recommendation is made against routinely providing the intervention to asymptomatic patients. I: The conclusion is that the evidence is insufficient to recommend for or against routinely providing the intervention.
Quality of Evidence I: At least one properly done randomized controlled trial II-1: Well designed controlled trails without randomization II-2: Well designed cohort or case-control analytic study, preferably from more than one source II-3: Multiple time series evidence with/without intervention; dramatic results of uncontrolled experiment III: Opinion of respected authorities, descriptive studies, case reports, and expert committees Overall Quality Good: High grade evidence (I or II-1) directly linked to health outcome Fair: High grade evidence (I or II-1) linked to intermediate outcome; or moderate grade evidence (II-2 or II-3) directly linked to health outcome Poor: Level III evidence or no linkage of evidence to health outcome. Net Effect of Intervention Substantial:
Moderate:
Small:
Zero or Negative:
References Supporting the Recommendations 27th Bethesda Conference. Matching the Intensity of Risk Factor Management with the Hazard for Coronary Disease Events. September 14-15, 1995. J Am Coll Cardiol 1996 Apr;27(5):957-1047. PubMed A multicenter comparative trial of lovastatin and pravastatin in the treatment of hypercholesterolemia. The Lovastatin Pravastatin Study Group. Am J Cardiol 1993 Apr 1;71(10):810-5. PubMed Downs JR, Clearfield M, Weis S, Whitney E, Shapiro DR, Beere PA, Langendorfer A, Stein EA, Kruyer W, Gotto AM Jr. Primary prevention of acute coronary events with lovastatin in men and women with average cholesterol levels: results of AFCAPS/TexCAPS. Air Force/Texas Coronary Atherosclerosis Prevention Study. JAMA 1998 May 27;279(20):1615-22. PubMed Ford DE, Mead LA, Chang PP, Cooper-Patrick L, Wang NY, Klag MJ. Depression is a risk factor for coronary artery disease in men: the precursors study. Arch Intern Med 1998 Jul 13;158(13):1422-6. PubMed Greenland P, Abrams J, Aurigemma GP, Bond MG, Clark LT, Criqui MH, Crouse JR 3rd, Friedman L, Fuster V, Herrington DM, Kuller LH, Ridker PM, Roberts WC, Stanford W, Stone N, Swan HJ, Taubert KA, Wexler L. Prevention Conference V: beyond secondary prevention: identifying the high-risk patient for primary prevention: noninvasive tests of atherosclerotic burden: Writing Group III. Circulation 2000 Jan 4;101(1):E16-22. PubMed Greenland P, LaBree L, Azen SP, Doherty TM, Detrano RC. Coronary artery calcium score combined with Framingham score for risk prediction in asymptomatic individuals. JAMA 2004 Jan 14;291(2):210-5. PubMed Grover SA, Coupal L, Hu XP. Identifying adults at increased risk of coronary disease. How well do the current cholesterol guidelines work?. JAMA 1995 Sep 13;274(10):801-6. PubMed Grover SA, Dorais M, Paradis G, Fodor JG, Frohlich JJ, McPherson R, Coupal L, Zowall H. Lipid screening to prevent coronary artery disease: a quantitative evaluation of evolving guidelines. CMAJ 2000 Nov 14;163(10):1263-9. PubMed Grundy SM, Cleeman JI, Merz CN, Brewer HB Jr, Clark LT, Hunninghake DB, Pasternak RC, Smith SC Jr, Stone NJ. Implications of recent clinical trials for the National Cholesterol Education Program Adult Treatment Panel III guidelines. Circulation 2004 Jul 13;110(2):227-39. [45 references] PubMed Grundy SM, Pasternak R, Greenland P, Smith S Jr, Fuster V. Assessment of cardiovascular risk by use of multiple-risk-factor assessment equations: a statement for healthcare professionals from the American Heart Association and the American College of Cardiology. Circulation 1999 Sep 28;100(13):1481-92. [115 references] PubMed Heart Protection Study Collaborative Group. MRC/BHF Heart Protection Study of cholesterol lowering with simvastatin in 20,536 high-risk individuals: a randomised placebo-controlled trial. Lancet 2002 Jul 6;360(9326):7-22. PubMed O'Donnell CJ. Family history, subclinical atherosclerosis, and coronary heart disease risk: barriers and opportunities for the use of family history information in risk prediction and prevention. Circulation 2004 Oct 12;110(15):2074-6. PubMed Pearson TA, Mensah GA, Alexander RW, Anderson JL, Cannon RO 3rd, Criqui M, Fadl YY, Fortmann SP, Hong Y, Myers GL, Rifai N, Smith SC Jr, Taubert K, Tracy RP, Vinicor F. Markers of inflammation and cardiovascular disease: application to clinical and public health practice: A statement for healthcare professionals from the Centers for Disease Control and Prevention and the American Heart Association. Circulation 2003 Jan 28;107(3):499-511. PubMed Pignone MP, Phillips CJ, Atkins D, Teutsch SM, Mulrow CD, Lohr KN. Screening and treating adults for lipid disorders. Am J Prev Med 2001 Apr;20(3 Suppl):77-89. [62 references] PubMed Pletcher MJ, Tice JA, Pignone M, Browner WS. Using the coronary artery calcium score to predict coronary heart disease events: a systematic review and meta-analysis. Arch Intern Med 2004 Jun 28;164(12):1285-92. PubMed Ridker PM. High-sensitivity C-reactive protein: potential adjunct for global risk assessment in the primary prevention of cardiovascular disease. Circulation 2001 Apr 3;103(13):1813-8. PubMed Screening experience and baseline characteristics in the West of Scotland Coronary Prevention Study. The WOSCOPS Study Group. West of Scotland Coronary Prevention Study. Am J Cardiol 1995 Sep 1;76(7):485-91. PubMed Sever PS, Dahlof B, Poulter NR, Wedel H, Beevers G, Caulfield M, Collins R, Kjeldsen SE, Kristinsson A, McInnes GT, Mehlsen J, Nieminen M, O'Brien E, Ostergren J. Prevention of coronary and stroke events with atorvastatin in hypertensive patients who have average or lower-than-average cholesterol concentrations, in the Anglo-Scandinian Cardiac Outcomes Trial - Lipid Lowering Arm (ASCOT-LLA): a multicentre [trunc]. Lancet 2003 Apr 5;361(9364):1149-58. PubMed Sheridan S, Pignone M, Mulrow C. Framingham-based tools to calculate the global risk of coronary heart disease: a systematic review of tools for clinicians. J Gen Intern Med 2003 Dec;18(12):1039-52. [58 references] PubMed Stone NJ, Blum C, Winslow E. Management of lipids in clinical practice. Oklahoma: Professional Communications Inc.; 1997. Stone NJ, Blum CB. Management of lipids in clinical practice. West Islip (NY): Professional Communications Inc.; 2002. 115-20 p. Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) final report. Circulation 2002 Dec 17;106(25):3143-421. PubMed US Preventive Services Task Force. Screening adults for lipid disorders: recommendations and rationale. Am J Prev Med 2001 Apr;20(3 Suppl):73-6. PubMed Wilson PW, D'Agostino RB, Levy D, Belanger AM, Silbershatz H, Kannel WB. Prediction of coronary heart disease using risk factor categories. Circulation 1998 May 12;97(18):1837-47. PubMed |
The National Heart, Lung, and Blood Institute (NHLBI) and the Veterans Health Administration, Department of Defense (VHA/DoD) present recommendations for screening for high cholesterol among adults for primary prevention of CHD and ASCVD. The guidelines also contain recommendations for clinical management of high blood cholesterol and secondary prevention in patients with existing CHD or ASCVD; these topics, however, are beyond the scope of this synthesis.
The guidelines describe the clinical evidence and give explicit reasoning for their recommendations. VHA/DoD presents its guideline in algorithmic form, with accompanying objectives, direct recommendations, and discussions that expand on the statements found in each box of the algorithm. A review of the evidence is included in the discussions, and a more detailed comprehensive summary of major recent studies is also provided in the appendices of the guideline. The NHLBI guideline and addendum contain both detailed discussions of the clinical evidence and summary algorithms. NHLBI provides graded evidence statements in the original guideline document. Both guidelines grade the evidence supporting their recommendations using a pre-specified rating scheme.
There is agreement between the guidelines that initial screening should be a fasting lipid profile, which includes measurement of TC, TG, HDL-C, and LDL-C (direct or calculated), in preference to the nonfasting tests.
The classification scheme of total, LDL-C and HDL-C levels used by VHA/DoD is derived from, and thus in agreement with, the NHLBI ATP II/ATP III guidelines. A total cholesterol concentration <200 mg/dL represents a "normal" or "desirable" blood cholesterol level; a concentration between 200 and 239 mg/dL is "borderline high," and >240 mg/dL is "high." Critical values for LDL-C are 130 to 159 mg/dL (borderline high) and >160 mg/dL (high-risk). HDL-cholesterol levels are considered optimal at >60 mg/dL, while HDL-C levels below 40 mg/dL will place patients at high risk for CHD. ATP III specifically states that "low" HDL-cholesterol should be defined as <40 mg/dL because this is a better measure of depressed HDL than <35 mg/dL.
There is general agreement between both guideline groups that any further management decisions should be based on CHD risk assessment as well as results of lipid screening. The core set of risk factors (excluding LDL-cholesterol) for CHD includes advanced age, hypertension, obesity, family history of CHD, cigarette smoking, diabetes mellitus type II, and low HDL-cholesterol levels. Both NHLBI and VHA/DoD go a step beyond simple counting of risk factors by recommending use of Framingham projections of 10-year absolute CHD risk to identify certain patients with >2 risk factors for more intensive treatment. The use of the Framingham model in risk assessment is a change from the previous (1999) version of the VHA/DoD guideline. Both guidelines also recommend that secondary causes of dyslipidemia, such as diabetes mellitus, obstructive liver disease, hypothyroidism, use of certain drugs, and ethanol use, need to be investigated and addressed before initiation of lipid-lowering therapy.
The two guidelines differ somewhat in their LDL goals for patients in the various risk groups. With the 2004 addendum, NHLBI modified their recommendations for initiation of TLC and drug therapy. This is discussed further under areas of disagreement.
The guidelines advocate repeated screening at least once every five years in persons with no or low risk factors for CHD. Depending on the results of the initial lipid screen, testing may occur more frequently. In addition, testing should occur more often in persons whose TC approaches a threshold for initiating treatment.
While both groups included in this synthesis recognize that low HDL-C is a strong independent predictor of CHD, neither of them specifically recommends treating low HDL-C nor do they specify a goal for raising HDL. NHLBI reports there is insufficient evidence to specify such a goal and also notes the lack of available drugs for treating low HDL-C. Both NHLBI and VHA/DoD instead focus on LDL-cholesterol as the primary target of therapy.
Who should be screened for dyslipidemia is the major area of disagreement between the two guideline groups. NHLBI recommends lipid screening for all individuals starting at 20 years of age, based on evidence that CHD disease develops in a continuous fashion, often beginning in the early twenties. They also argue that early awareness may encourage healthy behaviors. Furthermore, waiting until age 35 in men and age 45 in women may result in missed opportunities for early intervention. VHA/DoD, on the other hand, does not recommend screening before age 35 for men and before age 45 for women unless the individuals have one or more risk factors for CHD or a history suggestive of familial hyperlipidemia. VHA/DoD presents evidence that the short-term risk for developing CHD is low in these groups, even among those with an elevated cholesterol level, and the potential benefits of cholesterol reduction are small and thus not cost-effective. Neither of the guidelines identified randomized clinical trials that provided direct evidence on the effects of cholesterol reduction in these age groups.
NHLBI does not indicate an upper age limit for lipid screening and maintains that age alone should not be reason to withhold the benefits of cholesterol lowering. VHA/DoD, on the other hand, suggests an upper age limit of 75 years for testing, based on a lack of benefit of treatment in this age group.
Recent statin trials have provided new information on benefits of LDL-lowering therapy applied to persons in categories in which ATP III could not make definitive recommendations about drug therapy. To this point, the 2004 NHLBI guideline addendum has issued modified LDL-C goals and cutpoints for initiation of therapeutic lifestyle changes and drug therapy. These changes include the expansion of risk categories from 3 to 4 defined as:
TLC is recommended in high-risk patients whenever the LDL-C level is >100 mg/dL. Furthermore, any person at high risk who has lifestyle-related risk factors (e.g., obesity, physical inactivity, elevated triglycerides, low HDL-C, or metabolic syndrome) is a candidate for TLC to modify these risk factors regardless of LDL-C level. As before, whenever the baseline LDL-C concentration is >130 mg/dL, simultaneous initiation of an LDL-lowering drug and dietary therapy is recommended. If LDL-C is 100 to 129 mg/dL, the same now holds. If baseline LDL-C is <100 mg/dL and the patient is considered to be at very high risk, initiation of an LDL-lowering drug to achieve an LDL-C level of <70 mg/dL is a therapeutic option that has clinical trial support. For those high risk patients who have elevated triglycerides or low HDL-C levels, addition of a fibrate or nicotinic acid to LDL-lowering therapy can be considered.
For patients at moderately high risk (10-year risk 10% to 20%), the LDL-C goal remains <130 mg/dL. However, a goal of <100 mg/dL represents a therapeutic option on the basis of evidence of efficacy in risk reduction from primary prevention trials. TLC should be initiated in all such persons whose LDL-C level is >130 mg/dL. Again, any person at moderately high risk who has lifestyle-related risk factors (e.g., obesity, physical inactivity, elevated triglycerides, low HDL-C, or metabolic syndrome) is a candidate for TLC to modify these risk factors regardless of LDL-C level. If the LDL-C concentration is >130 mg/dL after TLC, consideration should be given to initiating an LDL-lowering drug, to achieve and sustain the LDL-C goal of <130 mg/dL. For LDL-C levels of 100 to 129 mg/dL at baseline or on lifestyle therapy, initiation of an LDL-lowering drug to achieve an LDL-C level <100 mg/dL is a therapeutic option on the basis of clinical trial evidence of additional efficacy.
The lipid goals and therapies for primary prevention recommended by VHA/DoD parallel those of the NHLBI guidelines in most respects. The major difference is that VHA/DoD states that an LDL-C reduction of 30 to 40% from baseline may be considered an alternative therapeutic strategy in patients unable to meet the prescribed goals. VHA/DoD's rationale is that in patients with a high LDL at baseline, the full risk-benefit of combination drug therapy or high-dose statin therapy is unknown, particularly in patients with comorbid diseases or those taking concomitant drugs. They cite data from meta-analyses of major statin randomized controlled trials to support this option.
This Synthesis was prepared by NGC on July 28, 2000. It was reviewed by the guideline developers as of October 10, 2000. It has been modified a number of times. The most recent version updates the VHA/DoD guidelines.
Internet citation: National Guideline Clearinghouse (NGC). Guideline synthesis: Lipid screening in adults and children. In: National Guideline Clearinghouse (NGC) [website]. Rockville (MD): 2000 Oct 10. (updated 2006 Jan) [cited YYYY Mon DD]. Available: http://www.guideline.gov.