The cholesterol papers

Hormone replacement therapy and cardiovascular risk: the cardiovascular physicians' viewpoint

Sufficient evidence has accumulated showing that hormone replacement therapy (HRT) does protect against cardiovascular disease in women, although data regarding the true magnitude of that protection remains incomplete. There is no evidence that HRT increases the risk of hypertension or thromboembolism, and beneficial effects have been found for plasma lipids, clotting factors and cardiovascular haemodynamics. However, the evidence is not convincing of any beneficial effect of HRT in preventing strokes, and concerns about the risk of cancer with HRT remain. Despite this, considerable uncertainty continues to exist amongst clinicians as to the balance of beneficial and harmful effects from administering HRT. Overall, HRT seems to do no harm and may be protective. A much greater awareness of the long-term consequences of the menopause and the potential benefits of HRT should be encouraged so that women (and their doctors) can make informed decisions about their requirements.

Cholesterol reduction yields clinical benefit. A new look at old data

BACKGROUND

There has been a continuing debate about the overall benefit of cholesterol lowering. We performed a novel meta-analysis of all randomized trials of more than 2 years' duration (n = 35 trials) to describe how coronary-heart-disease (CHD), non-CHD, and total mortality are related to cholesterol lowering and to type of intervention.

METHODS AND RESULTS

The analytic approach was designed to separate the effects of cholesterol lowering itself from the other effects of the different types of intervention used. For every 10 percentage points of cholesterol lowering, CHD mortality was reduced by 13% (P < .002) and total mortality by 10% (P < .03). Cholesterol lowering had no effect on non-CHD mortality. Certain types of intervention had specific effects independent of cholesterol lowering. Fibrates (clofibrates, 7 trials; gemfibrozil, 2 trials) increased non-CHD mortality by about 30% (P < .01) and total mortality by about 17% (P < .02). Hormones (estrogen, 2 trials; dextrothyroxin, 2 trials) increased CHD mortality in men by about 27% (P < .04), non-CHD mortality by about 55% (P < .03), and total mortality by about 33% (P < .01). No specific effects independent of cholesterol lowering were found due to diet (n = 11) or other interventions (resins, 5; niacin, 3; statins, 2; partial ileal bypass, 1).

CONCLUSIONS

The results suggest that cholesterol lowering itself is beneficial but that specific adverse effects of fibrates and hormones increase the risk of CHD (hormones only), non-CHD, and total mortality.

Goals of antihypertensive therapy

Antihypertensive therapy has been used for almost 40 years to reduce blood pressure and to prevent morbidity and mortality related to the hypertensive state. Cardiovascular events are related to the initial elevation of blood pressure; the benefits of treating malignant, severe or moderate hypertension are well established. Although large scale clinical trials have demonstrated a decrease in morbid events when mildly elevated blood pressures is treated, the benefits are neither universal or dramatic and treatment is certainly less cost effective than no treatment. Recently it has been emphasised that the absolute risk of cardiovascular events is determined only in part by blood pressure, and that it is also influenced by age, gender, race and the presence of other cardiovascular risk factors. For example, in older individuals where the absolute risk of vascular complications is greater than in younger individuals for any given level of blood pressure, the benefits of therapy will be greater. It has been suggested that in younger individuals with mild hypertension and a low absolute risk of developing cardiovascular morbid events it may be more appropriate to monitor the effects of drug therapy on measures of cardiac and vascular damage that are associated with the hypertensive state. Drug therapy has been shown to be extremely effective in reducing the incidence of stroke, congestive cardiac failure and renal failure associated with elevated blood pressure. Meta-analysis of randomised large scale clinical trials indicates that drug therapy may not reduce coronary events to the extent expected in patients with hypertension. One plausible explanation is that the trials have been of insufficient duration to detect the benefit of blood pressure lowering on coronary heart disease. It has also been suggested that certain adverse metabolic effects associated with the use of thiazide diuretics and beta-blockers employed in these trials may have partially offset the benefits of blood pressure reduction. However, the clinical significance of these drug-induced metabolic disturbances remains unclear. Experimental data suggesting differences in the ability of antihypertensive drugs to inhibit atherosclerosis in animal models are also of interest, but again the relation of the findings to the clinical situation is unknown. Thiazide diuretics, beta-blockers, calcium antagonists, angiotensin-converting enzyme (ACE) inhibitors and alpha-blockers can produce regression of left ventricular hypertrophy (LVH). While LVH is clearly a strong and independent predictor for coronary disease, it remains to be shown that a lower risk for coronary morbid events exists in patients whose LVH has undergone regression over and above that attributable to blood pressure reduction.(ABSTRACT TRUNCATED AT 400 WORDS)

The risk epidemic in medical journals

Searches in MEDLINE databases show a rapid increase in the number of articles with the term 'risk(s)' in the title and/or abstract in the period from 1967 to 1991. This trend is found in medical journals giving a general coverage of medicine and journals covering obstetrics and gynaecology in U.S.A., Britain and Scandinavia. The most rapid increase is, however, found in epidemiological journals. Comparisons of the developments in the occurrence of such terms as risk, hazard, danger and uncertainty show that the increasing frequency of the term risk in the medical literature can not be explained as a change in terminology alone. It is hypothesized that the ongoing trend, which resembles an epidemic, is a result of developments in science and technology, that has changed our beliefs about the locus of control from factors outside human control to factors inside our control. The origins of the epidemic may be traced to the development of such disciplines as probability statistics, increased focus on risk management and health promotion, with recent developments in computer technology as the factor responsible for the escalation seen in the past decade. With the cultural selection of risks in mind, the social construction of risk is discussed. Potentially harmful effects of such an epidemic are discussed, exemplified through controversies over current epidemiological risk construction and strategies for coronary risk reduction. It is finally argued that the risk epidemic reflects the social constructions of a particular culture at a particular time in history.

General practitioners' tacit and stated policies in the prescription of lipid lowering agents

BACKGROUND

Research into general practitioners' prescribing behaviour with regard to lipid lowering agents has relied on survey methods which presume that doctors have insight into their prescribing behaviour and can describe it accurately.

AIM

This study set out to measure the tacit policies used by general practitioners in prescribing lipid lowering agents and to compare these with their stated policies.

METHOD

Effects of 13 separate cues on decisions to prescribe were examined. The cues included cholesterol levels and a number of associated risk factors for coronary heart disease. Doctors rated 130 imaginary cases presented by a computer. Thirty five general practitioners in the Plymouth area participated in the study. Their ages ranged from 31 to 55 years and all but four were men. The raw data in each case was a rating of the likelihood that the doctor would prescribe for the patient described. These were converted into statistical weightings by use of multiple linear regression. The pattern of (standardized) weights constituted the tacit policy for each doctor. Stated policies were measured in a subsequent interview by asking doctors to rate the influence of each cue.

RESULTS

Both tacit and stated policies diverged widely between different doctors. Most doctors overestimated the number of cues that had actually influenced their decisions, and many believed that they had taken into account associated factors for coronary heart disease when they had not. On lifestyle related risks doctors were generally less likely to treat overweight people and most stated this as their policy. Most were also less likely to treat smokers but some had the opposite policy. Those less likely to treat smokers were also less likely to treat obese patients. There was also considerable variation in the extent to which the doctors took account of the attitude of the patient to receiving treatment.

CONCLUSION

Doctors' policies are highly variable and particularly inconsistent in the treatment of smokers. Relevant risk factors may be ignored--even though they are understood--because the risk assessment involved is too psychologically complex a task to be performed intuitively. Decision aids and clear protocols are needed in this area.