Lack of concordance in classification of coronary heart disease risk: high-risk HDL cholesterol less than 35 mg/dl in subjects with desirable total serum cholesterol, less than 200 mg/dl

In using National Cholesterol Education Program guidelines (for desirable low risk, a total cholesterol level less than 200 mg/dl, and for high risk, a level of high-density lipoprotein cholesterol (HDLC) less than 35 mg/dl), our specific aim was to examine lack of concordance in classification of coronary heart disease (CHD) risk by HDLC less than 35 mg/dl in subjects with total cholesterol less than 200 and to determine whether lack of concordance increased as group CHD risk increased. We studied four cohorts ranging from putatively low to high CHD risk. These included self-referred subjects in a public urban total cholesterol screening (n = 897), hospitalized patients with depression (n = 144), Cholesterol Center referrals at presumed high CHD risk (n = 1120), and patients having coronary arteriography (n = 145) because of presumed coronary artery disease. Total cholesterol was less than 200 mg/dl in 25% of subjects from the urban sampling, in 54% of hospitalized patients with depression, in 27% of Cholesterol Center referrals, and in 41% of those undergoing cardiac catheterization. In these four cohorts, of subjects with total cholesterol less than 200, 7%, 26%, 25%, and 48%, respectively, had HDLC less than 35 mg/dl. The likelihood of having total cholesterol less than 200 and HDLC less than 35 mg/dl was 1.7% in urban public subjects, 6.8% in Cholesterol Center referrals, 13.9% in depressed patients, and 20% in cardiac catheterization patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Estimation of cardiovascular risk: total cholesterol versus lipoprotein profile

Summary The complete lipoprotein profile is thought to give more information about the individual risk of coronary heart disease than total cholesterol alone. Although total cholesterol has a low sensitivity in the correct assessment of the risk of coronary heart disease, it may be of value in screening programs because of its low cost. In this study of 5,335 subjects, total cholesterol gave a different assessment of coronary heart disease risk (United States National Cholesterol Education Program guidelines) in 25% of subjects than the complete lipoprotein profile. Differences in risk assignment were mainly accounted for by high- and low-density lipoprotein-cholesterol (Friedewald equation). The calculated low-density lipoprotein-cholesterol was highly correlated with the value measured with a mixed ultracentrifugation and precipitation procedure. However, calculated values gave estimates of coronary heart disease risk which were 20% different from those from measure values. In 200 subjects in whom the lipoprotein profile was assessed three times in 1 year, the total cholesterol low-density lipoprotein-cholesterol varied by more than 30 mg/dl (0.78 mmol/l) in 52% and 50%, respectively, triglycerides by more than 30 mg/dl (0.34 mmol/l) in 75%, and high-density lipoprotein-cholesterol by more than 15 mg/dl (0.39 mmol/l) in 34%. Compared with the mean of the measurements, the single measurement of total cholesterol misclassified 48% of subjects, low-density lipoprotein-cholesterol 60%, high-density lipoprotein-cholesterol 12%, and 28%. We conclude that total cholesterol alone may be misleading in the assignment of coronary heart disease risk. Calculation of low-density lipoprotein-cholesterol, although less accurate than desirable, is the only way of evaluating this in clinical practice. Finally, repeated lipid measurements are required to assess coronary heart disease risk accurately.     

Regional interlaboratory standardization of determinations of cholesterol, high-density lipoprotein cholesterol, and triglycerides

The Clinical Chemistry Forum of Central Virginia initiated a lipid standardization program to help ensure that its members meet the current National Cholesterol Education Program guidelines for cholesterol testing, and to standardize assays of high-density lipoprotein (HDL) cholesterol and triglycerides so as to provide accurate lipid profiles. We found that freshly collected, never-frozen human sera must be used to assess interlaboratory accuracy for cholesterol, HDL cholesterol, and triglycerides assays, and that at least 23 samples are required to detect a 3% bias with 90% power when the between-laboratory imprecision (CV) is 3%. After recalibration, all 12 laboratories had a mean HDL cholesterol bias less than or equal to 5%, nine of 10 laboratories had a mean HDL cholesterol bias less than or equal to 40 mg/L for samples with values less than or equal to 570 mg/L, and 10 of 12 laboratories had a mean triglycerides bias less than or equal to 10% for fresh human sera split between participants and the Centers for Disease Control. Pools of frozen human sera were shown to have matrix biases greater than 3% for cholesterol in seven of 11 laboratories, and greater than 40 mg/L for HDL cholesterol in six of nine laboratories.     

Prevalence of hypercholesterolaemia and coronary heart disease risk factors among Southeast Asian refugees in a primary care clinic

The National Cholesterol Education Program's guidelines for the detection, evaluation, and treatment of high serum cholesterol in adults were employed in screening 155 Southeast Asian refugees in a primary care clinic in Seattle, Washington. In order to determine the need for a therapeutic intervention, information also was collected on the presence of other coronary heart disease (CHD) risk factors. Male gender (39%), cigarette smoking (27%) and hypertension (26%) were the most common CHD risk factors; diabetes mellitus, obesity, a family or prior history of CHD or cerebral/peripheral vascular disease were each noted in less than 10%. The mean serum total cholesterol was 194 mg/dl. Thirty–seven (24%) patients required further lipoprotein analysis based on cholesterol level, history of CHD and risk factors for CHD. Twenty–one (66%) of 32 patients who underwent lipoprotein analysis (14% of all patients) were candidates for a therapeutic intervention for hypercholesterolaemia. Additionally, 14 (44%) patients undergoing lipoprotein analysis had depressed high–density lipoprotein levels (< 35 mg/dl). We conclude that CHD risk factors including hypercholesterolaemia are common in Southeast Asian refugee clinic patients and that in many, a therapeutic intervention may well be justified. Southeast Asian refugees should be routinely screened for hypercholesterolaemia and other CHD risk factors in accordance with the National Cholesterol Education Program's guidelines.     

Cholesterol guidelines, lipoprotein cholesterol levels, and triglyceride levels: potential for misclassification of coronary heart disease risk

By using National Cholesterol Education Program guidelines for serum cholesterol (less than 200 mg/dl is designated "desirable," and 200 to 239 mg/dl is designated "borderline-high," and greater than or equal to 240 mg/dl is designated "high"), low-density and high-density lipoprotein (LDL, HDL) cholesterol levels and triglyceride levels were quantitated in 897 self-referred fasting subjects to assess the potential for coronary risk misclassification. With cholesterol less than 200 mg/dl, misclassification was arbitrarily identified by an LDL level greater than or equal to the 75th percentile, a triglyceride level greater than or equal to the 90th percentile, or an HDL level less than or equal to the 10th percentile. With the cholesterol level in the 200 to 239 mg/dl range, misclassification was identified by an LDL level greater than or equal to the 75th percentile, a triglyceride level greater than or equal to the 90th percentile, and an HDL level less than or equal to the 10th percentile or greater than or equal to the 90th percentile (or both). With a cholesterol level greater than or equal to 240 mg/dl, misclassification was identified by an HDL level less than or equal to the 10th percentile, or greater than or equal to the 90th percentile. With the cholesterol level less than 200 mg/dl, misclassification is rare, occurring in 14.5% of the subjects. With the cholesterol level in the 200 to 239 mg/dl range, and greater than or equal to 240 mg/dl, misclassification occurred in 46.7% and 17.6% of the subjects, respectively. The importance of routine lipoprotein analysis when the cholesterol level is greater than or equal to 240 mg/dl is emphasized by the finding that 65% of the subjects in this category had top quartile LDL levels, 8% had bottom decile HDL levels, and 30% had top decile triglyceride levels. To avoid misclassification, fasting HDL, LDL, and triglyceride levels should probably be measured in all subjects with screening cholesterol levels greater than or equal to 200. There is remarkably little misclassification with top quartile LDL or bottom decile HDL levels (or both) when the cholesterol level is less than 200 mg/dl.     

Measurement of cholesterol and other lipoprotein constituents in the clinical laboratory.

Measurements of lipids and lipoproteins in the clinical laboratory have become increasingly important because of their predictive association with cardiovascular diseases, especially coronary artery disease. The US National Institutes of Health-sponsored National Cholesterol Education Program and counterparts in other countries have developed national consensus guidelines for diagnosis and treatment of coronary artery disease which provide risk cut-points and define use of the lipid/lipoprotein analytes in case finding and therapy. Total and low density lipoprotein cholesterol and triglycerides are measured as positive risk factors and high density lipoprotein cholesterol as an inverse risk factor for coronary artery disease. A National Cholesterol Education Program-sponsored expert laboratory panel has developed guidelines for measurements with requisite analytical performance targets for total error and corresponding precision and bias. The US Centers for Disease Control and Prevention have established reference methods for total and high density lipoprotein cholesterol and for triglycerides, with a method for low density lipoprotein cholesterol in development. Standardization programs for research laboratories and a Cholesterol Reference Method Laboratory Network for diagnostic manufacturers and clinical laboratories provide reliable access and documentation of traceability to accepted reference methods. Methods for the lipid/lipoprotein analytes have improved dramatically in recent years and, coupled with improved chemistry analyzer systems and more attention to standardization by manufacturers, offer considerable improvement in analytical performance. Fully automated homogeneous assays for high density lipoprotein cholesterol and newer similar assays for low-density lipoprotein cholesterol have potential for better precision as well as more convenient and cost-effective measurements. Attention to pre-analytical sources of variation is also important in making reliable classification of patients.     

Cholesterol treatment guidelines update

Hypercholesterolemia is one of the major contributors to atherosclerosis and coronary heart disease in our society. The National Cholesterol Education Program of the National Institutes of Health has created a set of guidelines that standardize the clinical assessment and management of hypercholesterolemia for practicing physicians and other professionals in the medical community. In May 2001, the National Cholesterol Education Program released its third set of guidelines, reflecting changes in cholesterol management since their previous report in 1993. In addition to modifying current strategies of risk assessment, the new guidelines stress the importance of an aggressive therapeutic approach in the management of hypercholesterolemia. The major risk factors that modify low-density lipoprotein goals include age, smoking status, hypertension, high-density lipoprotein levels, and family history. The concept of "CHD equivalent" is introduced-conditions requiring the same vigilance used in patients with coronary heart disease. Patients with diabetes and those with a 10-year cardiac event risk of 20 percent or greater are considered CHD equivalents. Once low-density lipoprotein cholesterol is at an accepted level, physicians are advised to address the metabolic syndrome and hypertriglyceridemia.     

Selection, validation, standardization, and performance of a designated comparison method for HDL-cholesterol for use in the cholesterol reference method laboratory network.

BACKGROUND: Accurate and precise HDL-cholesterol (HDL-C) measurements are essential for effective application of National Cholesterol Education Program treatment guidelines. The Cholesterol Reference Method Laboratory Network (CRMLN) assists manufacturers of in vitro diagnostic products to establish traceability to the accuracy base. CRMLN sought to implement a designated comparison method (DCM) that overcomes the impracticalities of the expensive and labor-intensive reference method for HDL-C. METHODS: CRMLN evaluated candidate DCMs and selected one that uses 50-kDa dextran sulfate with magnesium ions as the precipitation reagent followed by measurement of cholesterol by the CDC reference method. After validating the method, we transferred it to all CRMLN laboratories and successfully standardized it using CDC frozen serum reference materials. CRMLN laboratories participate in monthly performance evaluations. RESULTS: CRMLN laboratories were able to meet a precision goal, as indicated by SD, of /=1.09 mmol/L (42 mg/dL) 95.6% of the time. CRMLN is working to further improve its performance by implementing a bias criterion of 0.03 mmol/L (1 mg/dL) for all HDL-C concentrations. CONCLUSIONS: CRMLN selected, validated, standardized, and implemented a DCM for HDL-C that is accurate, robust, transferable, and practical. The DCM is being used to assist manufacturers in calibrating their products so that ultimately, clinical laboratories using the products will more accurately measure HDL-C.     

Diet and drug therapy for hypercholesterolemia. Principles and perspectives for the occupational health setting

1. Most individuals with moderately elevated blood cholesterol can lower their cholesterol significantly by following a low fat, low cholesterol diet, which is the first step in the treatment of hypercholesterolemia. 2. The standard low fat, low cholesterol diet recommended by the American Heart Association and the National Cholesterol Education Program restricts total fat intake to less than 30% of calories, with 10% derived from each of the three types of fats (saturated, polyunsaturated, and monounsaturated); and dietary cholesterol to less than 300 mg per day. 3. A client whose LDL cholesterol remains elevated after 6 months on the low fat, low cholesterol diet should be considered a candidate for drug therapy. New guidelines from the National Cholesterol Education Program are now available to assist in selecting the appropriate cholesterol lowering drug for clients with high risk hypercholesterolemia. 4. The current national guidelines for treating hypercholesterolemia offer occupational health nurses new opportunities for teaching risk reduction in the workplace.     

Efficacy and safety of cerivastatin 0.8 mg in patients with hypercholesterolaemia: the pivotal placebo-controlled clinical trial. Cerivastatin Study Group

This pivotal, multicentre, double-blind, parallel-group study evaluated the efficacy and safety of cerivastatin 0.8 mg. Patients with primary hypercholesterolaemia were randomized, after 10 weeks' dietary stabilization on an American Heart Association (AHA) Step I diet, to treatment with cerivastatin 0.8 mg (n = 776), cerivastatin 0.4 mg (n = 195) or placebo (n = 199) once daily for 8 weeks. Cerivastatin 0.8 mg reduced mean low density lipoprotein-cholesterol (LDL-C) by 41.8% compared with cerivastatin 0.4 mg (-35.6%, P < 0.0001) or placebo. In 90% of patients receiving cerivastatin 0.8 mg LDL-C was reduced by 23.9 -58.4% (6th - 95th percentile). Overall attainment of the National Cholesterol Education Program (NCEP) goal was achieved by 84% of patients receiving cerivastatin 0.8 mg and by 59% of those with coronary heart disease (CHD). In the sub-population meeting the NCEP criteria for pharmacological therapy for LDL-C reduction, 74.6% of patients, including the 59% with CHD, reached the goal with cerivastatin 0.8 mg. Cerivastatin 0.8 mg also reduced mean total cholesterol by 29.9%, apolipoprotein B by 33.2% and median triglycerides by 22.9% (all P < 0.0001). Mean high density lipoprotein-cholesterol (HDL-C) and apolipoprotein A1 were elevated 8.7% (P < 0.0001) and 4.5% (P < 0.0001), respectively, by cerivastatin 0.8 mg. Reductions of triglyceride and elevation in HDL-C were dependent upon triglyceride baseline levels; in patients having baseline triglyceride levels 250 - 400 mg/dl, cerivastatin 0.8 mg reduced median triglycerides by 29.5% and elevated HDL-C by 13.2%. Cerivastatin 0.8 mg was well tolerated. The most commonly reported adverse events included headache, pharyngitis and rhinitis (4 - 6%). Symptomatic creatine kinase elevations > 10 times upper limit of normal occurred in 0%, 1% and 0.9% of patients receiving placebo, cerivastatin 0.4 mg or cerivastatin 0.8 mg, respectively. Cerivastatin 0.8 mg is an effective and safe treatment for patients with primary hypercholesterolaemia who need aggressive LDL-C lowering in order to achieve NCEP-recommended levels.     

Prevalence of low HDL-cholesterol in patients with cardiovascular risk factors: The ECHOS (Etude du Cholesterol HDL en Observationnel) French Survey

A low concentration of high-density lipoprotein-cholesterol (HDL-C) is an independent risk factor for cardiovascular heart disease (CHD), but little is known about the distribution of HDL-C in France. This study evaluated the prevalence of low HDL-C among a large French population (5232 patients) with other cardiovascular risk factors. Depending on the guidelines used, the prevalence of low HDL-C varied from 8.7% (cutoff value of 35 mg/dl) to 26.9% (National Cholesterol Education Program metabolic syndrome cutoff values). The prevalence of low HDL-C gradually increased with the number of associated risk factors. We identified three independent risk predictors for low HDL-C: hypertriglyceridaemia (HTG), abdominal obesity and gender. Overall, the frequency of HDL-C assessment was very high (>85%) and it was highest in patients with hypercholesterolaemia or a history of CHD. Risk factors more frequently associated with low HDL-C (i.e. HTG, abdominal obesity and type 2 diabetes) were not associated with a more frequent assessment of HDL-C. Our findings indicate that in France, the prevalence of low HDL-C remains relatively high, particularly for patients with obesity and HTG.     

The metabolic syndrome: pathophysiology, clinical relevance, and use of niacin

OBJECTIVE: To review the pathophysiology and clinical relevance for using niacin to treat the metabolic syndrome. DATA SOURCES: Primary articles were identified through a MEDLINE search (1966-January 2003), and recommendations for treatment were obtained from the National Cholesterol Education Program Adult Treatment Panel (NCEP-ATP) III guidelines. STUDY SELECTION AND DATA EXTRACTION: Published studies showing the effects of the metabolic syndrome, atherogenic dyslipidemia, and niacin were evaluated and reviewed. DATA SYNTHESIS: The metabolic syndrome is a highly prevalent condition that affects 24% of American adults and significantly increases the risk of coronary heart disease (CHD). Most patients with metabolic syndrome have atherogenic dyslipidemia characterized by elevated triglycerides, low high-density-lipoprotein cholesterol (HDL-C), and small, dense low-density-lipoprotein cholesterol (LDL-C) particles. The NCEP-ATP III identifies patients with the metabolic syndrome as candidates for intensified therapy. Lifestyle modifications and drug therapy are recommended. Niacin represents a good option for treating the triad of lipid abnormalities seen in the metabolic syndrome because it raises HDL-C, lowers triglycerides, and increases LDL-C particle size. CONCLUSIONS: Treatment of the metabolic syndrome is recommended by NCEP-ATP III to further reduce CHD risk after the LDL-C target has been met. Prospective clinical studies are needed to define the impact of niacin and other lipid-modifying agents on CHD morbidity and mortality in patients with the metabolic syndrome.     

Update on managing hypercholesterolemia. The new NCEP guidelines.

1. The Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (ATPIII) will significantly increase the number of Americans treated for hypercholesterolemia. 2. The ATPIII focuses on lowering low density lipoprotein cholesterol as a primary initiative and using exercise, diet, and pharmacotherapy as a means for lowering coronary heart disease and risks. 3. The new guidelines list low density lipoprotein cholesterol levels of less than 100 mg/dL as optimal for all clients. 4. The ATPIII places increased attention on high triglyceride levels (> 200 mg/dL) and on early detection and appropriate aggressive treatment for clients at risk for coronary heart disease and events.     

Prospective,noninterventional, uncontrolled,open-chart,pharmacoepidemiologic study of prescribing patterns for lipid-lowering drugs at a tertiary care teaching hospital in North India

BACKGROUND: The guidelines for management of dyslipidemia released by the US National Cholesterol Education Program (NCEP) have been questioned for their relevance in the South Asian Indian populations because these populations are reported to have significantly different lipoprotein parameters and atherogenic risk factors than Western populations. OBJECTIVE: The aim of this study was to determine current prescribing patterns for lipid-lowering drugs (LLDs) adopted by physicians in North India. METHODS: This prospective, noninterventional, uncontrolled, open-chart, pharmacoepidemiologic study was conducted from June 2000 to August 2000 at a tertiary care hospital in North India and included 200 dyslipidemic patients. The pattern of prescribing LLDs was recorded, along with the serum levels of lipid parameters-total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and lipoprotein(a) (Lp[a])-at the time of initiating LLD therapy and compared with the 1993 NCEP-II therapeutic guidelines for dyslipidemia management. RESULTS: The mean (SD) levels of lipid parameters in the study population were as follows: TC, 223.2 (21.5) mg/dL; TG, 258.4 (61.3) mg/dL; LDL-C, 131.6 (26.5) mg/dL; HDL-C, 39.8 (8.9) mg/dL; and Lp(a), 44.8 (26.8) mg/dL. The LLDs prescribed were fibrates (53.5%) and statins (46.5%). Forty percent of patients prescribed LLDs did not meet the NCEP-II criteria for initiation of LLD therapy. CONCLUSIONS: Considerable differences in prescribing patterns of LLDs were observed compared with the then-prevalent NCEP-II guidelines. However, due to the abnormally high serum Lp(a) levels present in the average dyslipidemia profile in South Asian Indian populations, this pattern was in accordance with the specific recommendations made for these populations, as well as with the 2001 NCEP-III guidelines.     

Successful control of dyslipidemia in patients with metabolic syndrome: focus on lifestyle changes

Approaches to controlling dyslipidemia in patients with metabolic syndrome must take into consideration a patient's individual characteristics and underlying lipid disorder. Some patients will require pharmacologic therapy, whereas others can be controlled with lifestyle changes alone. The National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) guidelines recommend that patients with at least 3 of the following clinical variables be designated as having metabolic syndrome: abdominal obesity as reflected in increased waist circumference; a low high-density lipoprotein cholesterol (HDL-C) level; an elevated triglyceride level; elevated blood pressure or treatment with antihypertensive medications; and/or elevated fasting plasma glucose or treatment with antidiabetic medications. Unless patients with metabolic syndrome change their lifestyle, existing cardiovascular and metabolic risk factors will worsen or new risk factors will develop. This helps explain why these patients are at increased risk for developing type 2 diabetes mellitus (DM) and coronary heart disease (CHD). The lifestyle changes recommended by NCEP ATP III for controlling dyslipidemia (i.e., elevated levels of triglycerides and decreased levels of HDL-C) in patients with metabolic syndrome or type 2 DM include (1) reduced intake of saturated fats and dietary cholesterol, (2) intake of dietary options to enhance lowering of low-density lipoprotein cholesterol, (3) weight control, and (4) increased physical activity. If lifestyle changes are not successful for individuals at high risk of developing CHD, or for those who currently have CHD, a CHD risk equivalent, or persistent atherogenic dyslipidemia, then pharmacotherapy may be necessary as defined by NCEP ATP III guidelines.     

Hypercholesterolemia in diabetes and glucose intolerance in the U.S. population

The prevalence of hypercholesterolemia, according to the guidelines of the National Cholesterol Education Program, has been determined in a national survey of diabetes and glucose intolerance. Rates of elevated total cholesterol in people with diabetes in the United States are only slightly greater than in those without diabetes after adjusting for age and sex. Nevertheless, high or borderline high total cholesterol is common in diabetes and is present in 70% of adults with diagnosed diabetes and 77% with undiagnosed diabetes in the U.S. population. Of these individuals, 95% have evidence of coronary heart disease or two or more risk factors for heart disease and should therefore have their low-density lipoprotein (LDL) cholesterol measured. Based on our national data, LDL cholesterol levels warranting dietary treatment for hypercholesterolemia would be expected in 85% of these people. Although elevated LDL cholesterol is uncommon in people with diabetes who have total cholesterol of less than 200 mg/dl, other risk factors for coronary heart disease are very frequent (100% of men, 73% of women), and low total and LDL cholesterol may mask low high-density lipoprotein cholesterol. Therefore, investigation of blood lipid levels and coronary heart disease risk factors should be routine in all patients with diabetes, and treatment strategies should include management of lipid disorders and the multiple other risk factors for coronary heart disease that are highly prevalent in these patients.     

Prevalence of the metabolic syndrome among Omani adults

OBJECTIVE: To estimate the prevalence of the metabolic syndrome by age and sex in the Omani population as defined by the third report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III [ATP III]) of North America. RESEARCH DESIGN AND METHODS: We analyzed data from a cross-sectional survey conducted in 2001 containing a probability random sample of 1,419 Omani adults aged > or =20 years living in the city of Nizwa. The metabolic syndrome, defined by the ATP III, was defined as having three or more of the following abnormalities: waist circumference >102 cm in men and >88 cm in women, serum triglycerides > or =150 mg/dl (1.69 mmol/l), HDL cholesterol <40 mg/dl (1.04 mmol/l) in men and <50 mg/dl (1.29 mmol/l) in women, systolic blood pressure > or =130 mmHg and/or diastolic > or =85 mmHg or on treatment for hypertension, and fasting serum glucose > or =110 mg/dl (6.1 mmol/l) or on treatment for diabetes. RESULTS: The age-adjusted prevalence of the metabolic syndrome was 21.0%. The crude prevalence was slightly lower (17.0%). The age-adjusted prevalence was 19.5% among men and 23.0% among women (P = 0.236). Low HDL cholesterol was the most common component (75.4%) of the metabolic syndrome among the study population followed by abdominal obesity (24.6%). Abdominal obesity was markedly higher in women (44.3%) than in men (4.7%). CONCLUSIONS: The prevalence of the metabolic syndrome in Oman is similar to that in developed countries. Future prevention and control strategies should not overlook the importance of noncommunicable disease risk factors in rapidly developing countries.     

Impact of the third cholesterol report from the adult treatment panel of the national cholesterol education program on the clinical laboratory.

BACKGROUND: The US National Cholesterol Education Program has recently released the third report of the Adult Treatment Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. Incorporating new evidence and more consistent with other international intervention programs, these more complex guidelines will considerably expand indications for treatment. The implications for clinical laboratories are summarized in this report. CONTENT: LDL-cholesterol (LDL-C) remains the major focus for classification and treatment, whereas diabetes, the presence of multiple risk factors, including the metabolic syndrome, and increased triglycerides (TGs), will now require more intensive management. For screening, a fasting lipoprotein profile is recommended, adding LDL-C and TGs to the previous measurements of total cholesterol and HDL-cholesterol (HDL-C). Lowering the cutpoints defining optimal LDL-C [100 mg/dL (2.58 mmol/L)] and normal TGs [150 mg/dL (1.70 mmol/L)] and raising the cutpoint for low HDL-C to 40 mg/dL (1.03 mmol/L) will select more patients for treatment. A new marker, non-HDL-C, becomes a secondary target in treating high TGs. CONCLUSIONS: Laboratories will need to adjust reporting formats and interpretations and can expect more requests for tests to characterize secondary causes of dyslipidemia, e.g., diabetes, and for the so-called "emerging risk factors", e.g., lipoprotein(a), homocysteine, and C-reactive protein.     

A reference method laboratory network for cholesterol: a model for standardization and improvement of clinical laboratory measurements

BACKGROUND: Accurate and precise measurement of blood cholesterol plays a central role in the National Cholesterol Education Program's strategy to reduce the morbidity and mortality attributable to coronary heart disease. Matrix effects hamper the ability of manufacturers to adequately calibrate and validate traceability to the National Reference System for Cholesterol (NRS/CHOL). CDC created the Cholesterol Reference Method Laboratory Network (CRMLN) to improve cholesterol measurement by assisting manufacturers of in vitro diagnostic products with validation of the traceability of their assays to the NRS/CHOL. METHODS: CRMLN laboratories established the CDC cholesterol reference method (modification of the Abell-Levy-Brodie-Kendall chemical method) and are standardized using CDC frozen serum reference materials. CRMLN laboratories use common quality-control materials and participate in monthly external performance evaluations conducted by CDC. The CRMLN performance criteria require member laboratories to agree with CDC within +/-1.0% and maintain a CV < or =2.0%. RESULTS: From 1995 to 200 the CRMLN laboratories met the accuracy criterion 97% of the time and the precision criterion 99% of the time. During this time period, the CRMLN maintained an average bias to CDC of 0.01% and an average collective CV of 0.33%. CONCLUSIONS: CDC established the CRMLN as the first international reference method laboratory network. The CRMLN assists manufacturers in the validation of the calibration of their diagnostic products so that clinical laboratories can measure blood cholesterol more reliably. The CRMLN can serve as a model for other clinical analytes where traceability to a hierarchy of methods is needed and matrix effects of the field methods with processed calibrators or reference materials are present.     

Cholesterol guidelines update: more aggressive therapy for higher-risk patients

The 2004 update to the National Cholesterol Education Program guidelines goes farther than the 2001 version in suggesting an optional low-density lipoprotein cholesterol (LDL-C) goal of less than 70 mg/dL for patients at "very high risk." It recommends starting both diet and drug therapy in all patients at high or very high risk whose LDL-C level is above the goal level, with the goal of reducing LDL-C by 30% to 40%. These more aggressive guidelines are based on results of five clinical studies published since 2001.