Pravastatin treatment in combined hyperlipidaemia. Effect on plasma lipoprotein levels and size

Pravastatin for lowering lipids

BACKGROUND

A detailed summary and meta-analysis of the dose-related effect of pravastatin on lipids is not available.

OBJECTIVES

Primary objective To assess the pharmacology of pravastatin by characterizing the dose-related effect and variability of the effect of pravastatin on the surrogate marker: low-density lipoprotein (LDL cholesterol). The effect of pravastatin on morbidity and mortality is not the objective of this systematic review. Secondary objectives • To assess the dose-related effect and variability of effect of pravastatin on the following surrogate markers: total cholesterol; high-density lipoprotein (HDL cholesterol); and triglycerides. • To assess the effect of pravastatin on withdrawals due to adverse effects.

SEARCH METHODS

The Cochrane Hypertension Information Specialist searched the following databases for randomized controlled trials (RCTs) up to September 2021: CENTRAL (2021, Issue 8), Ovid MEDLINE, Ovid Embase, Bireme LILACS, the WHO International Clinical Trials Registry Platform, and ClinicalTrials.gov. We also contacted authors of relevant papers regarding further published and unpublished work. The searches had no language restrictions.

SELECTION CRITERIA

Randomized placebo-controlled trials evaluating the dose response of different fixed doses of pravastatin on blood lipids over a duration of three to 12 weeks in participants of any age with and without evidence of cardiovascular disease.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility criteria for studies to be included, and extracted data. We entered lipid data from placebo-controlled trials into Review Manager 5 as continuous data and withdrawal due to adverse effects (WDAEs) data as dichotomous data. We searched for WDAEs information from all trials. We assessed all trials using Cochrane's risk of bias tool under the categories of sequence generation, allocation concealment, blinding, incomplete outcome data, selective reporting, and other potential biases.

MAIN RESULTS

Sixty-four RCTs evaluated the dose-related efficacy of pravastatin in 9771 participants. The participants were of any age, with and without evidence of cardiovascular disease, and pravastatin effects were studied within a treatment period of three to 12 weeks. Log dose-response data over the doses of 5 mg to 160 mg revealed strong linear dose-related effects on blood total cholesterol and LDL cholesterol, and a weak linear dose-related effect on blood triglycerides. There was no dose-related effect of pravastatin on blood HDL cholesterol. Pravastatin 10 mg/day to 80 mg/day reduced LDL cholesterol by 21.7% to 31.9%, total cholesterol by 16.1% to 23.3%,and triglycerides by 5.8% to 20.0%. The certainty of evidence for these effects was judged to be moderate to high. For every two-fold dose increase there was a 3.4% (95% confidence interval (CI) 2.2 to 4.6) decrease in blood LDL cholesterol. This represented a dose-response slope that was less than the other studied statins: atorvastatin, rosuvastatin, fluvastatin, pitavastatin and cerivastatin. From other systematic reviews we conducted on statins for its effect to reduce LDL cholesterol, pravastatin is similar to fluvastatin, but has a decreased effect compared to atorvastatin, rosuvastatin, pitavastatin and cerivastatin. The effect of pravastatin compared to placebo on WADES has a risk ratio (RR) of 0.81 (95% CI 0.63 to 1.03). The certainty of evidence was judged to be very low.

AUTHORS' CONCLUSIONS

Pravastatin lowers blood total cholesterol, LDL cholesterol and triglyceride in a dose-dependent linear fashion. This review did not provide a good estimate of the incidence of harms associated with pravastatin because of the lack of reporting of adverse effects in 48.4% of the randomized placebo-controlled trials.

Statin therapy and lipoprotein(a) levels: a systematic review and meta-analysis

AIMS 

Lipoprotein(a) [Lp(a)] is a causal and independent risk factor for cardiovascular disease (CVD). People with elevated Lp(a) are often prescribed statins as they also often show elevated low-density lipoprotein cholesterol (LDL-C) levels. While statins are well-established in lowering LDL-C, their effect on Lp(a) remains unclear. We evaluated the effect of statins compared to placebo on Lp(a) and the effects of different types and intensities of statin therapy on Lp(a).

METHODS AND RESULTS 

We conducted a systematic review and meta-analysis of randomized trials with a statin and placebo arm. Medline and EMBASE were searched until August 2019. Quality assessment of studies was done using Cochrane risk-of-bias tool (RoB 2). Mean difference of absolute and percentage changes of Lp(a) in the statin vs. the placebo arms were pooled using a random-effects meta-analysis. We compared effects of different types and intensities of statin therapy using subgroup- and network meta-analyses. Certainty of the evidence was determined using GRADE (Grading of Recommendations, Assessment, Development, and Evaluation). Overall, 39 studies (24 448 participants) were included. Mean differences (95% confidence interval) of absolute and percentage changes in the statin vs. the placebo arms were 1.1 mg/dL (0.5-1.6, P < 0.0001) and 0.1% (-3.6% to 4.0%, P = 0.95), respectively (moderate-certainty evidence). None of the types of statins changed Lp(a) significantly compared to placebo (very low- to high-certainty evidence), as well as intensities of statin therapy (low- to moderate-certainty evidence).

CONCLUSION 

Statin therapy does not lead to clinically important differences in Lp(a) compared to placebo in patients at risk for CVD. Our findings suggest that in these patients, statin therapy will not change Lp(a)-associated CVD risk.

Clinical importance and therapeutic modulation of small dense low-density lipoprotein particles

The National Cholesterol Education Programme Adult Treatment Panel III accepted the predominance of small dense low-density lipoprotein (sdLDL) as an emerging cardiovascular disease (CVD) risk factor. Most studies suggest that measuring low-density lipoprotein (LDL) particle size, sdLDL cholesterol content and LDL particle number provides additional assessment of CVD risk. Therapeutic modulation of small LDL size, number and distribution may decrease CVD risk; however, no definitive causal relationship is established, probably due to the close association between sdLDL and triglycerides and other risk factors (e.g., high-density lipoprotein, insulin resistance and diabetes). This review addresses the formation and measurement of sdLDL, as well as the relationship between sdLDL particles and CVD. The effect of hypolipidaemic (statins, fibrates and ezetimibe) and hypoglycaemic (glitazones) agents on LDL size and distribution is also discussed.

The Clinical Relevance of Low-Density-Lipoproteins Size Modulation by Statins

The predominance of small, dense low density lipoproteins (LDL) has been accepted as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Treatment Panel III; in fact, LDL size seems to be an important predictor of cardiovascular events and progression of coronary heart disease. Several studies have also shown that the therapeutical modulation of LDL size is of great benefit in reducing the risk of cardiovascular events. Hypolipidemic treatment is able to alter LDL subclass distribution and statins are currently the most widely used lipid-lowering agents. Statins are potent inhibitors of hydroxy-methyl-glutaryl-coenzyme A reductase, the rate-limiting enzyme in hepatic cholesterol synthesis and are the main drugs of choice for the treatment of elevated plasma LDL cholesterol concentrations. Statins potentially lower all LDL subclasses (e.g., large, medium and small particles); thus, their net effect on LDL subclasses or size is often only moderate. However, a strong variation has been noticed among the different agents: analyses of all published studies suggest a very limited role of pravastatin and simvastatin in modifying LDL size and their subclasses, while fluvastatin and atorvastatin seem to be much more effective agents. Finally, rosuvastatin, the latest statin molecule introduced in the market, seems to be promising in altering LDL subclasses towards less atherogenic particles.

Low-density lipoprotein size and cardiovascular risk assessment

A predominance of small, dense low-density lipoproteins (LDL) has been accepted as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Treatment Panel III. LDL size seems to be an important predictor of cardiovascular events and progression of coronary heart disease and evidences suggests that both quality (particularly small, dense LDL) and quantity may increase cardiovascular risk. However, other authors have suggested that LDL size measurement does not add information beyond that obtained by measuring LDL concentration, triglyceride levels and HDL concentrations. Therefore, it remains debatable whether to measure LDL particle size in cardiovascular risk assessment and, if so, in which categories of patient. Therapeutic modulation of LDL particle size or number appears beneficial in reducing the risk of cardiovascular events, but no clear causal relationship has been shown, because of confounding factors, including lipid and non-lipid variables. Studies are needed to investigate the clinical significance of LDL size measurements in patients with coronary and non-coronary forms of atherosclerosis; in particular, to test whether LDL size is associated with even higher vascular risk, and whether LDL size modification may contribute to secondary prevention in such patients.

Efficacy of a Low Dose of Pitavastatin Compared with Atorvastatin in Primary Hyperlipidemia: Results of a 12-week, open label study

BACKGROUND

Pitavastatin has a potent cholesterol-lowering action. The clinical efficacy and safety of a low dose, 1 mg, of pitavastatin were examined.

METHODS

The effect of 12 weeks' treatment with pitavastatin 1 mg in an open label, non-randomized trial involving 137 patients with hypercholesterolemia as compared with treatment with atorvastatin 10 mg.

RESULTS

Total cholesterol, low-density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol and triglyceride (TG) levels at baseline did not differ between the two groups. At follow-up, there were no significant differences in total cholesterol, LDL cholesterol and HDL cholesterol levels between the groups. The TG levels at follow-up were higher in the pitavastatin group than atorvastatin group (p < 0.01). In patients with hyperlipidemia type IIa, TG levels at follow-up were lower in the atorvastatin subgroup (p < 0.01). However, there was no significant difference in TG levels at follow-up between the two subgroups in patients with hyperlipidemia type IIb.

CONCLUSION

Pitavastatin 1 mg daily was safe and efficacious in reducing LDL cholesterol levels as compared with atorvastatin 10 mg daily. Further randomized comparative studies are needed to clarify the effect of a low dose of pitavastatin.

Effects of Atorvastatin on Low-Density Lipoprotein Cholesterol Phenotype and C-Reactive Protein Levels in Patients Undergoing Long-Term Dialysis

STUDY OBJECTIVES

To determine the effects of atorvastatin on low-density lipoprotein cholesterol (LDL) particle size and C-reactive protein (CRP) concentrations in patients undergoing long-term hemodialysis. Another objective was to compare the effects of atorvastatin on lipoprotein profiles as determined by direct versus indirect assessment of lipoprotein composition.

DESIGN

Randomized, parallel-group substudy.

SETTING

Two university-affiliated outpatient hemodialysis centers.

PATIENTS

Nineteen patients with LDL levels above 100 mg/dl and with at least two cardiovascular risk factors.

INTERVENTION

Patients were randomized in a 1:1 ratio to atorvastatin 10 mg/day or no treatment (control) for 20 weeks.

MEASUREMENTS AND MAIN RESULTS

We compared the differences between LDL particle size and CRP levels at baseline and 20 weeks in the atorvastatin versus control groups. Baseline demographic characteristics were similar between the two groups. Atorvastatin therapy was associated with no change in mean LDL particle size (p=0.23) and with a 90% decrease in mean CRP level (p=0.52). When evaluated by standard chemical analysis, atorvastatin therapy reduced total cholesterol levels by 29% (p=0.025) and resulted in nonsignificant reductions in LDL, high-density lipoprotein cholesterol, and triglyceride levels. Treatment with atorvastatin was not associated with significant changes in lipoprotein profile as determined by nuclear magnetic resonance (NMR) spectroscopy.

CONCLUSION

Treatment with atorvastatin did not affect LDL particle size but was associated with a sizable, yet nonsignificant, reduction in CRP concentrations. The drug had variable effects on lipoprotein concentrations as determined by chemical and NMR analytical methods. A larger study is necessary to provide definitive information on the effects of atorvastatin on LDL phenotype and CRP in patients with kidney disease.

Effect of lipid-lowering drug therapy on small-dense low-density lipoprotein

OBJECTIVE

To review the effects of lipid-lowering therapy on small-dense low-density lipoprotein cholesterol (sdLDL-C).

DATA SOURCES

Literature was obtained from MEDLINE (1989-September 2004) and references of selected articles. Key search terms included small-dense LDL-C and lipid-lowering drug therapy.

DATA SYNTHESIS

Statins, fibrates, and niacin have demonstrated favorable effects on sdLDL-C, especially among patients with mixed dyslipidemia or hypertriglyceridemia. These effects include a reduction of sdLDL-C and/or a shift to the larger, less atherogenic LDL-C.

CONCLUSIONS

Data suggest that statins, fibrates, and niacin are effective at reducing concentrations of sdLDL-C and possibly normalizing LDL-C subclasses.

Effect of atorvastatin on the concentration, relative distribution, and chemical composition of lipoprotein subfractions in patients with dyslipidemias of type IIA and IIB

The authors investigated the effect of atorvastatin (40 mg qd) on low-density lipoprotein (LDL) particle distribution in patients with dyslipidemias of type IIA (n = 55) and IIB (n = 21). Atorvastatin therapy induced a significant decrease in total and LDL cholesterol in both patient groups. A significant reduction in triglyceride values, which was more profound in type IIB patients, was also observed. In type IIA patients, LDL-3 was the predominant subfraction. Atorvastatin therapy induced a significant reduction in total LDL mass in this group of patients that was mainly due to the reduction in large and intermediate subspecies (LDL-1 to LDL-3), whereas the mass of dense LDL particles (LDL-4 and LDL-5) remained unchanged. As a consequence, the percentage contribution of dense subfractions to the total LDL mass increased significantly after atorvastatin therapy. The dense LDL-4 subfraction was the predominant one in type IIB patients. In this group, atorvastatin therapy resulted in a significant reduction in the total LDL mass, which was due to the reduction in all LDL subfractions. Thus, the percentage mass distribution of LDL particles remained unaffected. These results suggest that the effect of atorvastatin on LDL subfractions is affected by the underlying genetic defect.

Effects of pravastatin treatment on lipoprotein subclass profiles and particle size in the PLAC-I trial

Lipoprotein subclass analyses may facilitate coronary heart disease (CHD) risk stratification and provide insight into the cardioprotective benefits of statins (3-hydroxymethylglutaryl-coenzyme A reductase inhibitors). This study evaluated the influence of pravastatin on lipoprotein subclass profiles to determine whether subjects with predominantly large LDL (LDL size >20.5 nm) or small LDL (LDL size < or =20.5 nm) at baseline differ in responsiveness to drug treatment. Frozen plasma specimens were analyzed from a subset of participants in the Pravastatin Limitation of Atherosclerosis in the Coronaries (PLAC-I) trial at baseline and after treatment for 6 months with pravastatin (n=154) or placebo (n=138). Lipids were measured by standard chemical methods and lipoprotein subclasses by nuclear magnetic resonance (NMR) spectroscopy. Pravastatin-induced changes in lipid levels were similar in subjects with large or small LDL at baseline. Levels of the most abundant LDL subclass were preferentially lowered by pravastatin, resulting in an increase in average LDL size for those with a predominance of small LDL. High-risk CHD subjects with small LDL particles gain at least as much pharmacological benefit from pravastatin as those with large LDL, as evidenced by reductions in the numbers of total and small LDL particles, and increases in average LDL and HDL particle size.

Developing a clinical strategy for cholesterol management in an era of unanswered questions

Recent clinical trials have supported the use of cholesterol-lowering therapies to reduce cardiovascular events. Despite these results, a number of unanswered questions remain, including the appropriate intensity of lipid-lowering therapy and the role of high-density lipoprotein cholesterol and/or triglycerides in cardiovascular risk assessment and reduction. In addition, the optimal treatment strategies for women, the elderly, and patients with diabetes are more difficult to determine, as these groups have comprised a minority of subjects in prior trials. Studies in progress will provide guidance toward effective treatment of these populations, the appropriate degree of lipid-lowering therapy, and the role of estrogen replacement therapy in postmenopausal women. In the interim, a clinical strategy incorporating the lessons of recent clinical evidence is suggested.

Plasma lipoprotein distribution and lipid transfer activities in patients with type IIb hyperlipidemia treated with simvastatin

The aim of the present study was to search in type IIb hyperlipidemic patients for putative concomitant effects of simvastatin on the physicochemical characteristics of low density lipoproteins (LDL) and high density lipoproteins (HDL), as well as on the activities of the cholesteryl ester transfer protein (CETP) and the phospholipid transfer protein (PLTP) that were determined in both endogenous lipoprotein-dependent and endogenous lipoprotein-independent assays. In a double-blind, randomized trial, patients received either placebo (one tablet/day; n = 12) or simvastatin (20 mg/day; n = 12) for a period of 8 weeks after a 5-week run-in period. Simvastatin, unlike placebo, reduced the lipid and apolipoprotein B contents of the most abundant LDL-1, LDL-2, and LDL-3 subfractions without inducing significant changes in the overall size distribution of LDL and HDL. Whereas simvastatin significantly increased PLTP activity in an endogenous lipoprotein-dependent assay (P < 0.01), no variation was observed in a lipoprotein-independent assay. Simvastatin significantly decreased plasma CETP activity in an endogenous lipoprotein-dependent assay (P < 0.01), and the reduction in plasma cholesteryl ester transfer rates was explained by a 16% drop in CETP mass concentration (P < 0.01). In contrast, the specific activity of CETP was unaffected by the simvastatin treatment reflecting at least in part the lack of significant alteration in plasma triglyceride-rich lipoprotein acceptors. The simvastatin-induced changes in plasma CETP mass levels correlated positively with changes in plasma CETP activity (r = 0.483, P = 0.0561), in total cholesterol levels (r = 0.769; P < 0.01), and in LDL-cholesterol levels (r = 0.736; P < 0.01). Whereas the observations suggest that simvastatin might exert concomitant beneficial effects on plasma CETP and LDL levels, neither plasma cholesteryl ester transfer activity nor plasma phospholipid transfer activity appeared as the main determinants of the LDL and HDL distribution profiles in type IIb hyperlipidemic patients.

Role of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors ("statins") in familial combined hyperlipidemia

Familial combined hyperlipidemia (FCHL) is a heterogeneous genetic disorder characterized by multiple lipoprotein phenotypes. The genetic defect is unknown, although linkage to the region of the apolipoprotein (apo) A-I-apoC-III-apo A-IV gene cluster on chromosome 11 has been suggested. The metabolic abnormality in many affected individuals is overproduction of apoB-containing lipoproteins causing elevated levels of plasma cholesterol, triglycerides, or both. Low levels of high-density lipoprotein (HDL) cholesterol and an abundance of dense low-density lipoprotein (LDL) particles are other features contributing to the high association of this disorder with premature coronary artery disease. Many affected individuals need drug therapy to lower their lipid levels. The hepatic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, or "statins," offer a potent therapeutic option in patients with FCHL. These drugs significantly decrease levels of total cholesterol, LDL cholesterol, and apoB, although their effects on HDL cholesterol and triglycerides are limited. The mechanisms by which statins exert their beneficial effects in patients with FCHL remain controversial. We studied 7 patients with FCHL and 5 genetically uncharacterized patients with mixed lipemia during treatment with pravastatin 20 mg/day. Metabolic parameters of very-low-density lipoprotein (VLDL)-apoB and LDL-apoB were studied using endogenous labeling with stable isotopes. In all patients pravastatin caused an increase in fractional catabolic rates of LDL-apoB without a significant effect on the production rates of apoB-containing lipoproteins. We cannot exclude the possibility that higher doses of statins may decrease VLDL and LDL production.

Safety and efficacy of long-term statin-fibrate combinations in patients with refractory familial combined hyperlipidemia

No monotherapy is able to tackle effectively all atherogenic features of familial combined hyperlipidemia: high low-density lipoprotein (LDL) cholesterol, triglycerides (TG), and plasma fibrinogen, as well as low high-density lipoprotein (HDL) cholesterol. The present study investigated the safety and efficacy of combined pravastotin or simvastatin with gemfibrozil or ciprofibrate treatment on total cholesterol, LDL, TG, plasma fibrinogen, and apoproteins B and A-I in patients with refractory familial combined hyperlipidemia, with or without coronary artery disease. From the initial 420 patients included in the study, 389 (294 men and 95 women, mean age 51 years [range 30 to 65]) completed the study. These patients were followed for a mean period of 29 months (1 year [n = 107], 2 years [n = 102], 3 years [n = 95], and 4 years [n = 85]). Patients given a hypolipidemic diet were randomly assigned to pravastatin + gemfibrozil (n = 135, 20 and 1,200 mg/day, respectively), simvastatin + gemfibrozil (n = 130, 20 and 1,200 mg), or simvastotin + ciprofibrate (n = 124, 20 and 100 mg). Lipid parameters, apoproteins B and A-I, and plasma fibrinogen were assessed every 3 months. Physical and laboratory investigations for adverse effects were performed every month for the first 3 months and every 3 months thereafter. No patient exhibited myopathy or rhabdomyolysis. Five patients (1.3%) were withdrawn from the study because of high transaminases (more than threefold the upper normal limit). Five nonfatal coronary artery disease events were recorded. All 3 combination treatments were more effective in normalizing lipid profile than any monotherapy in the past. Simvastatin + ciprofibrate was more effective than pravastatin + gemfibrozil in reducing LDL, TG, and plasma fibrinogen levels. Simvastatin + gemfibrozil increased HDL levels more than the other 2. The apoprotein B decrease was analogous to the LDL reduction by all combinations, whereas apoprotein A-I was increased more with simvastatin + gemfibrozil. The data suggest that the statin-fibrate combinations used in the study are safe and have a favorable effect on all major coronary artery disease risk factors in patients with refractory familial combined hyperlipidemia with or without coronary artery disease. Early detection of the rare drug-induced reversible hepatotoxicity calls for close monitoring of patients.