Effect of pravastatin on serum lipids, apolipoproteins and lipoprotein (a) in patients with non-insulin dependent diabetes mellitus

Pravastatin

Pravastatin (Pravachol) is a competitive, reversible HMG-CoA reductase inhibitor that lowers serum cholesterol levels by inhibiting de novo cholesterol synthesis and has antiatherogenic effects that appear to be partially independent of its lipid-lowering effects. Pravastatin 10-40 mg/day produced significant reductions (vs baseline or placebo) in serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels in elderly patients (aged >or=60 or >or= 65 years) with hypercholesterolaemia or normal cholesterol levels. Serum triglyceride and high-density lipoprotein cholesterol levels also improved in some studies, but not in others. Coadministration of cholestyramine, another lipid-lowering agent, further enhanced the lipid-lowering effects of pravastatin in elderly patients. Data from the large, long-term (3-6 years) PROspective Study Of Pravastatin in the Elderly at Risk (PROSPER), Cholesterol And Recurrent Events trial (CARE) and Long term Intervention with Pravastatin in Ischaemic Disease (LIPID) trials demonstrated that pravastatin 40 mg/day reduces coronary events in elderly patients with hypercholesterolaemia or normal cholesterol levels, with or at high risk of developing coronary heart disease (CHD). In these trials, the incidence of death from CHD or the combined endpoint of death from CHD or nonfatal myocardial infarction was significantly lower in pravastatin than in placebo recipients. Pravastatin is well tolerated in the elderly, and adverse effects considered related to therapy are minimal. The most commonly occurring adverse events included gastrointestinal events, renal or genital system events, respiratory disorders, headaches and musculoskeletal pain.

CONCLUSION

Pravastatin effectively lowers serum TC and LDL-C levels and, as demonstrated in major clinical outcome trials, reduces coronary events in elderly patients with hypercholesterolaemia or normal cholesterol levels. Pravastatin is well tolerated and as such should be considered a first-line agents for primary or secondary prevention in older individuals with evident CHD or multiple risk factors for CHD.

Atorvastatin lowers lipoprotein(a) but not apolipoprotein(a) fragment levels in hypercholesterolemic subjects at high cardiovascular risk

The effect of statins on Lp(a) levels is controversial; furthermore, the potential action of statins on apo(a) fragmentation is indeterminate. We therefore determined the circulating levels of Lp(a) and of apo(a) fragments in hypercholesterolemic patients before and after treatment (6 weeks) with Atorvastatin 10 mg/day (A10) or Simvastatin 20 mg/day (S20). In a double blind study, hypercholesterolemic patients (n=391) at high cardiovascular risk (LDL-C>=4.13 mmol/l; TG<2.24 mmol/l; 34% with documented CHD; 45% hypertensive; and 29% current smokers) were assigned to treatment with A10 (n=199) or S20 (n=192). Plasma Lp(a) and apo(a) fragment levels (n=206) were measured prior to and after treatment. At baseline, A10 and S20 groups did not differ in plasma levels of lipids, Lp(a) (A10: 0.45+/-0.48 mg/ml, S20: 0.46+/-0.5), and apo(a) fragments (A10: 3.88+/-5.22 microg/ml; S20: 3.25+/-3), and equally in apo(a) isoform size (A10: 26+/-5 kr, S20: 25.5+/-5.3). After treatment, both statins significantly reduced Lp(a) levels (A10: 0.42+/-0.47 mg/ml, 6% variation, P<0.001; S20: 0.45+/-0.53 mg/ml, 0.02% variation, P=0.046). A10 and S20 did not significantly differ in their efficacy to lower Lp(a) levels. In a multivariate logistic regression analysis, the reduction of Lp(a) levels was independently associated with Lp(a) baseline concentration, but not to other variables, including LDL-C reduction. Plasma levels of apo(a) fragments were not modified by either statin. In conclusion, both A10 and S20 significantly lowered Lp(a), although this effect was of greater magnitude in atorvastatin-treated patients.

Treating dyslipidaemia in non-insulin-dependent diabetes mellitus -- a special reference to statins

Patients with non-insulin-dependent diabetes (NIDDM) have an increased incidence of ischaemic heart disease (IHD) when compared with nondiabetic subjects. In addition, they have a worse prognosis after their first myocardial infarction (MI). According to the recent USA recommendations, the threshold for initiation of dietary intervention in diabetic subjects is an LDL greater than 2.6 mmol/l, with the goal to achieve levels less than 2.6 mmol/l (100 mg/dl). This is also the threshold for initiation and treatment goal for pharmacological intervention in diabetic subjects, unless they are completely free of IHD, peripheral vascular disease or cerebrovascular disease and have no other IHD risk factors. In the latter circumstances, the threshold for treatment is an LDL greater than 3.38 mmol/l (130 mg/dl), with the goal to achieve levels less than 3.38 mmol/l. The HMG-CoA reductase inhibitors (statins) can improve the lipid profile effectively and safely in NIDDM. Results from post hoc analyses of diabetic subgroups in the large intervention trials suggest that some statins significantly reduce the risk for IHD-related mortality/morbidity. However, because these results are derived from secondary prevention trials, we cannot be sure if these benefits apply to all diabetic subjects or only to those who already have IHD. Nevertheless, it seems logical to assume that this benefit also applies to NIDDM patients who do not have IHD because they share a similar vascular risk as nondiabetic subjects who have IHD. Intervention trials using statins and fibrates, alone or in combination, in NIDDM are under way. In a few years these trials will provide definitive end-point-based evidence in this high-risk group of patients.

Pravastatin. A reappraisal of its pharmacological properties and clinical effectiveness in the management of coronary heart disease

Pravastatin is an HMG-CoA reductase inhibitor which lowers plasma cholesterol levels by inhibiting de novo cholesterol synthesis. Pravastatin produces consistent dose-dependent reductions in both total and low density lipoprotein (LDL)-cholesterol levels in patients with primary hypercholesterolaemia. Favourable changes in other parameters such as total triglyceride and high density lipoprotein (HDL)-cholesterol levels are generally modest. Combination therapy with other antihyperlipidaemic agents such as cholestyramine further enhances the efficacy of pravastatin in patients with severe dyslipidaemias. Available data suggest that pravastatin is effective in elderly patients and in patients with hypercholesterolaemia secondary to diabetes mellitus or renal disease. The benefit of cholesterol-lowering in terms of patient outcomes is currently an area of considerable interest. Recently completed regression studies (PLAC I, PLAC II, KAPS and REGRESS) show that pravastatin slows progression of atherosclerosis and lowers the incidence of coronary events in patients with mild to moderately severe hypercholesterolaemia and known coronary heart disease. Large scale primary (WOSCOPS) and secondary (CARE) prevention studies, moreover, demonstrate that pravastatin has beneficial effects on coronary morbidity and mortality. In WOSCOPS, all-cause mortality was reduced by 22%. Pravastatin is generally well tolerated by most patients (including the elderly), as evidenced by data from studies of up to 5 years in duration. As with other HMG-CoA reductase inhibitors, myopathy occurs rarely (< 0.1% of patients treated with pravastatin): approximately 1 to 2% of patients may present with raised serum levels of hepatic transaminases. Thus, with its favourable effects on cardiovascular morbidity/mortality and total mortality, pravastatin should be considered a first-line agent in patients with elevated cholesterol levels, multiple risk factors or coronary heart disease who are at high risk of cardiovascular morbidity.

Quantitation of apolipoprotein E

Quantitation of apoE has proved to be extremely useful in studies of the regulation of apoE synthesis and metabolism. Measurement of serum apoE and/or its distribution among the lipoprotein classes may have clinical utility, although this remains to be established. Some of the unique properties of apoE such as its genetic, chemical, and structural heterogeneity, its propensity to self-associate, and its ability to freely exchange on the surfaces of a wide variety of lipoprotein classes are factors that should be considered in measurements of apoE. The availability of commercial kits and reagents for human apoE quantitation make the development of apoE immunoassays readily achievable in most research and clinical laboratories.

Efficacy and safety of pravastatin in the treatment of patients with type I or type II diabetes mellitus and hypercholesterolemia

PURPOSE

Patients with type I and type II diabetes mellitus have an increased risk of coronary heart disease. In many diabetics, hypercholesterolemia is present and further exacerbates this risk. We investigated the efficacy and safety of pravastatin in the treatment of patients with type I or type II diabetes mellitus and hypercholesterolemia.

PATIENTS AND METHODS

In this 24-week, multi-center, double-blind, placebo-controlled study, 94 patients (45 men, 49 women), 18 to 70 years of age, with type I or type II diabetes mellitus and hypercholesterolemia (fasting plasma low-density lipoprotein cholesterol [LDL-C] levels > 150 mg/dL and above the 75th percentile for the US population by age and gender) were randomized to receive pravastatin 20 mg hs or matching placebo. Two patients were randomized to treatment with drug for every 1 randomized to placebo. The dose could be doubled after 10 weeks, and cholestyramine or colestipol could be added after 18 weeks, as needed, to attempt to lower the LDL-C levels to below the 50th percentile for the US population.

RESULTS

Significant reductions in LDL-C (-27.6%), total cholesterol (-22.1%), very-low-density lipoprotein cholesterol (-22.6%), and triglycerides (-12.8%) (P < or = 0.001 versus placebo for all reductions), and significant increases in high-density lipoprotein cholesterol (4.4%) (P < or = 0.05 versus placebo) were noted in the pravastatin treatment group (average dose 29.5 mg) at 16 weeks. The beneficial lipid-lowering effects of pravastatin were maintained throughout the 24 weeks of the study. Pravastatin was well tolerated, and the frequency of side effects was similar in the pravastatin and placebo groups. No clinically significant changes in the control of diabetes, as assessed by fasting blood glucose levels and glycosylated hemoglobin measurements, were seen during this study.

CONCLUSION

The results of this study demonstrate that pravastatin is well tolerated and effective in lowering total cholesterol and LDL-C in patients with type I or type II diabetes mellitus and hypercholesterolemia.

Changes in serum lipoprotein(a) in hyperlipidemic subjects undergoing long-term treatment with lipid-lowering drugs

Though the exact physiology and pathology of lipoprotein(a) [Lp(a)] remains unknown, it has been demonstrated that increased serum Lp(a) levels are correlated with an increased risk of atherosclerotic vascular disease. The effects of lipid-lowering drugs on Lp(a) levels is unclear because of inconsistencies between study designs. This study analyzes the effects of the commonly used lipid-lowering drugs pravastatin (PRAV), lovastatin (LOV), and cholestyramine (CHOL) on serum Lp(a) and other serum lipid levels in a parallel study design. Hyperlipidemic men (n = 32) were enrolled from three centers and treated for 48 weeks in a multicenter clinical trial using PRAV, LOV, CHOL, or a placebo (for the first 16 weeks only). Baseline serum low-density lipoproteins (LDL-C), high-density lipoproteins (HDL-C), and triglycerides were 199 +/- 38, 40 +/- 9, and 160 +/- 70 mg/dl, respectively. At the end of 48 weeks, serum plasma LDL-C declined in patients randomized to PRAV, LOV, and CHOL, respectively, by 31%, 29%, and 23% (all p < 0.001); HDL increased by 4%, 11%, and 11% (all p < 0.001); and TG changed by -16%, -28%, and +43% (all p < 0.001). Subjects in PRAV and LOV changed Lp(a) by 9% and 3%, respectively. Although there was an initial Lp(a) decline in the first 8 weeks of CHOL therapy (p < 0.05, ANOVA), this returned to baseline after 48 weeks. In this parallel study design PRAV, LOV, and CHOL are effective LDL-lowering medications with minimal effects on plasma Lp(a).

Lipoprotein(A): physiologic function, association with atherosclerosis, and effects of lipid-lowering drug therapy

OBJECTIVE

To review the structure and physiologic function of lipoprotein(a) [Lp(a)], review the association of Lp(a) with the development of atherosclerosis, and to critically evaluate the current literature regarding the effects of lipid-lowering drug therapy on Lp(a) serum concentrations.

DATA SOURCES

English language clinical and animal studies, abstracts, and review articles pertaining to Lp(a).

STUDY SELECTION AND DATA EXTRACTION

Relevant human and animal studies examining Lp(a)'s role in atherosclerosis and the effect of drug therapy on Lp(a) serum concentrations.

DATA SYNTHESIS

Possible physiologic functions and potential atherogenic mechanisms of Lp(a) are discussed. Evidence supporting the association of Lp(a) with atherosclerosis is presented. Studies evaluating the effects of lipid-lowering drug therapy on Lp(a) concentrations are reviewed and critiqued.

CONCLUSIONS

Lp(a) concentrations are correlated with the risk of atherosclerotic vascular disease (AVD) in both animals models and human studies. Drug therapies that have produced a consistent reduction in Lp(a) concentration include niacin alone or in combination with a bile acid sequestrant or neomycin. However, additional, larger studies are needed to evaluate the ability of drug therapies to specifically reduce elevated Lp(a) concentrations. Preliminary information suggests that reduction in Lp(a) concentrations may be associated with atherosclerotic plaque regression. Although drugs are available to lower Lp(a), one cannot conclude that lowering of Lp(a) is warranted until clinical trials demonstrating beneficial effects have been published.

A multi-centre study of the efficacy and safety of pravastatin in hypercholesterolaemic patients with non-insulin-dependent diabetes mellitus

A multi-centre, non-randomized clinical study of 12-months' duration was performed in 112 patients with hyperlipidaemia associated with non-insulin-dependent diabetes mellitus to evaluate the clinical efficacy and tolerability of pravastatin and to assess its effect on glycaemic control. Patients were eligible for this trial if they fulfilled the following criteria; a high plasma total cholesterol level greater than 220 mg/dl associated with stable glycaemic control for at least 3-months' observation period. On entry, patients received 10 mg pravastatin per day (5 mg twice daily) for 12 months. Clinical efficacy was evaluated in 108 patients. The results showed that pravastatin induced a significant decrease in serum cholesterol level mainly with LDL-cholesterol. Total cholesterol levels were decreased significantly from 275 +/- 3 mg/dl to 222 +/- 4 mg/dl within 3 months of the start of treatment, and LDL-cholesterol decreased from 192 +/- 4 mg/dl to 137 +/- 4 mg/dl. After 12 months' treatment, total cholesterol and LDL-cholesterol levels were 216 +/- 4 mg/dl (p < 0.001) and 137 +/- 5 mg/dl (p < 0.001), respectively. HDL-cholesterol levels were increased from 51 +/- 2 mg/dl to 56 +/- 2 mg/dl at 3 months (p < 0.001) and 55 +/- 2 mg/dl at 12 months (p < 0.01). Triglyceride concentrations were also decreased from 173 +/- 11 mg/dl to 156 +/- 13 mg/dl at 3 months and 137 +/- 10 mg/dl at 12 months (p < 0.01). Fasting plasma glucose and glycated haemoglobin levels were not affected by pravastatin. Adverse events observed in 5 cases were always mild and reversible. These results indicate a clinical usefulness of pravastatin with high compliance in patients with hyperlipidaemia associated with non-insulin-dependent diabetes mellitus.