Safety of drug therapies used for weight loss and treatment of obesity

Some of the medications used for weight loss in the management of obesity have been associated with unacceptable morbidity and mortality. Safety concerns have led to the withdrawal of aminorex, followed by the fenfluramines in 1997, and phenylpropanolamine (norephedrine) in 2000. Aminorex was associated with an increased prevalence of primary pulmonary hypertension (PPH), fenfluramines with an increased prevalence of PPH and valvulopathy, and phenylpropanolamine with an increased risk of haemorrhagic stroke. Several studies have investigated the safety of the fenfluramines, yet the benefit-risk profile has not been conclusively quantified. This is due to several deficiencies in the published studies, including a lack of data on the baseline prevalences of comorbid conditions in obese subjects, and potential confounders and biases in the study designs. Although several studies and systematic reviews support an increased risk of PPH and valvulopathy in patients who have taken fenfluramines, without knowledge of the background prevalence it is not possible to determine if the exposure preceded the outcome. The population at higher risk of these adverse effects includes those taking higher doses or with a longer duration of exposure to fenfluramines and those with pre-existing cardiac disease or a genetic predisposition. Patients exposed to fenfluramines continue to be monitored, with some follow-up studies indicating no overall worsening in valvulopathy over time. There are limited efficacy and safety data for amfepramone (diethylpropion) and phentermine and their approval for the management of obesity is limited to short-term use. Orlistat and sibutramine are the only currently approved medications for long-term management of obesity. Although the benefit-risk profiles of sibutramine and orlistat appear positive, sibutramine continues to be monitored because of long-term safety concerns. The safety and efficacy of currently approved drug therapies have not been evaluated in children and elderly patient populations and there is limited information in adolescents, whilst the long-term safety of current and potential new drug therapies in adults will require several years of postmarketing surveillance to fully elucidate their adverse effect profiles.

Cost-effectiveness of cholesterol-lowering therapy with pravastatin in patients with previous acute coronary syndromes aged 65 to 74 years compared with younger patients: results from the LIPID study

BACKGROUND

We compared cost-effectiveness of pravastatin in a placebo-controlled trial in 5500 younger (31-64 years) and 3514 older patients (65-74 years) with previous acute coronary syndromes.

METHODS

Hospitalizations and long-term medication within the 6 years of the trial were estimated in all patients . Drug dosage, nursing home, and ambulatory care costs were estimated from substudies. Incremental costs per life saved of pravastatin relative to placebo were estimated from treatment effects and resource use.

RESULTS

Over 6 years, pravastatin reduced all-cause mortality by 4.3% in the older patients and by 2.3% in the younger patients. Older patients assigned pravastatin had marginally lower cost of pravastatin and other medication over 6 years (A dollar 4442 vs A dollar 4637), but greater cost offsets (A dollar 2061 vs A dollar 897) from lower rates of hospitalizations. The incremental cost per life saved with pravastatin was A dollar 55500 in the old and A dollar 167200 in the young. Assuming no treatment effect beyond the study period, the life expectancy to age 82 years of additional survivors was 9.1 years in the older and 17.3 years in the younger. Estimated additional life-years saved from pravastatin therapy were 0.39 years for older and 0.40 years for younger patients. Incremental costs per life-year saved were A dollar 7581 in the older and A dollar 14944 in the younger, if discounted at 5% per annum.

CONCLUSIONS

Pravastatin therapy was more cost-effective among older than younger patients, because of their higher baseline risk and greater cost offsets, despite their shorter life expectancy.

Apo B versus cholesterol in estimating cardiovascular risk and in guiding therapy: report of the thirty-person/ten-country panel

There is abundant evidence that the risk of atherosclerotic vascular disease is directly related to plasma cholesterol levels. Accordingly, all of the national and transnational screening and therapeutic guidelines are based on total or LDL cholesterol. This presumes that cholesterol is the most important lipoprotein-related proatherogenic risk variable. On the contrary, risk appears to be more directly related to the number of circulating atherogenic particles that contact and enter the arterial wall than to the measured concentration of cholesterol in these lipoprotein fractions. Each of the atherogenic lipoprotein particles contains a single molecule of apolipoprotein (apo) B and therefore the concentration of apo B provides a direct measure of the number of circulating atherogenic lipoproteins. Evidence from fundamental, epidemiological and clinical trial studies indicates that apo B is superior to any of the cholesterol indices to recognize those at increased risk of vascular disease and to judge the adequacy of lipid-lowering therapy. On the basis of this evidence, we believe that apo B should be included in all guidelines as an indicator of cardiovascular risk. In addition, the present target adopted by the Canadian guideline groups of an apo B <90 mg dL(-1) in high-risk patients should be reassessed in the light of the new clinical trial results and a new ultra-low target of <80 mg dL(-1) be considered. The evidence also indicates that the apo B/apo A-I ratio is superior to any of the conventional cholesterol ratios in patients without symptomatic vascular disease or diabetes to evaluate the lipoprotein-related risk of vascular disease.

Systematic review: Hormone therapy and cardiovascular disease: a systematic review and meta-analysis

BACKGROUND

Despite decades of evidence from observational studies, the use of hormone therapy for the prevention of cardiovascular disease (CVD) among postmenopausal women is controversial. The recent completion of several randomised clinical trials examining the effects of hormone therapy on CVD presents an opportunity to provide a more precise estimate of the cardiovascular risks of hormone therapy.

OBJECTIVE

To summarise the effects of hormone therapy on CVD in postmenopausal women.

SEARCH STRATEGY

MEDLINE, EMBASE, the Cochrane Library, DARE and CENTRAL were searched for clinical trials reporting mortality and/or CVD outcomes in association with hormone therapy. Bibliographies and editorials were also reviewed. All studies were reviewed and rated for quality independently by two reviewers.

SELECTION CRITERIA

High quality, randomised placebo-controlled clinical trials of hormone therapy (duration greater than one year) in non-hospitalised postmenopausal women were included.

DATA COLLECTION AND ANALYSIS

Summary relative risks were estimated for all-cause mortality, coronary heart disease (CHD) mortality, non-fatal acute myocardial infarction (AMI) and all stroke.

MAIN RESULTS

Seven randomised clinical trials met the inclusion criteria. The use of hormone therapy had no significant effect on all-cause mortality, non-fatal AMI or CHD mortality, with relative risks of 1.02 [95% confidence interval (CI) 0.93-1.13], 1.00 (0.88-1.14) and 0.99 (0.82-1.21), respectively. For all stroke, the summary relative risk was 1.29 (1.13-1.48).

AUTHOR'S CONCLUSIONS

This systematic review, incorporating the latest available trial data, shows that hormone therapy does not significantly change the risk of all-cause morality, CHD death or non-fatal AMI but increases the risk of stroke in postmenopausal women.

Early and late benefits of high-dose atorvastatin in patients with acute coronary syndromes: results from the PROVE IT-TIMI 22 trial

OBJECTIVES

Our objective was to determine the timing of benefit with intensive statin therapy after an acute coronary syndrome (ACS) in two time windows: an early window soon after an ACS and a late window in more stable patients.

BACKGROUND

The Pravastatin or Atorvastatin Evaluation and Infection Therapy-Thrombolysis In Myocardial Infarction 22 (PROVE IT-TIMI 22) trial showed that the use of intensive statin therapy improved clinical outcomes over two years in ACS patients versus standard therapy. The relative contributions of early or late effects to the overall clinical efficacy of intensive therapy are presently unclear.

METHODS

A total of 4,162 patients with ACS were recruited in the PROVE IT-TIMI 22 trial. Patients were randomized to intensive statin therapy (atorvastatin, 80 mg) or standard therapy (pravastatin, 40 mg). The composite triple end point of death, MI, or rehospitalization for recurrent ACS was determined in each group at 30 days. The composite triple and primary end points were assessed in stable patients from six months to the end of study, after censoring for clinical events before six months.

RESULTS

The composite end point at 30 days occurred in 3.0% of patients receiving atorvastatin 80 mg versus 4.2% of patients receiving pravastatin 40 mg (hazard ratio [HR] = 0.72; 95% confidence interval [CI], 0.52 to 0.99; p = 0.046). In stable patients, atorvastatin 80 mg was associated with a composite event rate of 9.6% versus 13.1% in the pravastatin 40 mg group (HR = 0.72; 95% CI, 0.58 to 0.89; p = 0.003).

CONCLUSIONS

Intensive statin therapy early after ACS leads to a reduction in clinical events at 30 days, consistent with greater early pleiotropic effects. In stable patients, intensive statin therapy provides long-term reduction in clinical events when compared with standard therapy. Thus, ACS patients should be started in-hospital and continued long-term on intensive statin therapy.

Relation of diet to cardiovascular disease risk factors in subjects with cardiovascular disease in Australia and New Zealand: analysis of the Long-Term Intervention with Pravastatin in Ischaemic Disease trial

BACKGROUND

Comparisons of the relation of diet with coronary heart disease (CHD) between countries with similar socioeconomic environments have been few. Patients in Australia and New Zealand (n = 9014) who participated in a large secondary prevention trial had significantly different CHD mortality rates.

OBJECTIVE

The objective of this study was to ascertain the effects of nutrient consumption on cardiovascular disease risk in patients from the 2 countries.

DESIGN

Nutrient consumption patterns were surveyed in a subgroup of 1077 patients on 3 occasions over 4 y during an intervention trial with a statin.

RESULTS

Within the entire cohort of 9014 patients, the New Zealanders had significantly (40%) more cardiovascular deaths than did the Australians. In the subgroup of 1077 patients, the New Zealanders were found at entry to have eaten significantly more total (69.34 +/- 12.35 compared with 66.45 +/- 12.9 g/d) and saturated (26.23 +/- 8.41 compared with 24.37 +/- 7.36 g/d) fat (P < 0.001 for each) and to have significantly (4%) higher concentrations of LDL cholesterol (3.96 +/- 0.74 compared with 3.8 +/- 0.76 mmol/L; P < 0.001) than did the Australians. At baseline, patients with previous coronary artery bypass grafting had diets that were significantly different from those of patients without previous coronary artery bypass grafting. Relations between nutrients and plasma lipids confirmed the direct effects of saturated fatty acids on LDL cholesterol and of alcohol on plasma triacylglycerol and HDL cholesterol. Dietary counseling throughout the trial led to significant improvements in compliance with guidelines. However, neither the baseline nor the improved 1-y nutrient intakes predicted future changes in cardiovascular events.

CONCLUSION

Differences in CHD mortality and in LDL-cholesterol concentrations between 2 populations with similar socioeconomic and cultural backgrounds were consistent with the amounts and types of fats eaten.

Failure of current public educational campaigns to impact on the initial response of patients with possible heart attack

AIMS

The National Heart Foundation of Australia recognizes that the risk of lethal arrhythmias is greater very early after the onset of myocardial infarction and that the more promptly flow can be restored in the infarct-related artery the greater will be the benefits for survival and preservation of heart function. The Heart Foundation has therefore conducted several public media campaigns to encourage patients to seek help more promptly and evaluated their impact.

METHODS

Since 1996, we have conducted four surveys of delays preceding admission of patients to coronary care units throughout Australia to assess the impact of the Heart Foundation's media campaigns. Data were collected on 1665 patients who presented to 73 hospitals; information on patient delay was available for 1178 of them.

RESULTS

There were no significant differences in patient delay (median 1.5-2.0 h) in the four surveys from 1996 to 2002, nor when patients were categorized by age, sex, presenting diagnosis or history of previous myocardial infarction or coronary revascularization by percutaneous or surgical techniques.

CONCLUSION

New approaches are needed to reduce patient-related delay after the onset of symptoms suggesting possible myocardial infarction.

White Blood Cell Count Predicts Reduction in Coronary Heart Disease Mortality With Pravastatin

Background— Elevated serum inflammatory marker levels are associated with a greater long-term risk of cardiovascular events. Because 3-hydroxy-3-methylglutaryl coenzyme-A reductase inhibitors (statins) may have an antiinflammatory action, it has been suggested that patients with elevated inflammatory marker levels may have a greater reduction in cardiovascular risk with statin treatment.

Methods and Results— We evaluated the association between the white blood cell count (WBC) and coronary heart disease mortality during a mean follow-up of 6.0 years in the Long-Term Intervention With Pravastatin in Ischemic Disease (LIPID) Study, a clinical trial comparing pravastatin (40 mg/d) with a placebo in 9014 stable patients with previous myocardial infarction or unstable angina. An increase in baseline WBC was associated with greater coronary heart disease mortality in patients randomized to placebo (hazard ratio for 1×10 9 /L increase in WBC, 1.18; 95% CI, 1.12 to 1.25; P <0.001) but not pravastatin (hazard ratio, 1.02; 95% CI, 0.96 to 1.09; P =0.56; P for interaction=0.004). The numbers of coronary heart disease deaths prevented per 1000 patients treated with pravastatin were 0, 9, 30, and 38 for baseline WBC quartiles of <5.9, 6.0 to 6.9, 7.0 to 8.1, and >8.2×10 9 /L, respectively. WBC was a stronger predictor of this treatment benefit than the ratio of total to high-density lipoprotein cholesterol and a global measure of cardiac risk. There was also a greater reduction ( P =0.052) in the combined incidence of cardiovascular mortality, nonfatal myocardial infarction, and stroke with pravastatin as baseline WBC increased (by quartile: 3, 41, 61, and 60 events prevented per 1000 patients treated, respectively).

Conclusions— These data support the hypothesis that individuals with evidence of inflammation may obtain a greater benefit from statin therapy.

COX‐2 inhibitors: exemplars of the drug‐safety conundrum

Using clinical trials to assess long-term drug safety is problematic; in Australia, simple data linkage based on Medicare numbers may provide useful monitoring information.

Albuminuria is evident in the early stages of diabetes onset: results from the Australian Diabetes, Obesity, and Lifestyle Study (AusDiab)

BACKGROUND

Albuminuria is a common complication of diabetes and a leading cause of end-stage renal disease. We determined the prevalence of and factors associated with albuminuria in an Australian population and examined the association of albuminuria with glucose tolerance.

METHODS

The Australian Diabetes, Obesity, and Lifestyle Study included 11,247 adults aged 25 years and older from 42 randomly selected areas of Australia. Microalbuminuria is defined as an albumin-creatinine ratio of 22 to 220 mg/g (2.5 to 25 mg/mmol) in men and 31 to 220 mg/g (3.5 to 25 mg/mmol) in women, and macroalbuminuria is defined as an albumin-creatinine ratio of 220 mg/g or greater (> or =25.0 mg/mmol).

RESULTS

Overall, 25.3% of patients with diabetes mellitus (known [KDM] and newly diagnosed [NDM], type 1 and type 2) had evidence of albuminuria (21.0%, microalbuminuria; 4.3%, macroalbuminuria). Prevalence increased with increasing glycemia (normal glucose tolerance [NGT], 5.1%; impaired fasting glucose [IFG], 9.3%; impaired glucose tolerance, 11.0%; NDM, 17.8%; and KDM, 32.6% [type 2 only]). Patients with diabetes (KDM and NDM) and IFG had an increased risk for albuminuria compared with those with NGT independent of age, sex, and other known risk factors for albuminuria. Logistic regression modeling identified age, duration of diabetes, systolic blood pressure, current smoking, body mass index, and glycated hemoglobin level as independent risk factors for albuminuria.

CONCLUSION

This Australian population-based study shows that albuminuria is common among patients with established diabetes, is present before the onset of diabetes, and becomes more prevalent with worsening glucose tolerance.

Statins for Stroke Prevention

The occurrence of stroke increases with age, particularly affecting the older elderly, a population also at higher risk for coronary heart disease (CHD). Epidemiological and observational studies have not shown a clear association between cholesterol levels and all causes of stroke. Nonetheless, large, long-term statin trials in patients with established CHD or at high risk for CHD have shown that statins decrease stroke incidence in these populations. Combined data from 9 trials including 70 070 patients indicated relative and absolute risk reductions for stroke of 21% and 0.9%, respectively, with statins. The number of strokes prevented per 1000 patients treated for 5 years in patients with CHD is 9 for statins, compared with 17.3 for antiplatelet agents. Statins have not yet been shown to reduce stroke risk in the typical general population without known CHD, nor have they been shown to prevent recurrent stroke in patients with prior stroke. Potential reasons for the effects of statins on stroke and the non–cholesterol-lowering mechanisms that may be involved are discussed. Treatment strategies based on global cardiovascular risk may be most effective. Additional studies in patients representative of the typical stroke population are needed.

Depression and cardiovascular morbidity and mortality: cause or consequence?

BACKGROUND

Depression after myocardial infarction has been associated with increased cardiovascular mortality. This study assessed whether depressive symptoms were associated with adverse outcomes in people with a history of an acute coronary syndrome, and evaluated possible explanations for such an association.

METHODS AND RESULTS

Depressive symptoms were assessed using the General Health Questionnaire at least 5 months after hospital admission for acute myocardial infarction or unstable angina in 1130 participants of the Long-Term Intervention with Pravastatin in Ischaemic Disease (LIPID) Study, a multicentre, placebo-controlled, clinical trial of cholesterol-lowering treatment. Cardiovascular symptoms, self-rated general health, cardiovascular risk factors, employment status, social support and life events were also assessed at the baseline visit. Cardiovascular death (n=114), non-fatal myocardial infarction (n=108), non-fatal stroke (n=53) and unstable angina (n=274) were documented during a median follow-up period of 8.1 years. Individuals with depressive symptoms (General Health Questionnaire score >/=5; 22% of participants) were more likely to report angina, dyspnoea, claudication, poorer general health, not being in paid employment, few social contacts and/or adverse life events (P<0.05 for all). There was a modest association between depressive symptoms and cardiovascular events (hazard ratio [HR] 1.42, 95% confidence interval [CI] 1.13-1.77), but not cardiovascular death (HR 1.12. 95% CI 0.71-1.77). After adjustment for symptoms related to cardiovascular disease, the HR for cardiovascular events was 1.22 (95% CI 0.97-1.53). After further adjustment for employment status, social support and life events, the HR was 1.13 (95% confidence interval 0.87-1.47).

CONCLUSIONS

There was no significant association between depressive symptoms and fatal or non-fatal cardiovascular events after adjustment for cardiovascular symptoms associated with poorer prognosis. Previously observed associations between depression and cardiovascular mortality may not be causal.

"Stress" and coronary heart disease: psychosocial risk factors

An Expert Working Group of the National Heart Foundation of Australia undertook a review of systematic reviews of the evidence relating to major psychosocial risk factors to assess whether there are independent associations between any of the factors and the development and progression of coronary heart disease (CHD), or the occurrence of acute cardiac events. The expert group concluded that (i) there is strong and consistent evidence of an independent causal association between depression, social isolation and lack of quality social support and the causes and prognosis of CHD; and (ii) there is no strong or consistent evidence for a causal association between chronic life events, work-related stressors (job control, demands and strain), Type A behaviour patterns, hostility, anxiety disorders or panic disorders and CHD. The increased risk contributed by these psychosocial factors is of similar order to the more conventional CHD risk factors such as smoking, dyslipidaemia and hypertension. The identified psychosocial risk factors should be taken into account during individual CHD risk assessment and management, and have implications for public health policy and research.

Risk factors for non-haemorrhagic stroke in patients with coronary heart disease and the effect of lipid-modifying therapy with pravastatin

OBJECTIVE

To determine the relative importance of recognised risk factors for non-haemorrhagic stroke, including serum cholesterol and the effect of cholesterol-lowering therapy, on the occurrence of non-haemorrhagic stroke in patients enrolled in the LIPID (Long-term Intervention with Pravastatin in Ischaemic Disease) study.

DESIGN

The LIPID study was a placebo-controlled, double-blind trial of the efficacy on coronary heart disease mortality of pravastatin therapy over 6 years in 9014 patients with previous acute coronary syndromes and baseline total cholesterol of 4-7 mmol/l. Following identification of patients who had suffered non-haemorrhagic stroke, a pre-specified secondary end point, multivariate Cox regression was used to determine risk in the total population. Time-to-event analysis was used to determine the effect of pravastatin therapy on the rate of non-haemorrhagic stroke.

RESULTS

There were 388 non-haemorrhagic strokes in 350 patients. Factors conferring risk of future non-haemorrhagic stroke were age, atrial fibrillation, prior stroke, diabetes, hypertension, systolic blood pressure, cigarette smoking, body mass index, male sex and creatinine clearance. Baseline lipids did not predict non-haemorrhagic stroke. Treatment with pravastatin reduced non-haemorrhagic stroke by 23% (P = 0.016) when considered alone, and 21% (P = 0.024) after adjustment for other risk factors.

CONCLUSIONS

The study confirmed the variety of risk factors for non-haemorrhagic stroke. From the risk predictors, a simple prognostic index was created for non-haemorrhagic stroke to identify a group of patients at high risk. Treatment with pravastatin resulted in significant additional benefit after allowance for risk factors.

Cholesterol-lowering therapy with pravastatin in patients with average cholesterol levels and established ischaemic heart disease: is it cost-effective?

OBJECTIVE

To measure the cost-effectiveness of cholesterol-lowering therapy with pravastatin in patients with established ischaemic heart disease and average baseline cholesterol levels.

DESIGN

Prospective economic evaluation within a double-blind randomised trial (Long-Term Intervention with Pravastatin in Ischaemic Disease [LIPID]), in which patients with a history of unstable angina or previous myocardial infarction were randomised to receive 40 mg of pravastatin daily or matching placebo.

PATIENTS AND SETTING

9014 patients aged 35-75 years from 85 centres in Australia and New Zealand, recruited from June 1990 to December 1992.

MAIN OUTCOME MEASURES

Cost per death averted, cost per life-year gained, and cost per quality-adjusted life-year gained, calculated from measures of hospitalisations, medication use, outpatient visits, and quality of life.

RESULTS

The LIPID trial showed a 22% relative reduction in all-cause mortality (P < 0.001). Over a mean follow-up of 6 years, hospital admissions for coronary heart disease and coronary revascularisation were reduced by about 20%. Over this period, pravastatin cost $A4913 per patient, but reduced total hospitalisation costs by $A1385 per patient and other long-term medication costs by $A360 per patient. In a subsample of patients, average quality of life was 0.98 (where 0 = dead and 1 = normal good health); the treatment groups were not significantly different. The absolute reduction in all-cause mortality was 3.0% (95% CI, 1.6%-4.4%), and the incremental cost was $3246 per patient, resulting in a cost per life saved of $107 730 (95% CI, $68 626-$209 881) within the study period. Extrapolating long-term survival from the placebo group, the undiscounted cost per life-year saved was $7695 (and $10 938 with costs and life-years discounted at an annual rate of 5%).

CONCLUSIONS

Pravastatin therapy for patients with a history of myocardial infarction or unstable angina and average cholesterol levels reduces all-cause mortality and appears cost effective compared with accepted treatments in high-income countries.