Indications for cholesterol-lowering medication: comparison of risk-assessment methods

BACKGROUND

Recommendations for the prescription of lipid-lowering drugs emphasise the importance of an assessment of absolute coronary heart disease (CHD) risk based on all risk factors, rather than simply the serum cholesterol concentration. If, however, the methods recommended for risk assessment are inaccurate, recommended prescribing will not occur. We compared several sets of guidelines for such treatment in a series of patients referred to a lipid clinic, to assess the difference in degree of risk of CHD at which lipid-lowering medication is recommended by each set of guidelines.

METHODS

For a series of 570 patients (50% men) without pre-existing clinical evidence of atherosclerosis referred to a lipid clinic, we compared the algorithms, charts, and tables used by the US National Cholesterol Education Program (NCEP), the joint guidelines of the European Society of Cardiology, the European Atherosclerosis Society, and the European Society of Hypertension, and the report of the UK Standing Medical Advisory Committee with the Framingham risk equation programmed into a computer.

FINDINGS

In 386 patients for whom the NCEP and UK guidelines could be compared, 62% of the men and 72% of the women met NCEP criteria for lipid-lowering medication, whereas only 9% of the men and less than 1% of the women met the UK criteria. The Framingham equation estimated a CHD risk of more than 3% per year in 22% of the men and 7% of the women, which shows that the UK tables underestimated CHD risk. European guidelines could be applied to only 261 patients, and were reasonably accurate in assessment of a CHD risk of 2% per year.

INTERPRETATION

Guidelines for the use of statin treatment in patients with CHD differ in their assessment of CHD risk. The method of risk assessment recommended in future guidelines for CHD prevention should be critically tested in relevant groups of patients.

Effects of two different fibric acid derivatives on lipoproteins, cholesteryl ester transfer, fibrinogen, plasminogen activator inhibitor and paraoxonase activity in type IIb hyperlipoproteinaemia

We have investigated the effects of two fibric acid derivatives, bezafibrate mono (400 mg daily) and gemfibrozil (600 mg b.d.), in 29 patients with type IIb hyperlipoproteinaemia. All patients received placebo and each drug for 8 weeks in randomised order in a double-blind, cross-over study designed to evaluate any different effects of the drugs on serum lipoproteins, cholesteryl ester transfer protein (CETP), cholesteryl ester transfer activity (CETA), plasma fibrinogen, plasminogen activator inhibitor-I (PAI-1) or paraoxonase. Serum cholesterol decreased (P < 0.05) with gemfibrozil, but the effect of bezafibrate on serum cholesterol did not achieve statistical significance (placebo 8.34 +/- 1.05 (mean +/- S.D.), gemfibrozil 7.70 +/- 1.23 and bezafibrate 7.8 +/- 1.37 mmol/l). Both drugs decreased the serum triglyceride concentration (both P < 0.001) (placebo 4.39 (3.13-5.75) (median (interquartile range)), bezafibrate 2.26 (1.89-3.89) and gemfibrozil 2.00 (1.30-3.30) mmol/l) and very low density lipoprotein (VLDL) cholesterol (both P < 0.001) (placebo 1.18 (0.74-2.30), bezafibrate 0.59 (0.34-0.85) and gemfibrozil 0.48 (0.34-0.68) mmol/l). Discontinuous gradient ultracentrifugation (DGU) revealed that Sf 60-400 (large VLDL) decreased by more than 50% and Sf 20-60 (small VLDL) by more than 30% with each of the drugs (both P < 0.001), neither of which affected the composition of these lipoproteins. Gemfibrozil decreased the concentration of Sf 12-20 lipoprotein (intermediate density lipoprotein; IDL) by 23% (P < 0.01), whereas the effect of bezafibrate on this lipoprotein did not achieve statistical significance. Neither drug altered the concentration of apolipoprotein B or of total Sf 0-12 lipoproteins (low density lipoprotein, (LDL)). Both, however, significantly increased the quantity of free cholesterol in Sf 0-12 lipoproteins (P < 0.05). Overall the concentration of triglycerides decreased significantly in all lipoproteins isolated by DGU (Sf 0-12, Sf 12-20, Sf 20-60, Sf 60-400) on gemfibrozil treatment, but only in Sf 20-60 and Sf 60-400 on bezafibrate (all P < 0.05). Both drugs also increased serum high density lipoprotein (HDL) cholesterol (placebo 1.15 +/- 0.29, bezafibrate 1.27 +/- 0.38 (P < 0.01) and gemfibrozil 1.26 +/- 0.49 (P < 0.05) mmol/l) and HDL3 cholesterol concentration (placebo 0.59 +/- 0.12, bezafibrate 0.72 +/- 0.23 (P < 0.001) and gemfibrozil 0.70 +/- 0.24 (P < 0.01) mmol/l). Serum apolipoprotein A1 (apo A1) was increased (P < 0.05) by bezafibrate compared to gemfibrozil (placebo 103 +/- 26, bezafibrate 111 +/- 28 and gemfibrozil 102 +/- 25 mg/dl) and CETA from HDL to VLDL and LDL was decreased (P < 0.05) by bezafibrate compared to placebo, but the apparent decrease with gemfibrozil did not achieve statistical significance (placebo 39.6 +/- 17.7, bezafibrate 32.3 +/- 14.7 and gemfibrozil 33.8 +/- 15.0 nmol/ml/h). Neither drug affected the circulating concentration of CETP. Plasma fibrinogen was increased (P < 0.05) by gemfibrozil (placebo 4.16 (3.38-4.71) and gemfibrozil 4.65 (4.05-5.77) g/l) and was significantly lower (P < 0.001) on bezafibrate (3.60 (3.18-4.54) g/l) than on gemfibrozil treatment. There was a significant (P < 0.05) increase in PAI-1 activity with bezafibrate and a similar trend with gemfibrozil (placebo 41.2 (25.6-64.5), bezafibrate 50.5 (35.1-73.9) and gemfibrozil 48.5 (31.5-5.4 U/l). Neither fibrate influenced plasma concentrations of PAI-1 nor were the activities of lecithin:cholesterol acyl transferase or paraoxonase affected. The major difference in the action of the two drugs on lipoprotein metabolism was the greater effect of gemfibrozil in decreasing the overall serum concentration of Sf 12-20 lipoproteins and the triglycerides in Sf 12-20 and 0-12 lipoproteins. Bezafibrate, however, increased serum apo A1 concentration and significantly decreased CETA. The two drugs also had different effects on the plasma fibrinogen levels, which increased with gemfibrozil and tended to decrea

Effects of a new fish oil concentrate on plasma lipids and lipoproteins in patients with hypertriglyceridaemia

OBJECTIVES

The effect of a fish oil preparation, K-85, in which the omega-3 fatty acid content was concentrated to 92% of total fat, on serum lipid and lipoprotein concentrations was investigated in patients with primary hypertriglyceridaemia.

DESIGN

The study was a randomized, double-blind, placebo-controlled study.

SETTING

Seven centres participated in the study, five secondary referral centres and two general practices.

SUBJECTS

Men and women aged 18-70 years with fasting serum triglyceride concentrations between 2 and 10 mmol/l and fasting serum cholesterol concentrations > 5.2 mmol/l were studied. Patients with diabetes mellitus, hypothyroidism, serious illness in the previous 3 months or severe concurrent illness were excluded from the study, as were drug or alcohol abusers and pregnant and lactating women. Ninety-five subjects entered the study, 79 completed the study.

INTERVENTIONS

Patients were randomized to receive K-85 2 g twice daily or corn oil 2 g twice daily for 14 weeks.

MAIN OUTCOME MEASUREMENTS

The serum concentrations of triglycerides and cholesterol, very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), high-density lipoprotein (HDL) and lipoprotein (a). Fasting blood glucose and blood pressure.

RESULTS

Serum triglycerides and VLDL-cholesterol were significantly lower in the group treated with K-85 than in the placebo group after 6, 10 and 14 weeks (all P < 0.01) and there was a decrease in the serum triglyceride concentration from 3.99 (2.94-9.47) to 2.87 (1.2-9.93) mmol/l (P < 0.001) and in VLDL-cholesterol from 1.47 (0.77-3.63) to 1.12 (0.21-3.67) mmol/l (P < 0.01) in patients receiving K-85. Serum HDL-cholesterol increased from 0.98 (0.95-1.01) to 1.11 (1.07-1.15) mmol/l (P < 0.01) in the patients with type IV hyperlipoproteinaemia but did not change in those with type IIb. Serum LDL-cholesterol, lipoprotein (a) and fasting blood glucose were unaffected by K-85. Diastolic blood pressure decreased from 86 +/- 11 to 80 +/- 12 mmHg (P < 0.02) and was also lower than in the placebo group (P < 0.05). The corn oil placebo did not affect any of the parameters.

CONCLUSION

K-85 is effective in lowering serum triglycerides and VLDL in patients with primary hypertriglyceridaemia and may have utility as a triglyceride-lowering agent.

Increased transfer of cholesteryl esters from high density lipoproteins to low density and very low density lipoproteins in patients with angiographic evidence of coronary artery disease

Cholesterol esterification, transfer of cholesteryl esters from high density lipoproteins to very low density and low density lipoproteins (VLDL/LDL) and the composition of lipoproteins isolated by density gradient ultracentrifugation have been investigated in 18 men with angiographic evidence of severe coronary artery disease and in 27 healthy men without coronary artery disease. Patients had significantly higher serum cholesterol (P < 0.001), serum triglycerides (P < 0.02) and lower high density lipoprotein cholesterol (HDL) (P < 0.04) compared with healthy men. The transfer of cholesteryl ester from HDL to VLDL and LDL was 27.8 +/- 12.2 nmol/ml per h (mean +/- S.D.) in patients and was significantly higher than the value of 17.8 +/- 6.5 nmol/ml per h obtained in healthy men (P < 0.003) or 17.1 +/- 7.6 nmol/ml per h) in 16 controls (P < 0.03) with similar serum cholesterol and triglyceride concentrations. Lipoprotein protein concentrations were significantly higher in LDL (P < 0.05) and small VLDL (P < 0.01) in patients. In addition, patient LDL and large VLDL contained more free cholesterol than matched controls (P < 0.01, P < 0.05, respectively). This was reflected in the increased free cholesterol/phospholipid ratio (a measure of lipoprotein surface composition) in LDL (P < 0.002). These findings indicate that patients with established coronary artery disease have increased transfer of cholesteryl ester from HDL to VLDL and LDL, which is independent of serum triglyceride concentrations. This increased transfer of cholesteryl ester may be a result of the increased free cholesterol content of very low density lipoproteins.

Serum lipoprotein (a) concentrations in patients undergoing continuous ambulatory peritoneal dialysis

Lipoprotein (a) is a subspecies of low-density lipoprotein which possesses as part of its protein moiety a mutant form of plasminogen termed apolipoprotein (a), and which may be closely related to the risk of ischaemic heart disease and cerebral infarction. We have investigated the serum concentrations of lipoprotein (a) and other lipoproteins in 24 male patients on CAPD and compared them to healthy men (n = 100) and to age-matched healthy controls (n = 38). The most striking finding was a substantial elevation of serum lipoprotein (a) in CAPD patients in whom it was 46.9 (2.2-168) mg/dl (median and range) compared to 9.0 (< 0.6-87.4) mg/dl in healthy control group and 6.7 (< 0.6-84.2) mg/dl in age-matched controls (both P < 0.001). Patients, when compared to healthy men, also had significantly increased serum triglycerides (median and range, 1.94 (0.55-8.00) versus 1.24 (0.36-4.40) mmol/l; P < 0.001), very-low-density lipoprotein cholesterol (median and range, 0.98 (0.10-3.71) versus 0.46 (0.10-1.17) mmol/l; P < 0.001), and lower-high-density lipoprotein cholesterol (mean +/- 1 SD, 1.26 +/- 0.29 versus 1.35 +/- 0.31 mmol/l). Of these, however, only the difference in very-low-density lipoprotein cholesterol remained statistically significant (P < 0.001) in comparison to age-matched controls. The marked elevation of serum lipoprotein (a) in patients on CAPD may be due to increased hepatic synthesis as a consequence of the substantial amounts of plasma proteins lost in the dialysate. Elevated serum lipoprotein (a) concentrations in CAPD patients may contribute to their risk of coronary artery disease.

Effects of treatment of hypertriglyceridaemia with gemfibrozil on serum lipoproteins and the transfer of cholesteryl ester from high density lipoproteins to low density lipoproteins

Lipoprotein composition and cholesterol esterification, before and after treatment with gemfibrozil, have been examined in the fasting and postprandial state in nine patients with primary hypertriglyceridaemia who participated in a double-blind, placebo controlled study. After 8 weeks of treatment fasting serum triglycerides were reduced significantly from 6.05 mmol/l (range 2.48-10.99 mmol/l) to 1.76 mmol/l (range 1.16-11.90 mmol/l) (P less than 0.001). This was mainly due to a decrease in the triglyceride content of the Sf 12-20, 60-400 and Sf greater than 400 lipoprotein fractions (P less than 0.05). The Sf 0-12 fraction showed an increase in cholesteryl ester, free cholesterol, phospholipids and protein. Consistent with these findings there was a net increase in the mass concentration of the Sf 0-12 fraction (P less than 0.05) and a decrease in that of small very low density lipoproteins (Sf 20-60) (P less than 0.05). In the 8 patients in whom it was measured there was a 40% reduction in the rate at which cholesteryl esters derived from radiolabelled-free cholesterol appeared in very low density lipoprotein (VLDL) and low density lipoprotein (LDL) measured in an in vitro system (P less than 0.02), but serum lecithin:cholesterol acyl transferase (LCAT) activity was unchanged. At the end of each treatment phase (placebo or gemfibrozil) patients were given a mixed meal containing 100 g of fat. Treatment with gemfibrozil resulted in a reduction in serum triglyceride concentrations at all time points for at least 5 h after the meal (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)