Kenneth A. Schneider

Failure to reduce cholesterol as explanation for the limited efficacy of antihypertensive treatment in the reduction of CHD. Examination of the evidence from six hypertension intervention trials.

SummaryOver the past 6 years, major hypertension intervention studies in Europe, Australia, and the USA have shown disappointing results in the prevention of coronary heart disease (CHD) in spite of adequate treatment and good compliance. Recently, it has become increasingly clear that hypertensives with or without treatment display higher cholesterol levels than normotensive persons. The present review examines cholesterol levels in six intervention studies, none of which offered dietary or drug therapy for hypercholesterolemic patients. The Oslo study and the British MRC Trial reported very high average cholesterol levels and both showed no protection from CHD through intensive therapy in comparison to control patients. The Australian and the American MRFIT studies produced evidence for reduced coronary mortality among hypertensives with low in contrast to those with high cholesterol levels. The European Working Party showed indirectly that patients with marked reduction in blood pressureand cholesteral had a significantly lower cardiac mortality compared to placebo-treated patients. The IPPPSH study found that increasing cholesterol levels in hypertensives under beta blockeror diuretic therapy increased the risk of myocardial infarction.Failure to reduce cholesterol in hypertensive patients apparently is a major reason for the limited efficacy of antihypertensive treatment in the reduction of CHD.

Failure to Reduce Cholesterol as Explanation for the Limited Efficacy of Antihypertensive Treatment in the Reduction of Coronary Heart Disease

The recent experience of six large trials of antihypertensive therapy has not clearly demonstrated any beneficial effect on the prevention of coronary heart disease (CHD). The data from the HDFP study have been analyzed by three cholesterol strata at baseline. The higher the baseline cholesterol levels, the greater the risk for CHD. In hypertensive patients, the slope of the relationship between cholesterol and CHD event rate was examined. There is indication of an increase of about 6 CHD events per 1,000 patients for each 50 mg/mdl increase in cholesterol (p less than 0.05). This population was further divided into those with major end organ damage (EOD) and those without EOD at baseline. In patients who had no EOD, examination of baseline cholesterol level and 5-year CHD death rates indicates a similar relationship. In contrast, the lack of correlation between baseline cholesterol level and CHD death rates in those hypertensives with EOD, suggests the need to reduce hypercholesterolemia before EOD occurs.

Influence of dietary sodium restriction on lipid metabolism.

SummaryThe possible increase in total and low-density lipoprotein cholesterol following severe restriction of dietary NaCl was reported in 1990 and and 1991 from three experiments, one in the United States and two in Germany. Each of these experiments lasted only 1 week. To evaluate the clinical side effects we analyzed data collected from patients who completed a course of NaCl-restricted weight reduction at the Duke Diet and Fitness Center. Observations of lipid changes are not available for periods of less than 3 weeks; however, we were able to collect data on lipid and lipoprotein changes from 556 participants 25 days after they were referred for weight reduction. Total cholesterol, low-density lipoprotein cholesterol, and triglyceride levels returned to normal in the majority of obese patients. In our slightly longer observation period in patients on a 1000 mg NaCl restricted diet we found no evidence of hyperlipidemic side effects. We believe that the hyperlipidemia resulting from severe sodium restriction in non-hypertensive, normal-weight individuals is not relevant to the problem of nonpharmacological and diuretic treatment of obese hypertensive patients. In clinically healthy, normal-weight, normotensive individuals severe salt restriction serves no practical or therapeutic purpose.