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

The Degree of Albuminuria Is Related to Left Ventricular Hypertrophy in Hypertensive Diabetics and Is Associated with Abnormal Left Ventricular Filling: A Pilot Study

The association of albuminuria and left ventricular (LV) hypertrophy (LVH) in diabetics aggra vates the prognosis. The authors studied the relation between LVH and the degree of albu minuria in diabetics and investigated the relationship of albuminuria to LV filling. A comparison was made between 30 hypertensive diabetics, 10 of whom had microalbuminuria (MIC) and 20 had macroalbuminuria (MAC), and 18 diabetics who were normotensive and normalbuminuric (NOR). LV mass index (LVMI) and LV ejection fraction (LVEF) were measured during echocar diography. LV filling pattern at rest and at peak standardized isometric exercise (IME) using handgrip was assessed by measuring E/A (peak velocity of the early/atrial filling waves) of the transmitral flow during Doppler and echocardiography. Each patient underwent a stress ECG test. LVMI was higher in MAC (132.3 ±55.4) than in MIC (115.6 ±32.5) or NOR (90.0 ±31.8) (p<0.01). There were more patients in MAC with LVH (n = 13) and abnormal filling (n = 9 at rest and 16 with IME) than in MIC (LVH = 5, abnormal filling = 1 at rest and 10 during IME) or NOR (LVH = 3, abnormal filling = 1 at rest and 9 during IME) (p < 0.02). LVMI was not related to LVEF. Although blood pressure was not different between MAC and MIC groups, it was signif icantly higher than in the NOR group. This study suggests that a high degree of albuminuria in hypertensive diabetics is associated with greater value for LVMI and an increased incidence of LVH independent of blood pressure level or systolic LV function. LVH is associated with abnormal LV filling. The degree of albuminuria may predict LVMI and LVH, which are associated with abnormal LV filling. This association of abnormal LV filling with albuminuria in hypertensive diabetic patients may account for their high risk of cardiovascular events.

Trimetazidine-induced enhancement of myocardial recovery during reperfusion: a comparative study in diabetic and non-diabetic rat hearts

BACKGROUND

Diabetes mellitus (DM) is a major predisposing factor for ischemic heart disease. Metabolic disturbances in diabetic heart including impaired myocardial glucose uptake and elevated plasma free fatty acids and increased rate of fatty acid beta-oxidation are probably important contributing factors to greater mortality. Trimetazidine (TMZ), a well-studied anti-ischemic agent, has been demonstrated to be beneficial in treatment of coronary artery disease as well as in treatment of diabetic patients. However, studies reporting the effects of the drug against global myocardial ischemia/reperfusion injury, particularly in diabetic hearts, are rare. This study was mainly aimed to investigate the cardioprotective action of TMZ against global ischemia in diabetic hearts and to compare its protective efficiency level with non-diabetics.

METHODS

Twenty streptozotocin-induced diabetic and 20 non-diabetic rats were divided into two groups each. Group I (diabetic, n = 10) and group III (non-diabetic, n = 10) rats were given saline in both pretreatment and acute treatment protocols and reserved as control groups. Group II (diabetic, n = 10) and group IV (non-diabetic, n = 10) rats were both pretreated orally with 3 mg/kg TMZ twice daily for 5 days and treated with TMZ infusion at a concentration of 10(-6) M for 30 min during the experiment. Isolated hearts from each rat were submitted to Langendorff perfusion and a period of 60 min of global ischemia following 60 min of reperfusion. Myocardial post-ischemic recovery was compared in each group using hemodynamic data (peak systolic pressure, end diastolic pressure, +dP/dt(max)), coronary flow, biochemical parameters (CK-MB, cTnT) from coronary effluent, and obtained data were statistically analyzed by both MANOVA and two-sample Hotelling's T2 tests.

RESULTS

Both hemodynamic and biochemical findings signaled a significantly enhanced myocardial recovery provided by TMZ treatment in diabetic and non-diabetic hearts as compared to non-treated hearts. Although efficiency level of TMZ on mechanical recovery was not different between diabetics and non-diabetics, the protective action of TMZ on myocardial damage measured by biochemical parameters was more evident in diabetic hearts than in non-diabetics.

CONCLUSIONS

Shifting myocardial energy metabolism away from fatty acids toward glucose oxidation and regulating transmembrane ion disturbances by TMZ can be considered as an appropriate adjunctive treatment in diabetics, especially in patients undergoing open-heart surgery who will be exposed to global myocardial ischemia.

Comparison of effects of fibrates in patients with hypertriglyceridemia

It has long been known that antihyperlipidemic agents categorized as fibrates are capable of reducing triglyceride concentrations, although the superiority of one over another remains questionable. In the present study, investigators compared treatment results from various fibrates. In all, 60 patients aged 54.1+/-12 y with hypertriglyceridemia were included in the study. Patients who had increased values on liver function tests, had been given a diagnosis of hypothyroidism or chronic renal failure, and who needed statin medication were excluded. Patients were divided into 4 groups according to the medication given; treatments consisted of Lipanthyl 1 x 1, Lipofentrade mark 1 x 1, Lopid 1 x 1, and Lopid 2 x 1. Biochemical and hematologic parameters of patients were recorded at the first visit and at the end of the 2-mo treatment period. A total of 18 patients (30%) were given Lipanthyl 1 x 1, 14 (23.3%) received Lipofen 1 x 1, 16 (26.7%) were treated with Lopid 1 x 1, and 12 (20%) were given Lopid 2 x 1. Effects on triglyceride values were assessed in all groups. Lopid 1 x 1 and Lopid 2 x 1 produced significant decreases in triglyceride values. Most adverse effects were reported in the group given Lopid 2 x 1. In the treatment of hypertriglyceridemia, fibrates have similar effects on tolerability and reliability. However, study findings indicated that Lopid 1 x 1 and 2 x 1 treatments have greater efficacy.

Beyond low-density lipoprotein: addressing the atherogenic lipid triad in type 2 diabetes mellitus and the metabolic syndrome

The metabolic syndrome and type 2 diabetes mellitus are both becoming more prevalent, and both increase the risk of cardiovascular disease. Many patients are not receiving appropriate treatment for the type of dyslipidemia that commonly occurs in these disorders--the so-called 'atherogenic lipid triad' of high serum triglyceride levels, low serum high-density lipoprotein cholesterol (HDL-C) levels, and a preponderance of small, dense, low-density lipoprotein cholesterol (LDL-C) particles. All of the processes involved in atherogenesis can be exacerbated by insulin resistance and/or the metabolic syndrome. Hypertriglyceridemia is a strong predictor of coronary heart disease. There is also an inverse relationship between serum levels of HDL-C and triglycerides in diabetic patients, with low serum HDL-C levels possibly representing an independent risk factor for cardiovascular disease. Small, dense, LDL-C particles are also highly atherogenic as they are more likely to form oxidized LDL and are less readily cleared. Insulin resistance, which is central to the metabolic syndrome and type 2 diabetes mellitus, leads to high levels of very low-density lipoprotein (VLDL), which contain a high concentration of triglycerides, resulting in high serum triglyceride levels and low serum HDL-C levels. Even though modification of the atherogenic lipid triad is probably one of the most effective methods of reducing cardiovascular risk, therapy for diabetic dyslipidemia is often directed to first lowering serum LDL-C levels with a HMG-CoA reductase inhibitor. This may leave substantial excess risk for cardiovascular disease in patients with these types of dyslipidemia. The results of recent trials evaluating HMG-CoA reductase inhibitors have been mixed, with two showing no significant effect on cardiovascular outcomes in subgroups of diabetic patients. The recent CARDS (Collaborative Atorvastatin Diabetes Study) showed that atorvastatin can reduce cardiovascular events in a trial specifically designed for a diabetic population, though the population had to have at least one other risk factor in addition to diabetes mellitus. Fibric acid derivatives, such as fenofibrate, bezafibrate and gemfibrozil, are potentially well suited to the treatment of dyslipidemia that is generally associated with type 2 diabetes mellitus and the metabolic syndrome, as they are usually more effective than HMG-CoA reductase inhibitors for normalizing serum levels of HDL-C and triglycerides. Promising results have been obtained from several trials of fibric acid derivatives including the BIP (Bezafibrate Infarction Prevention) study and the VA-HIT (Veterans Affairs Cooperative Studies Program HDL-C Intervention Trial; gemfibrozil). The FIELD (Fenofibrate Intervention and Event Lowering in Diabetes) trial, a clinical outcomes trial specifically designed to evaluate fenofibrate in a large population of patients with type 2 diabetes mellitus, many of whom have the metabolic syndrome, is underway. The FIELD trial results should shed light on the efficacy and safety of fenofibrate in reducing cardiovascular morbidity in diabetic and metabolic syndrome patients and on the safety profile of combination therapy with fenofibrate and a HMG-CoA reductase inhibitor.

A new perspective in the treatment of dyslipidemia : can fenofibrate offer unique benefits in the treatment of type 2 diabetes mellitus?

Patients with diabetes mellitus are at higher risk for cardiovascular events than those without diabetes. Furthermore, patients with diabetes have a characteristic 'lipid triad' of low high-density lipoprotein-cholesterol (HDL-C) levels, high triglyceride levels, and normal or slightly raised low-density lipoprotein-cholesterol (LDL-C) levels, with a preponderance of small, dense LDL-C particles. Current guidelines on preventing cardiovascular disease recognize the need not only to reduce LDL-C levels, but also to increase HDL-C and decrease triglyceride levels in diabetic patients. Some clinical trials of HMG-CoA reductase inhibitors (statins) have included large populations of diabetic patients. In some of these trials (such as 4S [Scandinavian Simvastatin Survival Study], CARE [Cholesterol and Recurrent Events] trial, and the HPS [Heart Protection Study]), HMG-CoA reductase inhibitor treatment significantly reduced cardiovascular events in diabetic patients, whereas in other trials (ALLHAT-LLT [Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial], ASCOT [Anglo-Scandinavian Cardiac Outcomes Trial]) the reductions were not significant. In CARDS (Collaborative Atorvastatin Diabetes Study), the first large HMG-CoA reductase inhibitor study to enroll only patients with type 2 diabetes, atorvastatin reduced cardiovascular events by 37% (p=0.001) compared with placebo. Fibric acid derivatives (fibrates), which are agonists of peroxisome proliferator-activated alpha receptors, exert their effects by altering the transcription of genes encoding proteins that control lipoprotein metabolism. Fibric acid derivatives are a valuable tool in the treatment of dyslipidemia in patients with diabetes, as they reduce plasma triglyceride levels by 30--50%, increase HDL-C levels by 10--15%, and shift the distribution of LDL subfractions towards larger, less atherogenic particles. The DAIS (Diabetes Atherosclerosis Intervention Study), which was conducted exclusively in patients with type 2 diabetes, found that fenofibrate reduces the progression of angiographic coronary artery disease. The VA-HIT (Veterans Affairs Cooperative Studies Program HDL-C Intervention Trial) showed that gemfibrozil reduced cardiovascular events in subgroups of diabetic patients. A large clinical event study, FIELD (Fenofibrate Intervention and Event Lowering in Diabetes), which is currently being completed, will provide further information on the value of fenofibrate for the reduction of cardiovascular risk in patients with diabetes.

Hyperglycemia, lipoprotein glycation, and vascular disease

Hyperlipidemia and its treatment are currently recognized as important modulators of cardio-vascular mortality in the presence of disordered glucose control. On the other hand, the effects of hyperglycemia and its treatment on hyperlipidemia are not widely appreciated. Hyperglycemia is commonly associated with an increase in intestinal lipoproteins and a reduction in high-density lipoprotein (HDL). This could be a consequence of hyperglycemia-induced glycation of lipoproteins, which reduces the uptake and catabolism of the lipoproteins via the classical low-density lipoprotein (LDL) receptor. A high dietary carbohydrate load increases the glycation of intestinal lipoproteins, prolongs their circulation, and increases their plasma concentration. Hyperglycemia also leads to inhibition of lipoprotein lipase, further aggravating hyperlipidemia. Circulating advanced glycation end-products (AGEs) also bind lipoproteins and delay their clearance, a mechanism that has particularly been implicated in the dyslipidemia of diabetic nephropathy. As uptake via scavenger receptors is not inhibited, glycation increases the proportion of lipoproteins that are taken up via inflammatory cells and decreases the proportion taken up by hepatocytes via classical LDL receptors. This promotes the formation of atheromatous plaques and stimulates inflammation. Hyperglycemia increases the formation of oxidized LDL and glycated LDL, which are important modulators of atherosclerosis and cardiovascular death. The risk of cardiovascular death is increased by even short-term derangement of blood sugar control, owing perhaps to the glycation of lipoproteins and other critical proteins. Glycated LDL could prove very useful in measuring the effect of hyperglycemia on cardiovascular disease, its risk factors, and its complications. Comparing different glucose-lowering and lipid-lowering drugs in respect to their influence on glycated LDL could increase knowledge of the mechanism by which they alter cardiovascular risk.

Effect of antihypertensive treatment on plasma fibrinogen and serum HDL levels in patients with essential hypertension

The influence of hypertension, and its treatment, on circulating lipid and fibrinogen (Fib) concentrations in patients with essential hypertension was investigated. The lipid profile and Fib levels were measured in 353 patients (131 men) with essential hypertension. Their median age was 60 years (range: 18-85 years). All patients had normal results from liver, renal, and thyroid function tests. There were 162 patients (45.9%) who were not receiving antihypertensive treatment. Of the remaining patients, 117 were taking 'lipid-hostile' beta-blockers, thiazide diuretics) antihypertensives and 74 were taking 'lipid-neutral' (angiotensin-converting enzyme inhibitors, calcium channel blockers, angiotensin-II receptor blockers) agents. Patients who were taking 'lipid-hostile' antihypertensive drugs had significantly higher plasma Fib concentrations when compared with those taking 'lipid-neutral' antihypertensives or those not receiving antihypertensive treatment. These differences were not attributable to established factors that influence plasma Fib levels, since when smokers and patients with diabetes mellitus and/or vascular disease were excluded, the difference remained significant. In addition, in these more homogeneous groups, patients receiving 'lipid-neutral' treatment had significantly higher serum high-density lipoprotein (HDL) cholesterol levels when compared with both those taking 'lipid-hostile' antihypertensives and untreated ones. There were no significant differences in the other lipid variables, independently of the presence/absence or the type of antihypertensives. These results suggest that antihypertensive drugs have additional effects, beyond lowering blood pressure, on other vascular risk factors, like Fib and HDL. These effects may depend on the type of drug used.

Matrix metalloproteinases and diabetic vascular complications

Diabetes mellitus (DM) is associated with an increased incidence of cardiovascular events and microvascular complications. These complications contribute to the morbidity and mortality associated with DM. There is increasing evidence supporting a role for matrix metalloproteinases (MMPs) and their inhibitors (tissue inhibitors of matrix metalloproteinases - TIMPs) in the atherosclerotic process. However, the relationship between MMPs/TIMPs and diabetic angiopathy is less well defined. Hyperglycemia directly or indirectly (eg, via oxidative stress or advanced glycation products) increases MMP expression and activity. These changes are associated with histologic alterations in large vessels. On the other hand, low proteolytic activity of MMPs contributes to diabetic nephropathy. Within atherosclerotic plaques an imbalance between MMPs and TIMPs may induce matrix degradation, resulting in an increased risk of plaque rupture. Furthermore, because MMPs enhance blood coagulability, MMPs and TIMPs may play a role in acute thrombotic occlusion of vessels and consequent cardiovascular events. Some drugs can inhibit MMP activity. However, the precise mechanisms involved are still not defined. Further research is required to demonstrate the causative relationship between MMPs/TIMPs and diabetic atherosclerosis. It also remains to be established if the long-term administration of MMP inhibitors can prevent acute cardiovascular events.

Prevention and treatment of the metabolic syndrome

The prevalence of the metabolic syndrome is increasing owing to lifestyle changes leading to obesity. This syndrome is a complex association of several interrelated abnormalities that increase the risk for cardiovascular disease and progression to diabetes mellitus (DM). Insulin resistance is the key factor for the clustering of risk factors characterizing the metabolic syndrome. The National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III defined the criteria for the diagnosis of the metabolic syndrome and established the basic principles for its management. According to these guidelines, treatment involves the improvement of the underlying insulin resistance through lifestyle modification (eg, weight reduction and increased physical activity) and possibly by drugs. The coexistent risk factors (mainly dyslipidemia and hypertension) should also be addressed. Since the main goal of lipid-lowering treatment is to achieve the NCEP low-density lipoprotein cholesterol (LDL-C) target, statins are a good option. However, fibrates (as monotherapy or in combination with statins) are useful for the treatment of the metabolic syndrome that is commonly associated with hypertriglyceridemia and decreased high-density lipoprotein cholesterol (HDL-C) levels. The blood pressure target is < 140/90 mm Hg. The effect on carbohydrate homeostasis should possibly be taken into account in selecting an antihypertensive drug. Patients with the metabolic syndrome commonly have other less well-defined metabolic abnormalities (eg, hyperuricemia and raised C-reactive protein levels) that may also be associated with an increased cardiovascular risk. It seems appropriate to manage these abnormalities. Drugs that beneficially affect carbohydrate metabolism and delay or even prevent the onset of DM (eg, thiazolidinediones or acarbose) could be useful in patients with the metabolic syndrome. Furthermore, among the more speculative benefits of treatment are improved liver function in nonalcoholic fatty liver disease and a reduction in the risk of acute gout.

The ORLIstat and CArdiovascular risk profile in patients with metabolic syndrome and type 2 DIAbetes (ORLICARDIA) Study

BACKGROUND

Metabolic syndrome (MetSyn) is associated with a marked increase in the risk of cardiovascular disease, especially in patients with type 2 diabetes mellitus (DM).

AIM

To investigate the effect of orlistat plus hypocaloric diet (HCD) vs HCD alone on the cardiovascular risk profile in patients with both MetSyn (National Cholesterol Educational Program--NCEP--Adult Treatment Panel III definition) and type 2 DM.

METHODS

This was a prospective, multicentre, open-label, randomized, controlled study. One hundred and twenty-six patients, free of cardiovascular disease at baseline, were included in the final analysis. Ninety-four (73%) patients were treated with orlistat (360 mg/day) and HCD for a 6-month period, while 34 (27%) were on HCD alone. Analysis of covariance was used to assess differences between the treatment groups over time.

MAIN OUTCOME MEASURES

Components of the MetSyn criteria assessed were: waist circumference; systolic and diastolic blood pressure; fasting glucose, triglycerides; high-density lipoprotein cholesterol (HDL-C) plus body mass index; glycosylated haemoglobin (HbA1C); homeostasis model for assessment of insulin resistance (HOMA) index; and total and low-density lipoprotein cholesterol (LDL-C).

RESULTS

By protocol, all patients had MetSyn at baseline. After a 6 month treatment period there were significant differences between the orlistat plus HCD vs the HCD-alone groups in body weight (p = 0.0001), waist circumference (p < 0.0001), fasting glucose (p < 0.0001), HbA(1C) (p < 0.0001), systolic blood pressure (p = 0.024), total cholesterol (p < 0.0001), LDL-C (p = 0.034), and HOMA index (p = 0.022), while there were no significant differences in triglycerides and HDL-C. Orlistat was well tolerated. By the end of the study, 65% of the patients on orlistat plus HCD were still meeting the MetSyn criteria and 41% had four to five MetSyn components vs 91% (p < 0.0001) and 53% (p = 0.017), respectively, of those on HCD alone.

CONCLUSIONS

Orlistat plus HCD favourably modified several cardiovascular risk factors in patients with both MetSyn and type 2 DM. These effects might partly offset the excess cardiovascular risk and improve outcome in this patient population.

The effects of transdermal estradiol alone or with cyclical dydrogesterone on markers of cardiovascular disease risk in postmenopausal women with type 2 diabetes: a pilot study

The objective of this open, longitudinal, controlled study was to assess the effect of transdermal estradiol alone or combined with cyclical dydrogesterone on the markers of cardiovascular disease (CVD) risk in postmenopausal women with type 2 diabetes. The control group consisted of postmenopausal diabetic women who declined menopausal hormone replacement therapy (HRT). Twenty-eight postmenopausal women (19 on HRT and 9 controls) with type 2 diabetes were followed up for 12 months. From the active treatment group 14 women with a uterus in situ had 80 microg/24 hr transdermal estradiol (Fematrix 80; Solvay Healthcare Ltd, Southampton, UK) and oral dydrogesterone 10 mg daily for the first 12 days of the calendar month, whereas 5 women with previous hysterectomy had 80 microg/24 hr transdermal estradiol (Fematrix 80) alone. CVD risk markers were measured before and at regular intervals after starting HRT. The main outcome measures were weight, systolic and diastolic blood pressure, fasting plasma glucose, glycated hemoglobin (HbA1c), glucose/insulin ratio, total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, lipoprotein (a), high-sensitivity C-reactive protein (hs-CRP), fibrinogen, and endothelin-1. Transdermal estradiol with or without dydrogesterone in women with type 2 diabetes did not adversely affect any of the measured markers of cardiovascular risk. There was a significant decrease in HbA1c, total cholesterol, and LDL cholesterol at 6 months in women receiving HRT. Some of the cardiovascular disease risk markers may improve in postmenopausal women with type 2 diabetes with transdermal estradiol. This effect may have important clinical implications and it deserves further investigation in appropriately designed trials.

Early vascular benefits of statin therapy

Large-scale trials established that statin administration in hypercholesterolaemic individuals and patients with coronary heart disease (CHD) significantly reduces the risk of vascular events and death. This benefit was primarily attributed to their actions on lipids. This review focuses on the benefits (clinical and experimental) of statins observed soon (approximately 12 weeks) after their administration. Statins rapidly increase nitric oxide production and improve endothelial function (e.g. increased flow-mediated dilatation). Similarly, antioxidant properties decrease the susceptibility of low density lipoprotein cholesterol to oxidation. Statins inhibit the migration of macrophages and smooth muscle cell proliferation leading to an antiproliferative effect and the stabilisation of atherosclerotic plaques. Anti-inflammatory effects include a reduction in serum C-reactive protein levels, inflammatory and proinflammatory cytokines (e.g. IL-6, IL-8), adhesion molecules (e.g. ICAM-1, VCAM-1) and other acute phase proteins. Statins influence the haemostatic system. They reduce tissue factor expression and platelet activity, whereas fibrinolysis can be enhanced. Statins improve microalbuminuria, renal function, hypertension and arterial wall stiffness. A significant reduction of the carotid intima media thickness (IMT) was also reported early after statin treatment. These early effects of statins probably contribute to the significant reduction in vascular events seen in some 'short-term' studies. There is a need to further elucidate the rapid and non-lipid lowering properties of statins.

Apolipoprotein E polymorphism and atherosclerosis

The relationship between apolipoprotein (apo) E and vascular disease has been the subject of a considerable amount of research. However, this relationship is far from clearly defined. This deficiency appears to be due to a multitude of factors. Among these are differences in ethnicity, age (and possibly gender), diagnostic criteria, and environmental factors (eg, diet and smoking) that have contributed to the contradictory findings. Several diseases and their treatment may also influence this relationship. There are also documented interactions between apo E genotypes and other genes or vascular risk factors. One possible clinically relevant application of identifying the apo E genotype could be to assess the response to a particular drug treatment. It may also be that apo E polymorphism will become a good predictor of vascular death (eg, from myocardial infarction or stroke) rather than an indicator of the risk of developing vascular disease but without an acute ischemic event. More research is required to define the place of apo E genotyping in the management of vascular disease in its various forms. Whatever the future brings, the evaluation of apo E genotypes will need to be rapid, cheap, and technically undemanding before this investigation becomes widely available and clinically relevant.

Statins and renal function

Renal disease is often associated with an increased risk of vascular events. Moreover, an accelerated form of atherosclerosis commonly occurs in these patients. The reasons for these associations are not clearly defined but include the widespread presence of several established risk factors (eg, dyslipidemia, hypertension, and diabetes). Other predictors of atherosclerotic disease may also be abnormally elevated (eg, homocysteine, fibrinogen, and lipoprotein a). In addition, there is evidence that impaired renal function per se predicts vascular risk. Despite this high-risk background, the potential benefit of treatment with statins has not been widely investigated in these patients. The present review considers the evidence (experimental and clinical) that statins exert beneficial effects in patients with different types of renal disease. This includes improved renal function, decreased microalbuminuria, and a fall in blood pressure. Statins may also improve renal allograft survival. The potential mechanisms mediating these effects are considered. The interactions between statins and several risk factors that may be present in patients with impaired renal function are also considered. There is an urgent need to define the role of statins in these high-risk patients. Which is the statin of choice? This question is relevant because impaired renal function can interfere with statin pharmacokinetics. Furthermore, other drugs administered to these patients may cause serious interactions with statins.

Are high-density lipoprotein and triglyceride levels important in secondary prevention: impressions from the BIP and VA-HIT trials

Two major trials, the Bezafibrate Infarction Prevention Trial (BIP) and the Veterans Affairs High-Density Lipoprotein Cholesterol Intervention Trial (VA-HIT) were conducted to clarify the contribution of correcting diminished high density lipoprotein (HDL) (and lowering triglyceride, TG) levels to the risk of cardiovascular events in patients with coronary heart disease (CHD). In BIP, bezafibrate did not significantly reduce the risk of CHD. In contrast, in VA-HIT, gemfibrozil significantly reduced the risk of CHD (22% reduction in primary end point, P=0.006). These trials differ in several respects making direct comparisons difficult. For example, the placebo arm in VA-HIT had a greater prevalence of primary events than that in BIP (22 vs. 15%). The baseline mean LDL value in BIP was also higher compared to that in VA-HIT (148 vs. 112 mg/dl; 3.82 vs. 2.89 mmol/l). Other trials (e.g., AFCAPS and LIPID) showed that patients with LDL values similar to those in BIP benefited significantly from treatment with statins. Therefore, the BIP population may have been more effectively treated with a statin. In contrast, in VA-HIT the LDL level was close to those recommended in the USA and the UK for secondary prevention (100 and 115 mg/dl; 2.6 and 3.0 mmol/l, respectively). Guidelines emphasise that the LDL level is the main treatment target. However, BIP and VA-HIT suggest that correcting HDL and TG levels may be beneficial especially when the LDL level has reached the target value. We may have become too focused on LDL levels and the use of statins.

The role of platelets in peripheral arterial disease: therapeutic implications

Peripheral arterial disease (PAD) is associated with platelet hyperaggregability as well as an increase in morbidity and mortality from myocardial infarction and stroke. Enhanced platelet activation in PAD may substantially contribute to these adverse outcomes. A relative resistance to aspirin therapy has been reported in patients with PAD. Therefore, clopidogrel may be superior to aspirin in treatment of PAD. Furthermore, the aspirin + clopidogrel combination could be more effective than monotherapy but its risk-benefit ratio has yet to be evaluated. Clopidogrel is preferable to ticlopidine because of its safer profile and the convenience of once-daily administration. The glycoprotein (Gp) IIb/IIIa inhibitors may also find a place as short-term therapy after peripheral angioplasty. There is a need to consider the use of clopidogrel in patients who cannot tolerate aspirin. Patients who have an event while taking aspirin also present a problem. One possibility here is to substitute aspirin with clopidogrel or to add clopidogrel to the aspirin. Although these options are currently not evidence based in patients with PAD, there is emerging evidence showing that they are realistic choices.

Beyond LDL-C--the importance of raising HDL-C

Epidemiological studies have established that low levels of high-density lipoprotein cholesterol (HDL-C) are associated with an increased risk of coronary heart disease (CHD). Recent studies have demonstrated that low HDL-C levels, and high triglycerides and total cholesterol levels are independent predictors of CHD, and that the combination of these lipid abnormalities increases the risk of coronary events. In lipid-modifying intervention studies, agents that raise HDL-C levels have been shown to reduce the incidence of major coronary events. The VA-HIT study consisted of patients with low-density lipoprotein cholesterol (LDL-C) levels similar to those recommended by several guidelines but with low levels of HDL-C. This trial demonstrated that raising HDL-C levels with gemfibrozil reduced the risk of CHD-related events. While the mechanisms by which HDL-C exerts its anti-atherogenic effects have yet to be fully elucidated, its role in the reverse transport of cholesterol and the beneficial effects on endothelial function are plausible explanations for these actions. Although LDL-C reduction is the primary goal in the treatment of dyslipidaemia, current guidelines recognise low HDL-C levels as a major risk factor for CHD. Indeed, the NCEP ATP III guidelines suggest that the treatment of isolated low HDL-C levels in CHD patients or individuals with CHD risk equivalents should be considered. The differing abilities of statins to raise HDL-C levels may be an important factor when making treatment decisions. New lipid-modifying drugs with beneficial effects on both HDL-C and LDL-C levels would be desirable additions to the currently available therapeutic options.

The choice of antihypertensive drugs in patients with erectile dysfunction

It is well established that hypertension and the more traditional anti-hypertensive drugs are associated with erectile dysfunction (ED). There is evidence showing that two antihypertensive drugs--doxazosin and losartan--have a positive effect on erectile function. Therefore these drugs may decrease the incidence of ED in patients who need treatment for hypertension. Doxazosin and/or losartan can also be beneficial in patients who develop ED after starting treatment with other antihypertensive drugs. These options could, in turn, ensure better compliance and blood pressure control. A fall in the overall cost of treatment will also be anticipated if there is a reduced need for drugs prescribed for ED in patients with hypertension.

Differences in lipid profiles of patients given rosiglitazone followed by pioglitazone

To compare the effects of rosiglitazone and pioglitazone on patient lipid levels in a clinical practice setting, we retrospectively examined charts of 20 patients in our practice. The patients had been treated for type 2 diabetes for 3 or more months with rosiglitazone (4 mg b.i.d.) followed immediately by 3 or more months' treatment with pioglitazone (45 mg once daily). Glycaemic control was excellent and essentially equivalent during the two treatments. At baseline, the mean HbA1c level was 7.6%; it dropped to 6.6% and 6.3% with rosiglitazone and pioglitazone treatment, respectively. Lipid levels, however, differed with the two treatments. Triglyceride levels rose 13% with rosiglitazone treatment, but fell 14% below baseline levels with pioglitazone therapy--a 24% reduction overall (p = 0.02). Rosiglitazone was associated with a significant increase in low-density lipoprotein cholesterol (LDL-C) levels (35%, p < 0.001 vs. baseline) and a significant increase in total cholesterol levels (22%, p < 0.001 vs. baseline). When pioglitazone replaced rosiglitazone therapy, LDL-C fell 25% (p < 0.001), and total cholesterol fell 19% (p < 0.001 between treatments). HDL-C levels did not change significantly during either treatment. Both drugs were otherwise safe and well tolerated. One patient receiving rosiglitazone and one receiving pioglitazone developed oedema that resolved without therapy discontinuation. Liver enzyme levels and blood pressure were unaffected in this group of patients. Because patients with diabetes are at risk for coronary artery disease, physicians should consider each agent's effects on lipid levels when choosing a specific thiazolidinedione.

Management of ischaemic heart disease in diabetic patients--is there a role for cardiac metabolic agents?

Diabetes mellitus (DM) increases the risk of cardiovascular events in patients with cardiovascular disease as well as in patients without any previous history of ischaemic heart disease (IHD). The management of IHD in diabetic patients remains a difficult challenge. However, some of these treatments are not as effective or well-tolerated in diabetic patients as in non-diabetic patients. An important effect of diabetes, that in turn influences cardiac function, is the switch from carbohydrate oxidation to free fatty acid and ketone oxidation. The correction of the alterations to cardiac metabolism associated with DM may represent a new approach to the management of IHD in these patients. Results obtained in anginal patients with the metabolic agent trimetazidine and in infarcted patients with glucose-insulin-potassium (GIK) are consistent with this hypothesis.