The recommendations for the management of dyslipidemia in the primary care setting are organized into 3 major algorithms. Each algorithm, the objectives and annotations that accompany it, and the evidence supporting the recommendations are presented below. The strength of recommendation grading (A-E) and quality of evidence grading (I-III) are defined at the end of the "Major Recommendations" field.
- Adult Patient Enrolled in the Health Care System
Definition
Any Adult (> age 17) who is eligible for care in the Department of Defense (DoD) or Veterans Health Administration (VHA) health care delivery system should be screened for dyslipidemia as described in this guideline.
- Obtain History. Assess Risk Factors for Atherosclerotic Cardiovascular Disease (ASCVD)
Objective
To identify clinical markers that predict an increased risk for developing ASCVD, thereby changing the interpretation of LDL levels.
Annotation
A high low-density lipoprotein (LDL) cholesterol level is a strong predictor of cardiovascular (CV) risk, although in the absence of other CV risk factors the absolute risk for developing ASCVD is still relatively low. Conversely, the presence of other recognized coronary heart disease (CHD) risk factors magnify the risk associated with any level of LDL. Proven, independent, clinical predictors of increased risk for ASCVD (in addition to elevated LDL cholesterol) include:
- Age (males > 45 years, females > 55 years or
menopause < age 40?)
- Family history of premature coronary artery
disease; definite myocardial infarction (MI) or sudden death before age 55
in father or other male first-degree relative, or before age 65 in mother or
other female first-degree relative
- Current cigarette smoker
- Hypertension (systolic blood pressure > 140 mmHg or diastolic blood pressure > 90 mmHg confirmed on more than one occasion,
or current therapy with antihypertensive medications)
- Diabetes mellitus (DM)
- High-density lipoprotein (HDL)-cholesterol < 40 mg/dL
"Negative" Risk Factor
Elevated HDL cholesterol, > 60 mg/dL, is a well-established independent, clinical predictor of decreased risk for ASCVD. It has been suggested that an HDL > 60 mg/dL negates one ASCVD risk factor for individual risk calculation.
Evidence
LDL:
Quality of Evidence=I; Strength of Recommendation=A (Multiple Risk Factor Intervention Trial [MRFIT], 1982; Neaton & Wentworth, 1992; Castelli, 1984).
HDL: Quality of Evidence=II-2; Strength of Recommendation=A (Gordon, Probstfeld, & Garrison, 1989; Downs et al., 1998; Wilson, Abbott, & Castelli, 1988; Kannel, 1978).
- Does Patient Have a History of ASCVD?
Objective
Prompt identification of patients known to benefit from lipid lowering therapy.
Annotation
All patients with known CHD (history of myocardial infarction [MI], angina pectoris, other evidence of CHD) or a history of other kinds of vascular disease (such as stroke or claudication) are at high risk for coronary events. Prevention of recurrent and fatal coronary events via aggressive lipid-lowering therapy has been demonstrated in large clinical trials.
- Is Patient Younger than 35 Years or Older than 75 Years?
Objective
To screen the segment of the beneficiary population most represented in randomized controlled trials of hyperlipidemia intervention.
Annotation
At a population level, patients of any age may benefit from general lifestyle recommendations to curtail dietary saturated fat and to perform aerobic exercise several times per week, regardless of the results of lipid screening. Targeted lipid screening of males aged 35 to 75 years and females aged 45 to 75 years is recommended in the primary prevention setting, based on the results of RCTs of lipid interventions. For every given age, the ASCVD risk for a female is the same as that for a male 10 years her junior.
The recommendation for screening up to age 65 is based on strong clinical and epidemiologic evidence. The recent AFCAPS/TexCAPS (Air Force/Texas Coronary Atherosclerosis Prevention Study) trial results (Downs et al., 1998) suggest that treating patients age 65-73 is beneficial. Epidemiologic evidence suggests benefit in ages 65 to 75. The association of cholesterol and mortality weakens in elderly patients, and screening is not recommended for primary prevention after age 75.
The risk of ASCVD is so low in males younger than 35 years and females younger than 45 years that screening cannot be recommended unless there is an unusual family history of coronary events occurring prior to age 45.
- Provide Age-Appropriate Lifestyle Education on Smoking, Diet, and Exercise
Objective
To promote lifestyle changes that will decrease the risk of ASCVD.
Annotation
Smoking, diet, and activity level are important modifiable predictors of risk for ASCVD (McGinnis & Foege, 1993). Primary care clinicians can have a positive effect on health behaviors and should provide and/or arrange for age-appropriate lifestyle education. The top three lifestyle behaviors associated with premature death are:
Risk: Smoking
Recommended Intervention: Advise smokers/tobacco users to quit.
Risk: Diet
Recommended Intervention: Provide basic information about managing a healthy diet (using the U.S. Department of Agriculture Dietary Guidelines for Americans, 1992).
Risk: Sedentary lifestyle
Recommended Intervention: Encourage 30 minutes or more of moderate intensity activity on most days of the week.
Many experts also recommend attention to the following additional lifestyle modifications:
- Limitation of alcohol intake to one or two drinks
per day
- Reduced calorie diet to promote weight loss, if
overweight
- Stress management
Evidence
Smoking: Quality of Evidence=I; Strength of Recommendation=A (U.S. Department of Health and Human Services [USDHHS], 1989; National Cancer Institute [NCI], 1994; Ockene, 1987; Ockene et al., 1991; Fiore, 1994).
Diet: Quality of Evidence=I; Strength of Recommendation=A (U.S. Preventive Services Task Force [USPSTF], 1996; Beresford et al., 1997; McCarron et al., 1997).
Exercise: Quality of Evidence=I; Strength of Recommendation=A (Pate et al., 1995; American College of Sports Medicine [ACSM], 1995; Pollock & Wilmore, 1990; Spate-Douglas & Keyser, 1999).
Lifestyle changes promote general health: Quality of Evidence=III; Strength of Recommendation=A (Executive Summary of the third report of the National Cholesterol Education Program [NCEP III], 2001).
Changing behavior is very difficult: Quality of Evidence=I; Strength of Recommendation=A (Ebrahim, Davey, & Smith, 1999).
- Does Patient Have Diabetes Mellitus?
Objective
To promote the prompt identification and aggressive management of lipid disorders identified in patients known to be diabetic.
Annotation
- Patients with DM are at significantly increased
risk of CHD compared with non-diabetic patients of similar age.
- DM patients without known CHD appear to have a risk
for first MI similar to the risk for recurrent MI of non-DM patients with
CHD and a prior coronary event.
- Patients with type 2 diabetes commonly have other risk factors (hypertension, high LDL-C, low HDL-C, obesity) that increase risk for cardiac events.
Evidence
Diabetes is an independent risk factor: Quality of Evidence=II-2; Strength of Recommendation=B (MRFIT, 1982; Neaton & Wentworth, 1992; Stamler et al., 1993; Haffner et al., 1998).
Management of "diabetic dyslipidemia": Quality of Evidence=I; Strength of Recommendation=A (Rubins et al., 1999).
- Obtain Total Cholesterol (TC) and HDL or TC, HDL, TG, LDL
Objective
To risk-stratify patients for targeted intervention versus follow-up screening.
Annotation
Lipid levels may be obtained in a fasting or nonfasting state. TC levels and HDL-C can be measured in the nonfasting patient. TG concentrations, however, are affected by recent food intake and will affect the calculation of LDL-C by the Friedewald equation: LDL-C = [TC] - [HDL-C] - [TG/5].
Nonfasting values differ from fasting values, but may still provide useful-though more limited-information. It may be inconvenient for the patient to return for a fasting sample. Costs may vary depending on which lipids (TC, HDL, LDL, VLDL, TG) are requested. At many institutions, a panel is available.
Clinical decisions should be based on two lipid profiles, done 1 to 8 weeks apart, which have an LDL-C or TC difference of < 30 mg/dL.
Recent myocardial infarction, stroke, surgery, trauma, or infection may transiently lower cholesterol levels up to 40 percent. If a lipid profile cannot be obtained immediately (within 12 to 24 hours of the event), one must wait 8 weeks post-event to obtain an accurate reading. Cholesterol levels increase by as much as 20 to 35 percent during pregnancy and should not be measured until three to four months after delivery.
- Reinforce Lifestyle Education, Smoking, Diet, and Exercise
Refer to Annotation E.
- Repeat Dyslipidemia Evaluation in 1 to 5 Years
Objective
To provide appropriate clinical follow-up for patients at initially low risk for ASCVD.
Annotation
If the initial dyslipidemia screening reveals total cholesterol < 200 mg/dL or LDL cholesterol < 130 mg/dL AND HDL cholesterol > 35 mg/dl, the patient-in the absence of other risk factors-will be of average or below average risk for atherosclerotic events over a five-year period.
Because total and LDL cholesterol tend to increase with advancing age, patients at initially average risk for ASCVD events may over time become patients at above-average risk or may develop concurrent health conditions (nephrotic syndrome, hypothyroidism, diabetes mellitus) that can declare as dyslipidemia. Re-assessment of serum cholesterol and HDL five years after an initially favorable dyslipidemia screening permits timely identification and treatment of such individuals.
Evidence
Appropriate follow-up:
Quality of Evidence=III; Strength of Recommendation=A (NCEP III, 2001; Lovastatin Study Groups, 1993; Jones et al., 1991).
- Is Lipid Profile Abnormal?
Objective
To identify a group of patients who require further evaluation and/or therapy for hyperlipidemia.
Annotation
Patients with the following results of lipid measurements will require therapy for a lipid disorder:
- LDL > 130 mg/dL
- HDL < 40 mg/dL
- TG > 400 mg/dL
- Repeat Dyslipidemia Evaluation in 1 to 2 Years
Objective
To provide appropriate clinical follow-up.
Annotation
If the initial dyslipidemia screening reveals total cholesterol > 200 mg/dL but fasting LDL cholesterol < 130 mg/dL AND HDL cholesterol > 40 mg/dL, the patient will be of average risk for lipid-related events over a one to two year period.
- Evidence of Familial Disorder that Complicates Treatment?
Objective
To promote the prompt identification and aggressive lipid management that is indicated for this group.
Annotation
Most severe forms of hypercholesterolemia are the result of genetic disorders. Familial hypercholesterolemia is characterized by severe elevations of LDL cholesterol (> 260 mg/dL), tendon xanthomas, and premature CHD. Familial combined hyperlipidemia is characterized by elevations of total cholesterol, triglycerides, or both, in different members of the same family, and is associated with premature CHD. Patients presenting with very severe hypercholesterolemia should undergo family screening to detect other candidates for therapy. Therefore, a consultation with a specialist is recommended to assist the primary care clinician in co-managing these patients.
- Consider and Treat Secondary Causes of Elevated LDL-C
Objective
To detect and, if needed, to treat health disorders that present as an elevated LDL-C.
Note: If a patient has hypertriglyceridemia, see Annotation N.
Annotation
Hypothyroidism, chronic renal failure, and the nephrotic syndrome are well known to cause elevated LDL-C. Recognition of these conditions will focus attention on a potentially treatable underlying disorder. Cost-effective screening of the patient presenting with hypercholesterolemia might therefore include measurement of serum thyroid-stimulating hormone (TSH), BUN/creatinine, and a dipstick urinalysis, to exclude these relatively common conditions. See Table 1 titled "Address Secondary Causes of Lipid Abnormalities" in the original guideline for the effects of various disorders of lipid levels and suggested laboratory tests for diagnosis of these disorders.
Evidence
Address secondary causes: Quality of Evidence=III; Strength of Recommendation=A (Stone, 1997; NCEP III, 2001).
- Consider and Treat Secondary Causes of Hypertriglyceridemia
Objective
To identify and address the secondary causes of hypertriglyceridemia.
Note: If patient has elevated LDL, see Annotation M above.
Annotation
The most common secondary causes of hypertriglyceridemia are alcohol, diabetes, and hypothyroidism. Addressing these underlying conditions can improve or normalize triglyceride levels, and failure to address these can render therapy ineffective.
- Is TG > 400 mg/dL?
Objective
To identify patients for whom LDL-C calculation is not reliable.
Annotation
The Friedwald LDL calculation [LDL-C = total cholesterol - (HDL-C + TG/5)] yields unacceptably inaccurate estimation of the LDL cholesterol in patients with triglycerides > 400. There are other means to measure atherogenic cholesterol in this setting. Non-HDL cholesterol can be estimated using the simple formula [Non-HDL cholesterol = Total cholesterol - HDL] or by direct measurement of the LDL.
- Is TG > 1000 mg/dL? Evaluate and Treat as Indicated
Objective
To identify and treat patients with extreme levels of triglycerides.
Annotation
Patients with triglycerides >1,000 are at increased risk of pancreatitis.
Treatment of Hypertriglyceridemia (TG >1000 mg/dL)
First Choice: Fibrates
Alternative: Niacin
Remarks: Fibrates are contraindicated in severe renal disease. Niacin is contraindicated in hepatic disease and relatively contraindicated in DM, gout, and history of complicated/active peptic ulcer disease (PUD).
Evidence
Treat extreme levels of triglycerides: Quality of Evidence=III; Strength of Recommendation=A (Piolot et al., 1996; NCEP III, 2001).
- Initiate Medical Nutrition Therapy (MNT) and Exercise
Objective
To reduce TG level with non-pharmacological therapy.
Annotation
For those individuals with elevated TG, the clinician should initiate MNT and appropriate exercise program. See Appendix 1, MNT, and Appendix 2, Exercise, of the original guideline document.
Evidence
MNT: Quality of Evidence=III; Strength of Recommendation=A (National Institutes of Health [NIH] Consensus Conference, 1993).
Exercise: Quality of Evidence=III; Strength of Recommendation=A (NIH Consensus Conference, 1993; Pate et al., 1995; Joint British recommendations, 1998).
- Is LDL-C > 160 mg/dL (Estimated Non-HDL-C > 190)?
Objective
To identify patients who may need therapy for hypercholesterolemia.
Annotation
Patients with LDL cholesterol > 130 who have two or more atherosclerotic risk factors (other than cholesterol) or diabetes mellitus have significant risk of coronary or peripheral vascular events. Multiple prospective intervention trials have consistently demonstrated reduction in atherosclerotic event rates with treatment of hypercholesterolemia. In patients with known CHD (secondary prevention), the reduction in clinical endpoints is particularly compelling based on the demonstration of mortality benefit in some studies.
Evidence
LDL > 160 (Primary Prevention): Quality of Evidence=I; Strength of Recommendation=A (Downs et al., 1998; Frick et al., 1987; Lipid Research Clinics Program, 1984; Shepherd et al., 1995; NCEP III, 2001).
- Determine Goal of Therapy; Initiate/Modify Therapy to Achieve Goal
Objective
To select an appropriate therapy based on LDL-C baseline level and other risk factors for ASCVD.
- Select an appropriate LDL-C target
- Initiate nonpharmacologic therapy
- For patients who do not reach LDL target, initiate pharmacotherapy.
Annotation
Treatment should be based on LDL-C and CHD risk. CHD risk factors are age, family history, current smoker, hypertension, diabetes, and HDL-C < 40 mg/dL. Patients with CHD or multiple risk factors require more aggressive treatment. The goals for therapy and treatment are summarized below and in Table 3a and 3b in the original guideline document.
LDL-C Thresholds for Initial Dyslipidemia Treatment Based on Risk for ASCVD (Note: If one risk factor is diabetes, the diabetes category is used to determine threshold and category)
Known CHD
Baseline LDL-C [mg/dL] > 100: Diet/exercise; consider drug
Baseline LDL-C [mg/dL] > 130: Diet/exercise + drug
Baseline LDL-C [mg/dL] > 160: Diet/exercise + drug
Baseline LDL-C [mg/dL] > 190: Diet/exercise + drug
Diabetes (without known CHD)
Baseline LDL-C [mg/dL] > 100: Diet/exercise; consider drug
Baseline LDL-C [mg/dL] > 130: Diet/exercise + drug
Baseline LDL-C [mg/dL] > 160: Diet/exercise + drug
Baseline LDL-C [mg/dL] > 190: Diet/exercise + drug
No known CHD but > 2 risk factors
Baseline LDL-C [mg/dL] > 100: No treatment
Baseline LDL-C [mg/dL] > 130: Diet/exercise
Baseline LDL-C [mg/dL] > 160: Diet/exercise + drug
Baseline LDL-C [mg/dL] > 190: Diet/exercise + drug
No known CHD but < 2 risk factors
Baseline LDL-C [mg/dL] > 100: No treatment
Baseline LDL-C [mg/dL] > 130: No treatment
Baseline LDL-C [mg/dL] > 160: Diet/exercise
Baseline LDL-C [mg/dL] > 190: Diet/exercise + drug
LDL-Cholesterol Goals in the Treatment of Dyslipidemia Based on Risk for ASCVD
Known CHD: <120 mg/dL*
Diabetes (without known CHD): <120 mg/dL*
No known CHD, but > 2 risk factors: <130 mg/dL
No known CHD, but < 2 risk factors: <160 mg/dL
*NCEP III recommends an LDL-C goal of < 100 mg/dL in patients with known CHD and CHD equivalents (i.e., type 2 diabetes mellitus)
Non-Pharmacologic Therapy
Lifestyle change is indicated in all patients with 2 risk factors and LDL > 130mg/dL (> 100 mg/dL for known CHD or diabetes). Strategies include diet, exercise, smoking cessation, cessation of excessive alcohol, and weight control.
For primary prevention of ASCVD, patients whose initial treatment is diet/exercise should be given three to six months on dietary therapy prior to beginning medication, and longer if lipids are improving and nearing LDL thresholds. Patients failing clinician-initiated efforts may benefit from a MNT consult prior to initiating medications (See Appendix 1 titled "Medical Nutrition Therapy" of the original guideline document). The expected response to diet therapy is summarized below and in Table 4 of the original guideline. For secondary prevention of recurrent ASCVD events, non-pharmacologic therapy is always indicated, but should not delay appropriate pharmacotherapy.
Expected Percent Change in Serum Lipids in Response to Diet Therapy
LDL
Step I Diet -- -5 to -20%
Step II Diet -- -10 to -25%
Very Low Fat -- -0 to -20%
High MUFAa -- -5 to -20%
TG
Step I Diet -- +5 to -10%
Step II Diet -- +10 to -10%
Very Low Fat -- Decrease with weight loss; increase without weight loss
High MUFAa -- No change or slight decrease
aMUFA = Monounsaturated fatty acids.
Pharmacologic Therapy
Drug therapy is indicated in CHD/ASCVD patients and moderate-high risk primary prevention patients who remain above LDL thresholds with non-pharmacologic measures. HMG-CoA reductase inhibitors (statins) are first line agents in most situations. They are cost-effective in secondary prevention and high-risk primary prevention risk groups. The dose should be adjusted at 4 to 6 week intervals until the individually-determined LDL-C goals are met. Other agents have been shown to reduce CHD events and angiographic progression, but have had minimal impact on total mortality. The first line drugs and alternatives for lipid disorders are summarized below and in Table 5 of the original guideline document.
Dyslipidemia Drug Therapy Recommendations Based on Lipid Disorder
Lipid Disorder: Elevated LDL-C
Initial monotherapy: Statins
Efficacy: LDL -22 to -60%
Considerations: Caution using statins in hepatic disease
Alternate monotherapy: Niacin
Efficacy: LDL -13 to -21%
Considerations: Niacin is contraindicated in hepatic disease and relatively contraindicated in DM, gout, and history of complicated/active PUD;
Alternate monotherapy: Bile acid resin (resin)
Efficacy: LDL -10 to -20%
Considerations: Resins may increase TG
Lipid Disorder: Elevated LDL-C and Elevated TG
Initial monotherapy: Niacin
Efficacy: LDL -13 to -21%; TG -10 to -24%
or
Initial monotherapy: Statin
Efficacy: LDL -22 to -60%; TG -06 to -37%
Alternate monotherapy: Fibrates
Efficacy: LDL +10 to -35%; TG -32 to -53%
Considerations: For high TG, use fibrates or niacin; for high LDL, use statins
Lipid Disorder: Elevated LDL and Decreased HDL
Initial monotherapy: Niacin
Efficacy: LDL -13 to -21%; HDL +10 to +24%
or
Initial monotherapy: Statin
Efficacy: LDL -22 to -60%; HDL +2 to +12%
or
Initial monotherapy: Fibrates
Efficacy: LDL +10 to -35%; HDL +2 to +34%
Considerations: No preferences in terms of efficacy
Lipid Disorder: TG 400-1000 mg/dL
Consider gemfibrozil if HDL-C < 40 mg/dL
For high TG, use direct LDL-C measurement or non-HDL-C as lipid disorder to guide therapy
For CHD/ASCVD Patients
For patients with known CHD/ASCVD who have HDL < 40 mg/dL pharmacotherapy with gemfibrozil is recommended:
LDL-C < 130 mg/dL and HDL-C < 40 mg/dL
Efficacy: LDL +10 to -35%; HDL +2 to 34%
Considerations:
Outcome data for secondary prevention only
Evidence
Lifestyle education:
Quality of Evidence=I; Strength of Recommendation=A (Wilson et al., 1998; Ebrahim, Davey, & Smith, 1999).
Primary prevention: Quality of Evidence=I; Strength of Recommendation=A (Downs et al., 1998; Shepherd et al., 1995).
Secondary prevention:
Quality of Evidence=I; Strength of Recommendation=A (Scandinavian Simvastatin Survival Study Group (4S), 1994; Leng, Price, & Jepson, 1999; NCEP III, 2001; Sacks et al., 1996; Frick et al., 1987; Canner et al., 1986; Post Coronary Artery Bypass Graft [CABG] Trial Investigators, 1997).
Treatment of low HDL:
Quality of Evidence=1; Strength of Recommendation=A (Gordon, Probstfeld, & Garrison, 1989; Rubins et al., 1999).
- Follow Up, Repeat Lipid Evaluation at Least Annually
Objective
To assure that patients initially treated for dyslipidemia receive periodic reassessment of the efficacy of treatment.
Annotation
When dyslipidemia is identified and the care provider and patient undertake dietary and/or pharmacologic treatment, it is pertinent clinically and economically to periodically repeat measurement of serum lipids to ensure that initially desirable response to therapy continues. Total and LDL cholesterol tend to increase with advancing age, even in intensively treated patients. Thus, an initially favorable response to treatment may not be maintained over time.
Evidence
Periodic follow up:
Quality of Evidence=III; Strength of Recommendation=B (NCEP III, 2001).
- Address Adherence to Therapy
Objective
To address patient adherence to diet, exercise, and drug therapy.
Annotation
Patients should be questioned about adherence to treatment at each visit. A minimum of three to six months of intensive diet and exercise is recommended before medications are initiated for primary prevention. Shorter trials of MNT and exercise are appropriate for patients with severe hyperlipidemia or ASCVD, since aggressive drug therapy is of demonstrated efficacy in these high risk groups.
Reasons for medication noncompliance include the following:
- Medication side effects: Particularly an issue for
niacin and resins, although statins may cause myalgias and nonspecific
gastrointestinal symptoms.
- Incomplete patient education: Patients may not
understand benefit of medication or need for long-term therapy.
- Cost: Patients may not be able to afford medications.
Reasons for diet and exercise noncompliance include the following:
- Incomplete patient effort and self-motivation: Some
patients are unable or unwilling to comply with strict dietary changes, such
as a Step II diet, and a regular exercise regimen.
- Suboptimal social support: Family and lifestyle may
not be conducive to strict dietary changes. Patients may not have access to
exercise facilities or safe environment (e.g., safe neighborhood in which to
walk).
- Incomplete patient education: Some patients may not
have received adequate information because of missed visits or inadequate
time for counseling.
- Cost: Patients may perceive that dietary interventions increase costs, though this is generally not the case. Patients unable to walk may not have access to other exercise options (swimming, stationary bike/machines, etc.).
- Modify Drug Therapy; Consider Combination Therapy
Objective
To modify drug therapy to achieve LDL-C goal.
Annotation
Niacin and resins are considered alternative therapy in patients who do not tolerate initial therapy. If the patient has not achieved the LDL-C goal with initial therapy, consider the addition of a second agent. Clinical judgment must be used to balance patient issues, side effects, and monitoring parameters.
- Reschedule Lipids Evaluation at Appropriate Time and Follow Up until Goal Met
Objective
To assure that the efficacy of prescribed therapy of hyperlipidemia is measured after allowing sufficient time to reach a new steady state.
Annotation
Nadir values of LDL cholesterol and triglycerides may not be achieved until after three to six months on a Step I or Step II diet. Pharmacotherapy likewise may not result in lower lipid values until after at least one month of treatment. Remeasurement of serum lipids after at least one month of drug therapy, or after at least three months of dietary therapy, allows for the documentation of efficacy, the identification of unfavorable effects of treatment, and the dose titration of medication.
- Is LDL-C > 130 mg/dL or HDL-C < 40 mg/dL?
Objective
To identify patients with ASCVD who are candidates for aggressive treatment of hypercholesterolemia.
Annotation
Patients with known ASCVD (secondary prevention) have significant risk of coronary or peripheral vascular events and are therefore candidates for aggressive lipid management. Multiple prospective intervention trials have consistently demonstrated reduction in atherosclerotic event rates with treatment of hypercholesterolemia. For this group, the reduction in clinical endpoints is particularly compelling, based on the demonstration of mortality benefit in some studies. In the major clinical trials published to date, actual LDL-C attained with statin therapy has ranged between 98 mg/dL and 118 mg/dL. As noted above and in Table 3 of the original guideline document, the target lipid levels in secondary CHD prevention are:
- LDL-C < 120 mg/dL* and
- HDL-C > 40 mg/dL.
*NCEP III and the American Diabetes Association guidelines support initiation of LDL-lowering therapy for patients with LDL in the 100-130 mg/dL range. Absolute risk reduction in CHD events for drug treatment initiated at this threshold has not yet been established, except in the setting of HDL-C < 40 mg/dL (VA-HIT Study, 1999).
In the VA-HIT Study, the average LDL-C of treated patients was 112 mg/dL and the average HDL-C was 33 mg/dL.
Evidence
Aggressive treatment for patients with known ASCVD: Quality of Evidence=I; Strength of Recommendation=A (Post CABG Trial Investigators, 1997; Sacks et al., 1996; Long-Term Intervention with Pravastatin in Ischemic Disease Study Group [LIPID], 1998; Rubins et al., 1999).
- Repeat Evaluation in 1 to 2 Years as Indicated
Objective
To assure that patients with CAD risk factors other than hyperlipidemia are carefully monitored for onset of hyperlipidemia.
Annotation
Because total and LDL cholesterol tend to increase with advancing age, patients with initially borderline LDL values may evolve frankly elevated LDL with the passage of 1 year, or may develop concurrent health conditions (nephrotic syndrome, hypothyroidism, diabetes mellitus) that can declare as hyperlipidemia. Patients known to be at high risk for CAD based on multiple risk factors other than hyperlipidemia are candidates for early and aggressive dietary and pharmacologic therapy; thus annual reevaluation of serum lipid status is prudent and cost-effective.
I: Evidence obtained from at least one properly designed randomized controlled trial.
II-1: Evidence obtained from well-designed controlled trials without randomization
II-2: Evidence obtained from well-designed cohort or case-control analytical studies, preferably from more than one center or research group.
II-3: Evidence obtained from multiple time series with or without the intervention. Dramatic results in uncontrolled experiments (such as the results of the introduction of penicillin treatment in the 1940s) could also be regarded as this type of evidence.
III: Opinions of respected authorities, based on clinical experience; descriptive studies and case reports; or reports of expert committees.
