The benefits of reducing cholesterol levels: the need to distinguish primary from secondary prevention. 1. A meta-analysis of cholesterol-lowering trials.

OBJECTIVE: To use meta-analysis to estimate the benefits of drug treatment to lower cholesterol levels in the primary and secondary prevention of coronary heart disease (CHD) events. DATA SOURCES: MEDLINE search from 1967 to 1990; bibliographies of review articles. STUDY SELECTION: Nine trials met the entry criteria: they were monofactorial, randomised and controlled. DATA EXTRACTION: Two independent, unblinded observers. DATA SYNTHESIS: The odds ratio (and 95% Cl) for death from CHD was 0.85 (0.64, 1.14) in primary prevention and 0.84 (0.75, 0.95) in secondary prevention studies when calculated by the method of Peto. The event rate in the secondary prevention studies was higher than that in the primary prevention studies, and the absolute risk reduction achieved by therapy in the former (3.2%) was much higher than that in the latter (0.1%). The number of subjects needing to be treated to prevent one death from CHD was 38 in secondary prevention and 675 in primary prevention. Results with the method of DerSimonian and Laird were similar. CONCLUSIONS: The benefits of cholesterol lowering to prevent death from CHD are substantially greater in the secondary prevention setting than in primary prevention.     

Cost-effectiveness of HMG-CoA reductase inhibition for primary and secondary prevention of coronary heart disease

To determine the cost-effectiveness of HMG-CoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase inhibitors (such as lovastatin) for the primary and secondary prevention of coronary heart disease, we used the Coronary Heart Disease Policy Model, a computer-stimulated model that estimates the risk factor-specific annual incidence of coronary heart disease and the risk of recurrent coronary events in persons with prevalent coronary heart disease. When used for secondary prevention, 20 mg/d of lovastatin was estimated to save lives and save costs in younger men with cholesterol levels above 250 mg/dL (6.47 mmol/L) and to have a favorable cost-effectiveness ratio regardless of the cholesterol level except in young women with cholesterol levels below 250 mg/dL (6.47 mmol/L). Doses of 40 mg/d of lovastatin had favorable incremental cost-effectiveness ratios in men with cholesterol levels above 250 mg/dL (6.47 mmol/L). By comparison, primary prevention had favorable cost-effectiveness ratios only in selected subgroups based on cholesterol levels and other established risk factors. We conclude that current national recommendations regarding medication for secondary prevention are not as aggressive as our projections would suggest, while recommendations regarding the use of medications for primary prevention should consider the cost of medication as well as the risk factor profile of the individual patient.     

Relationship of baseline serum cholesterol levels in 3 large cohorts of younger men to long-term coronary, cardiovascular, and all-cause mortality and to longevity

CONTEXT: Based on observational and interventional data for middle-aged cohorts (aged 40-64 years), serum cholesterol level is known to be an established major risk factor for coronary heart disease (CHD). However, findings for younger people are limited, and the value of detecting and treating hypercholesterolemia in younger adults is debated. OBJECTIVE: To evaluate the long-term impact of unfavorable serum cholesterol levels on risk of death from CHD, cardiovascular disease (CVD), and all causes. DESIGN, SETTING, AND PARTICIPANTS: Three prospective studies, from which were selected 3 cohorts of younger men with baseline serum cholesterol level measurements and no history of diabetes mellitus or myocardial infarction. A total of 11,017 men aged 18 through 39 years screened in 1967-1973 for the Chicago Heart Association Detection Project in Industry (CHA); 1266 men aged 25 through 39 years examined in 1959-1963 in the Peoples Gas Company Study (PG); and 69,205 men aged 35 through 39 years screened in 1973-1975 for the Multiple Risk Factor Intervention Trial (MRFIT). MAIN OUTCOME MEASURES: Cause-specific mortality during 25 (CHA), 34 (PG), and 16 (MRFIT) years of follow-up; mortality risks; and estimated life expectancy in relation to baseline serum cholesterol levels. RESULTS: Death due to CHD accounted for 26%, 34%, and 28% of all deaths in the CHA, PG, and MRFIT cohorts, respectively; and CVD death for 34%, 42%, and 39% of deaths in the same cohorts, respectively. Men in all 3 cohorts with unfavorable serum cholesterol levels (200-239 mg/dL [5.17-6.18 mmol/L] and >/=240 mg/dL [>/=6.21 mmol/L]) had strong gradients of relative mortality risk. For men with serum cholesterol levels of 240 mg/dL or greater (>/=6.21 mmol/L) vs favorable levels (<200 mg/dL [<5.17 mmol/L]), CHD mortality risk was 2.15 to 3.63 times greater; CVD disease mortality risk was 2.10 to 2.87 times greater; and all-cause mortality was 1.31 to 1.49 times greater. Hypercholesterolemic men had age-adjusted absolute risk of CHD death of 59 per 1000 men in 25 years (CHA cohort), 90 per 1000 men in 34 years (PG cohort), and 15 per 1000 men in 16 years (MRFIT cohort). Absolute excess risk was 43.6 per 1000 men (CHA), 81.4 per 1000 men (PG), and 12.1 per 1000 men (MRFIT). Men with favorable baseline serum cholesterol levels had an estimated greater life expectancy of 3.8 to 8.7 years. CONCLUSIONS: These results demonstrate a continuous, graded relationship of serum cholesterol level to long-term risk of CHD, CVD, and all-cause mortality, substantial absolute risk and absolute excess risk of CHD and CVD death for younger men with elevated serum cholesterol levels, and longer estimated life expectancy for younger men with favorable serum cholesterol levels. JAMA. 2000;284:311-318     

Relation of gemfibrozil treatment and lipid levels with major coronary events: VA-HIT: a randomized controlled trial

CONTEXT: A low plasma level of high-density lipoprotein cholesterol (HDL-C) is a major risk factor for coronary heart disease (CHD). A secondary prevention study, the Veterans Affairs High-Density Lipoprotein Intervention Trial (VA-HIT), demonstrated that CHD events were significantly reduced during a median follow-up of 5.1 years by treating patients with the fibric acid derivative gemfibrozil when the predominant lipid abnormality was low HDL-C. OBJECTIVE: To determine if the reduction in major CHD events with gemfibrozil in VA-HIT could be attributed to changes in major plasma lipid levels. DESIGN: Multicenter, randomized, double-blind, placebo-controlled trial conducted from September 1991 to August 1998. SETTING: The Department of Veterans Affairs Cooperative Studies Program, in which 20 VA medical centers were participating sites. PARTICIPANTS: A total of 2531 men with a history of CHD who had low HDL-C levels (mean, 32 mg/dL [0.83 mmol/L] ) and low low-density lipoprotein cholesterol (LDL-C) levels (mean, 111 mg/dL [2.88 mmol/L]). INTERVENTION: Participants were randomly assigned to receive gemfibrozil, 1200 mg/d (n = 1264), or matching placebo (n = 1267). MAIN OUTCOME MEASURE: Relation of lipid levels at baseline and averaged during the first 18 months of gemfibrozil treatment with the combined incidence of nonfatal myocardial infarction and CHD death. RESULTS: Concentrations of HDL-C were inversely related to CHD events. Multivariable Cox proportional hazards analysis showed that CHD events were reduced by 11% with gemfibrozil for every 5-mg/dL (0.13-mmol/L) increase in HDL-C (P =.02). Events were reduced even further with gemfibrozil beyond that explained by increases in HDL-C values, particularly in the second through fourth quintiles of HDL-C values during treatment. During gemfibrozil treatment, only the increase in HDL-C significantly predicted a lower risk of CHD events; by multivariable analysis, neither triglyceride nor LDL-C levels at baseline or during the trial predicted CHD events. CONCLUSIONS: Concentrations of HDL-C achieved with gemfibrozil treatment predicted a significant reduction in CHD events in patients with low HDL-C levels. However, the change in HDL-C levels only partially explained the beneficial effect of gemfibrozil.     

The benefits of treating hyperlipidemia to prevent coronary heart disease. Estimating changes in life expectancy and morbidity.

OBJECTIVE--To evaluate the lifetime benefits of reducing total serum cholesterol levels to prevent coronary heart disease (CHD). DESIGN--We developed a CHD primary prevention computer model to estimate the benefits associated with lifelong risk factor modification. We validated the model by comparing the computer estimates with the observed results of three primary CHD prevention trials. PATIENTS--Men and women age 35 to 65 years who are free of CHD, with total serum cholesterol levels ranging from 5.2 to 7.8 mmol/L (200 to 300 mg/dL), with or without additional CHD risk factors. INTERVENTIONS--Serum cholesterol reduction through dietary modification or diet and medications. MAIN OUTCOME MEASURES--Changes in life expectancy and the delay of symptomatic CHD. RESULTS--The computer forecasts for CHD end points closely matched the observed results of the Lipid Research Clinics Trial, the Helsinki Heart Study, and MRFIT. We then applied the computer model to low-risk and high-risk men and women with total serum cholesterol levels between 5.2 and 7.8 mmol/L (200 and 300 mg/dL) and estimated that, after reducing serum cholesterol levels 5% to 33%, the average life expectancy would increase by 0.03 to 3.16 years. We also forecast that the average onset of symptomatic CHD would be delayed among these patient groups by 0.06 to 4.98 years. CONCLUSION--We conclude that this computer model accurately estimates the results of clinical trials and can be used to forecast the changes in life expectancy and morbidity (the development of CHD) associated with specific CHD risk reduction interventions. The wide variation surrounding these estimates underscores the need to better define which groups of individuals will gain the most from cholesterol reduction.     

Is relationship between serum cholesterol and risk of premature death from coronary heart disease continuous and graded? Findings in 356,222 primary screenees of the Multiple Risk Factor Intervention Trial (MRFIT)

The 356,222 men aged 35 to 57 years, who were free of a history of hospitalization for myocardial infarction, screened by the Multiple Risk Factor Intervention Trial (MRFIT) in its recruitment effort, constitute the largest cohort with standardized serum cholesterol measurements and long-term mortality follow-up. For each five-year age group, the relationship between serum cholesterol and coronary heart disease (CHD) death rate was continuous, graded, and strong. For the entire group aged 35 to 57 years at entry, the age-adjusted risks of CHD death in cholesterol quintiles 2 through 5 (182 to 202, 203 to 220, 221 to 244, and greater than or equal to 245 mg/dL [4.71 to 5.22, 5.25 to 5.69, 5.72 to 6.31, and greater than or equal to 6.34 mmol/L]) relative to the lowest quintile were 1.29, 1.73, 2.21, and 3.42. Of all CHD deaths, 46% were estimated to be excess deaths attributable to serum cholesterol levels 180 mg/dL or greater (greater than or equal to 4.65 mmol/L), with almost half the excess deaths in serum cholesterol quintiles 2 through 4. The pattern of a continuous, graded, strong relationship between serum cholesterol and six-year age-adjusted CHD death rate prevailed for nonhypertensive nonsmokers, nonhypertensive smokers, hypertensive nonsmokers, and hypertensive smokers. These data of high precision show that the relationship between serum cholesterol and CHD is not a threshold one, with increased risk confined to the two highest quintiles, but rather is a continuously graded one that powerfully affects risk for the great majority of middle-aged American men.     

高密度脂蛋白对老年人冠心病的保护作用

目的　分析高密度脂蛋白胆固醇 (HDL C)水平与急性心肌梗死 (AMI)及冠心病 (CHD)死亡的关系 ,及高HDL水平对CHD的保护作用。方法　长期随访 12 11例老年离休干部 ,平均年龄入组时为 70± 9岁 ,终点 80± 9岁。随访时间为 1986～ 2 0 0 0年 ,平均随访 11 2年。按HDL C水平分为低 (<1 0 3mmol/L)中 (正常 ,1 0 3～ 1 5 6mmol/L)及高 (>1 5 6mmol/L) 3组 ,比较各组中AMI事件及CHD死亡率的差异。结果　随访期间累计发生CHD事件 (大都为AMI) 2 14例 ,其中死亡 89例 ,其他原因死亡 30 8例。HDL C从低水平组升至正常水平组时 ,AMI减少 4 0 % ,CHD死亡减少 5 3% ;从正常水平组升至高水平组时 ,AMI减少 5 6 % ,CHD死亡减少 5 0 %。单独将血脂正常 (总胆固醇 <5 17mmol/L、甘油三酯 <1 6 9mmol/L)的病例 (4 11例 )做统计分析 ,虽然低HDL C的致病作用仍很明显 ,但HDL C在正常与高水平时 ,发病与死亡数减少极明显。结论　对于老年人的AMI发病和CHD死亡 ,低HDL C仍是明显的独立危险因素 ,高HDL C水平对冠状动脉病的保护作用极为显著。在血脂不高的情况下 ,HDL对冠状动脉的保护作用更强。     

Apparent protective effect of high density lipoprotein against coronary heart disease in the elderly

Background This study was designed to evaluate the relationship between high-density lipoprotein cholesterol (HDL-C) level and acute myocardial infarction (AMI) and coronary heart disease (CHD) death and to explore the protective effect of HDL against CHD in the elderly Chinese.Methods Started from 1986, 1211 retirees (92% males) were enrolled consecutively and studied prospectively. The average starting age was 70±9 years, and that at the end of the study was 80±9 years. During the follow-up study, all the participants received yearly physical examination and blood chemistry survey from 1986-2000. The average duration of the follow up study was 11.2 years. The end point of this study was either attacks of AMI or death due to CHD and other causes. CHD risk factors were screened by logistic regression analysis. According to their HDL-C levels, cases were divided into low (&lt;1.03 mmol/L), medium (or normal, 1.03-1.56 mmol/L) and high (&gt;1.56 mmol/L) level groups, the differences in incidence of AMI and CHD death in each group were analyzed.Results The cumulative attacks of acute coronary syndrome (mostly AMI) were 214 cases, including 89 cases of coronary death and 308 death caused by other diseases during the follow up study. AMI occurrence and CHD death in normal HDL-C group were lower than those in the low HDL-C group by 40% and 53%; and those in the high HDL-C group were lower than in the normal group by 56% and 50%, respectively. Statistical analysis on normal lipid cases （411 cases, total cholesterol&lt;5.17mmol/L, triglyceride&lt;1.69 mmol/L） revealed that the cases at low HDL-C level had similar rates of AMI events and CHD mortality as those of the entire group (including hyperlipidemia); however, AMI attacks and CHD deaths decreased significantly at the normal and high HDL-C levels. The results demonstrated that the protective effect of HDL against coronary artery disease is more prominent in people with low lipid level.Conclusion Low HDL is an important independent risk factor for AMI attacks and CHD death in the elderly; high HDL has significant protective effect against coronary artery disease.     

Impact of treating hyperlipidemia or hypertension to reduce the risk of death from coronary artery disease

OBJECTIVE: To compare the prevalence of modifiable risk factors for cardiovascular disease among hypertensive and nonhypertensive adults and to estimate the effect of treating hyperlipidemia or hypertension to reduce the risk of death from coronary artery disease. METHODS: The authors evaluated a sample of 7814 subjects aged 35-74 years free of clinical cardiovascular disease from the Canadian Heart Health Surveys to estimate the prevalence of cardiovascular risk factors. They identified hyperlipidemic subjects (ratio of total cholesterol to high-density lipoprotein cholesterol [total-C/HDL-C] 6.0 [corrected] or more for men and 5.0 [corrected] or more for women) and hypertensive subjects (systolic or diastolic blood pressure 160/90 mm Hg or greater, or receiving pharmacologic or nonpharmacologic treatment). A life expectancy model was used to estimate the rate of death from coronary artery disease following specific treatments. RESULTS: An elevated total-C/HDL-C ratio was significantly more common among hypertensive than nonhypertensive men aged 35-64 (rate ratio [RR] 1.56 for age 35-54, 1.28 for age 55-64) and among hypertensive than nonhypertensive women of all ages (RR 2.73 for age 35-54, 1.58 for age 55-64, 1.31 for age 65-74). Obesity and a sedentary lifestyle were also more common among hypertensive than among nonhypertensive subjects. According to the model, more deaths from coronary artery disease could be prevented among subjects with treated but uncontrolled hypertension by modifying lipids rather than by further reducing blood pressure for men aged 35-54 (reduction of 50 v. 29 deaths per 100,000) and 55-64 (reduction of 171 v. 104 deaths per 100,000) and for women aged 35-54 (reduction of 44 v. 39 deaths per 100,000). Starting antihypertensive therapy in subjects aged 35-74 with untreated hypertension would achieve a greater net reduction in deaths from coronary artery disease than would lipid lowering. Nonetheless, the benefits of lipid therapy were substantial: lipid intervention among hypertensive subjects aged 35-74 represented 36% of the total benefits of treating hyperlipidemia in the total hyperlipidemic population. INTERPRETATION: The clustering of hyperlipidemia and the potential benefits of treatment among hypertensive adults demonstrate the need for screening and treating other cardiovascular risk factors beyond simply controlling blood pressure.     

An evidence-based assessment of the NCEP Adult Treatment Panel II guidelines. National Cholesterol Education Program

CONTEXT: The Second Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel II) was issued without the benefit of multiple recently published large clinical trials. OBJECTIVE: To analyze the panel's guidelines for treatment of high cholesterol levels in the context of currently available clinical trial results. DATA SOURCES: MEDLINE was searched for all English-language clinical trial data from 1993 through February 1999 relating to the effects of cholesterol treatment on cardiovascular clinical outcomes. STUDY SELECTION: Studies that were selected for detailed review assessed the effects of cholesterol lowering on either coronary events, coronary mortality, stroke, and/or total mortality, preferably by randomized, double-blind, placebo-controlled design. Selection was by consensus of a general internist, a lipid clinic director, and a researcher in atherosclerotic plaque biology. A core of 37 of the 317 initially screened studies were selected and used as the primary means by which to assess the guidelines. DATA EXTRACTION: By consensus of the group, only prespecified end points of trials were included, unless post hoc analysis addressed issues not studied elsewhere. DATA SYNTHESIS: Recent clinical trial data mostly support the Adult Treatment Panel II guidelines for cholesterol management. While existing trials have validated the target low-density lipoprotein cholesterol (LDL-C) goals in the report, studies are lacking that address mortality benefit from reduction below these levels. Few lipid-lowering trials have treated patients with low high-density lipoprotein cholesterol and/or elevated triglyceride levels with LDL-C levels at or below treatment goals. CONCLUSIONS: Lipid-lowering therapy generally should be more aggressively applied to patients with diabetes and/or at the time of coronary heart disease (CHD) diagnosis. The evidence for statin use in secondary CHD prevention in postmenopausal women outweighs current evidence for use of estrogen replacement in this setting. Further studies are needed to address the effects of lipid modification in primary prevention of CHD in populations other than middle-aged men and to study markers of lipid metabolism other than LDL-C.     

A long-term follow-up study of serum lipid levels and coronary heart disease in the elderly

Background It is still controversial whether or not the correlation between lipid abnormality and coronary heart disease (CHD) becomes weaker in the elderly, and whether patients above 80 years old still benefit from lipid management for the secondary prevention of CHD. The purpose of this study is to assess the correlation between hyperlipidemia and the risk of CHD events in the elderly, and to determine if it is appropriate to use lipid-lowering drugs in those aged above 80, as prescribed by the recommended guidelines for lipid management.Methods One thousand two hundred and eleven retirees, mainly males (92%), aged 70±9 years, were enrolled in this study. Lifestyle habits and medical history were recorded via questionnaires. During the period 1986 -2000, all subjects participated in an annual physical examination with a blood chemistry survey. The mean follow-up period was 11.2 years. Subjects with incidental illnesses, especially cardiovascular diseases, were diagnosed or treated promptly. Serum li     

Guidelines for the detection of high-risk lipoprotein profiles and the treatment of dyslipoproteinemias. Canadian Lipoprotein Conference Ad Hoc Committee on Guidelines for Dyslipoproteinemias.

Elevated plasma levels of cholesterol and triglycerides, low levels of high-density lipoproteins, hypertension, diabetes mellitus, smoking and abdominal obesity are risk factors for coronary heart disease (CHD) and stroke. Because of the preventable threat to life, well-being and productivity from perturbations of plasma lipoproteins (which affect about 60% of adults), we recommend a population-based strategy with public education on diet, exercise and the hazards of smoking and legislation for better food labelling. This should be combined with the medical guidelines we describe to detect and treat those at highest risk for CHD (including about 15% of adults), who merit priority for the medical, dietetic and laboratory services required. Among people aged 40 years or more this includes those with plasma total cholesterol levels greater than 7 mmol/L, fasting triglyceride levels greater than 3 mmol/L or cholesterol level greater than 6 mmol/L when associated with CHD or other risk factors for CHD. For younger people the criteria for highest risk include cholesterol levels greater than 6.5 mmol/L for those aged 30 to 39 years, greater than 6 mmol/L for those aged 20 to 29 and greater than 5 mmol/L for those under age 20.     

Treatment target re-classification of subjects comparing estimation of low-density lipoprotein cholesterol by the Friedewald equation and direct measurement of LDL-cholesterol

Aims: To compare low-density lipoprotein cholesterol (LDL-C) values calculated by the Friedewald equation with direct LDL-C in patient samples and assess the possible impact on re-classification of LDL-C target values for primary prevention or high cardiovascular disease (CVD) risk (<2.5?mmol/L) and secondary prevention or very high CVD risk (<1.8?mmol/L). LDL-C is an important CVD risk factor. Over the last decade, there has been a change in laboratory methodology from indirectly calculated LDL-C with the Friedewald equation to direct LDL-C measurements (dLDL-C).

Methods: Reported results for plasma triglycerides, total cholesterol, high-density lipoprotein-cholesterol, and dLDL-C from 34,981 samples analyzed in year 2014 were extracted from the laboratory information system, Uppsala University Hospital, Uppsala, Sweden.

Results: dLDL-C was approximately 10% lower than the corresponding LDL-C results calculated by the Friedewald equation in both men and women. In subjects with triglyceride concentrations above 4?mmol/L (n?=?1250) the same discordant pattern was seen as for the entire study population. Altogether 5469 out of 18,051 men (30.3%) and 4604 out of 16,928 women (27.2%) were down-classified at least one CVD risk category. A very small number of subject was up-classified, in total 37 out of 18,051 men (0.2%) and 28 out of 16,928 women (0.2%).

Conclusions: The two LDL-C methods had a high concordance, but the direct LDL-C measurement consistently gave approx. 10% lower values, and this caused one-third of subjects to be re-classified as having a lower cardiovascular disease risk in relation to recommended LDL-C target values and decision limits.     

Statins: Can we advocate them for primary prevention of heart disease?

The discovery of cholesterol-lowering agents, namely HMG-CoA reductase inhibitors or statins, ushered in a series of large cholesterol reduction trials. The first of these studies was the Scandinavian Simvastatin Survival Study (4S) in which hypercholesterolemic men with CHD who were treated with simvastatin had a reduction in major coronary events of 44% and a reduction in total mortality of 30%. Many more secondary prevention trials followed to establish unequivocally the benefit of cholesterol reduction. Strategies that aim to improve primary prevention are important for managing the overall burden of disease. Recently therefore, the role of statin in primary prevention is being debated. The JUPITER trial and more recently the Cholesterol Treatment Trialists collaborators, proved that incidences of first major cardiovascular events in apparently healthy individuals were reduced by statins. Statins have also been discussed to be having certain pleiotropic effects on other diseases like diabetes, cancer and osteoporosis. However, issues of cost effectiveness and adverse effects like myositis, and transaminitis still loom large. The medical community needs to debate and evolve a possible consensus on the path breaking subject.     

Primary and secondary prevention trials in coronary heart disease

Trials in primary and secondary prevention of coronary heart disease (CHD) are reviewed. The results of completed primary prevention trials suggest that dietary changes in middle-aged men may lower the incidence of CHD. Multifactorial trials may achieve an even greater reduction in CHD. Secondary prevention trials indicate that stopping smoking and the use of beta-blocking agents are effective in reducing recurrence rates.     

Death during jogging or running. A study of 18 cases.

We investigated the circumstances of death and the medical and activity histories of 18 individuals who died during or immediately after jogging. Thirteen men died of coronary heart disease (CHD) and four men and one woman died of other causes. Six CHD subjects had medical histories relevant to the cardiovascular system, but only one had diagnosed CHD. Six CHD subjects experienced prodromal symptoms but continued vigorous exercise programs. Two subjects had exercised less than a month, but most had trained regularly for years. The CHD risk factors for the CHD cases did not differ significantly from those for other age-matched, physically active men. Superior physical fitness does not guarantee protection against exercise deaths. Physicians and exercising adults should be aware of this fact and give appropriate attention to possible prodromal symptoms.     

Lipids and lipoproteins in patients undergoing coronary-artery surgery

Fasting blood samples were obtained from 290 patients who were undergoing elective coronary-artery graft procedures, and cholesterol, triglyceride and high-density lipoprotein cholesterol levels were measured. The 1983 National Heart Foundation of Australia's Risk Factor Prevalence Study was used as a source of age- and sex-matched "control" data. Of these patients, 80% had cholesterol levels of greater than 5.5 mmol/L; in 55% of patients, the level exceeded 6.5 mmol/L. Only 4% of patients who received a graft showed hypertriglyceridaemia alone (triglyceride level, greater than 2 mmol/L). Combined hyperlipidaemia (cholesterol level, greater than 5.5 mmol/L and triglyceride level, greater than 2.0 mmol/L) was present in 52% of subjects. Low-density lipoprotein cholesterol levels exceeded 3.5 mmol/L in 69% of men and in 71% of women. In terms of five 10-year age intervals, mean plasma triglyceride and cholesterol levels were elevated significantly in patients who had undergone a coronary-artery grafting procedure compared with those of subjects in the National Heart Foundation study. The mean high-density lipoprotein cholesterol levels were markedly-lower compared with those of the subjects in the National Heart Foundation study. Of those patients whose plasma cholesterol levels were less than 5.5 mmol/L, 97% of patients had high-density lipoprotein cholesterol levels that were less than the mean level for subjects in the National Heart Foundation study. Thus, a very-high proportion of patients who underwent coronary-artery bypass surgery had lipid abnormalities which required intervention postoperatively.     

Plasma lipids and lipoproteins and the prevalence of risk for coronary heart disease in Canadian adults. Canadian Heart Health Surveys Research Group.

OBJECTIVE: To report population reference values for blood lipids, to determine the prevalence of lipid risk factors and to assess their association with other risk factors. DESIGN: Population-based cross-sectional surveys. Survey participants were interviewed at home and provided a blood sample at a clinic. All blood lipid analyses were done in the Lipid Research Laboratory, University of Toronto. The laboratory is standardized in the National Heart, Lung Blood Institute-Centres for Disease Control Standardization Program. SETTING: Nine Canadian provinces, from 1986 to 1990. PARTICIPANTS: A probability sample of 26,293 men and women aged 18 to 74 was selected from the health insurance registers for each province. Blood samples were obtained from 16,924 participants who had fasted 8 hours or more. OUTCOME MEASURES: Concentration of total plasma cholesterol, triglycerides and high density lipoprotein (HDL) and low density lipoprotein (LDL) cholesterol in blood samples from fasting participants. MAIN RESULTS: Of the study population, 46% had total plasma cholesterol levels above 5.2 mmol/L, 15% had LDL-cholesterol levels above 4.1 mmol/L, 15% had triglyceride levels above 2.3 mmol/L and 8% had HDL-cholesterol levels below 0.9 mmol/L. Total plasma cholesterol, LDL-cholesterol and triglyceride levels rose with age in men to a maximum in the 45-54 age group; in women there was little change with age up to ages 45 to 54, at which time the level of each of these lipids increased appreciably. The age-standardized prevalence of obesity was positively associated with elevation of total plasma cholesterol. CONCLUSION: The results suggest the need for a multifactorial approach in health promotion efforts to lower blood cholesterol levels and reduce other risk factors in the population. A considerable number of adults were found to be at risk at all ages in both sexes. In the short term, men aged 34 and older and women aged 45 and older might benefit most from prevention programs.     

Long-term antiplatelet therapy for the prevention of vascular disease

OBJECTIVE: To estimate the effects of prolonged antiplatelet therapy on the primary and secondary incidence of vascular disease. DATA SOURCES: Twenty-five randomised trials in 29,000 patients with a history of vascular disease (the Antiplatelet Trialists' Collaboration) and two randomised trials in 27,000 individuals without a history of vascular disease (the British doctors' and American physicians' studies). STUDY SELECTION: The Antiplatelet Trialists' Collaboration obtained data from all randomised trials of secondary prevention completed before January 1988. The British doctors' and American physicians' studies are the only two completed randomised trials of primary prevention. DATA EXTRACTION: Data from the secondary prevention trials were provided by the Antiplatelet Trialists' Collaboration. Data from the primary prevention trials were extracted from the final published reports of these studies. DATA SYNTHESIS: In the secondary prevention trials, antiplatelet therapy reduced the rate of vascular disease by about 15% and the incidence of non-fatal myocardial infarction and stroke by about 30%. In the American physicians' study, but not the British doctors' study, the incidence of non-fatal myocardial infarction was also reduced. In neither primary prevention trial was there evidence of reduced rates of non-fatal stroke or vascular death; overall, fatal or disabling strokes were slightly more frequent among those assigned aspirin. CONCLUSIONS: For patients with a history of vascular disease, the benefits of antiplatelet therapy appear to outweigh any risks. Among 100 such patients, antiplatelet therapy for two years would prevent one death and two major non-fatal events. The balance of benefits and risks for individuals without a history of vascular disease is less clear because there is no firm evidence of a net reduction in either vascular death or disabling non-fatal vascular events among those treated with aspirin.