Management of lipid disorders in the elderly

Implications of statin adverse effects in the elderly

The elderly differ from younger people in the relation of cholesterol to heart disease and mortality. Clinical trial evidence supports epidemiological findings in showing that high cholesterol weakens in its relationship to heart disease with age and loses (and in older age reverses) its relation to mortality. Randomised trial data confirm that lowering cholesterol no longer extends life in the elderly, even those at high risk of heart disease, and no evidence supports the presumption that the impact on all-cause morbidity is any more favourable. These findings increase the importance of statin adverse effects (AEs) in this group. Furthermore, the elderly may be more vulnerable to known AEs, and evidence provides cause for concern that new risks may supervene, including cancer, neurodegenerative disease and heart failure. Physiological evidence regarding the impact of statins on mitochondrial function, and mitochondrial function on ageing, support these concerns. Additionally, the impact of statin AEs (e.g., muscle and cognitive problems) may be amplified in this group. Effects may be misattributed to ageing. Even modestly lower cognitive and physical function in older elderly prognosticates increased disability, hospitalisation, institutionalisation, and mortality. Disability, once present, is less likely to recover. Because the risk for AEs is unattended by evidence of net benefit to the person, the use of statins in the elderly should be undertaken, if at all, with circumspection and close scrutiny for adverse effects.

Should the Insulin Resistance Syndrome be Treated in the Elderly?

The insulin resistance syndrome represents the co-occurrence of hyperglycaemia, hypertension, central and overall obesity, and dyslipidaemia characterised by low high density lipoprotein-cholesterol (HDL-C) and high triglyceride levels. Epidemiologic studies have revealed an increasing prevalence of the insulin resistance syndrome in elderly populations. Indeed, recent data indicate that over 40% of US adults aged > or =60 years meet current criteria for the insulin resistance syndrome. Patients with this syndrome are at increased risk for the development of both cardiovascular disease (CVD) and type 2 diabetes mellitus, two of the most significant health problems among people >65 years of age. Identification and treatment of the insulin resistance syndrome may thus represent an important approach to reducing the overall burden of morbidity and mortality in the elderly. While development of the insulin resistance syndrome is partly determined by modifiable environmental factors, there may be a genetic basis for the syndrome, with high levels of concordance among monozygotic twins. Ongoing research focusing on the pathophysiology of this syndrome has implicated insulin resistance as the central disorder underlying both the development of diabetes as well as the pro-thrombotic endothelial dysfunction characteristic of CVD. Studies aimed at reversing insulin resistance have identified weight loss, exercise and pharmacological treatment with metformin, thiazolidinediones, HMG-CoA reductase inhibitors (statins) and ACE inhibitors as potential therapies to prevent the development of type 2 diabetes. However, although insulin sensitisation may be beneficial for preventing type 2 diabetes, there are no data yet available to show whether this strategy will reduce the incidence of CVD. Increased exercise and other healthy lifestyle changes form the cornerstone of therapy for elderly patients with the insulin resistance syndrome. In addition, active identification and aggressive management of traditional cardiovascular risk factors are the current standard of care. For elderly patients, recent studies have conclusively demonstrated the safety and efficacy of pharmacological management of elevated blood pressure and cholesterol levels.

Update on cardiovascular disease in post-menopausal women

Cardiovascular disease (CVD), and in particular coronary artery heart disease (CAHD), is the leading cause of morbidity and mortality in women. Until recently, most of our knowledge about the pathophysiology of CVD in women - and, subsequently, management guidelines - were based on studies conducted mostly in men. While similar mechanisms operate to induce CVD in women and men, gender-related differences exist in the anatomy and physiology of the myocardium, and sex hormones modify the course of disease in women. Women, more than men, have their initial manifestation of CAHD as angina pectoris; are likely to be referred for diagnostic tests at a more advanced stage of disease, and are less likely than men to have corrective invasive procedures. The overall morbidity and mortality following the initial ischaemic heart event is worse in women, and the case fatality rate is greater in women than in men. Also, the relative impact of impaired vasoreactivity of the coronary artery, increased viscosity of the blood and dysregulation of automaticity and arrhythmia, is greater in women than in men. The most effective means of decreasing the impact of CVD on women's health is by an active approach from childhood to proper principles of healthcare in order to modify the contribution of specific risk factors. The latter include obesity, abnormal plasma lipid profile, hypertension, diabetes mellitus, cigarette smoking, sedentary lifestyle, increased blood viscosity, augmented platelet aggregability, stress and autonomic imbalance. The use of lipid-lowering drugs has not been adequately studied in women but reports from studies conducted mostly in men do predict an advantage also to women. Oestrogen deficiency after spontaneous or medically induced menopause is an important risk factor for CVD and CAHD. Observational and mechanistic data suggest a role for oestrogen replacement after menopause for primary, and possibly secondary, prevention of CVD. However, two recent prospective trials suggest that treatment de novo with hormone replacement of older post-menopausal women after an acute coronary event may not confer cardiovascular protection and may increase the risk of thromboembolic disease. Results of ongoing long-term studies may determine the beneficial role of hormone replacement versus potential risks involved with this treatment.

How well tolerated are lipid-lowering drugs?

It has been clearly established that lipid-lowering treatments [such as 3-hydroxyl-3-methylglutamyl coenzyme A reductase inhibitors ('statins') or fibrates] can reduce cardiovascular events, and with one of the statins even total mortality, in high-risk populations. Intervention studies have not included the very old, but it is generally assumed that this patient group would benefit from these treatments to an extent similar to younger patients. Worries about the associations seen in observational studies between low cholesterol levels and cancer, cerebral haemorrhage or mood and behaviour change have been largely overcome by findings from the latest large drug intervention trials, which do not show any increase in these conditions with statin or fibrate treatments. The common adverse effects associated with these drugs are relatively mild and often transient in nature. Potentially more serious adverse effects, which are more clearly related to drug treatment and are probably dose-dependent, include elevations in hepatic transaminase levels and myopathy; however, these effects are uncommon and generally resolve rapidly when treatment is stopped. The risk of myopathy with fibrate treatment is increased in patients with renal impairment, and the risk of myopathy with statin treatment increases with co-administration of drugs that inhibit statin metabolism or transport. Other adverse effects are related to specific drugs, for example, clofibrate is associated with an increased risk of gallstones. Studies in elderly patients have not shown an increased risk of adverse effects with lipid-lowering drugs compared with younger patients, but in clinical practice there may be some increased risk, particularly with regards to drug interactions. Therefore, lipid-lowering drugs should be administered with extra caution to elderly patients.