Andrew Tonkin

Risk of Cardiovascular and All-Cause Mortality in Individuals With Diabetes Mellitus, Impaired Fasting Glucose, and Impaired Glucose Tolerance The Australian Diabetes, Obesity, and Lifestyle Study (AusDiab)

Background— Diabetes mellitus increases the risk of cardiovascular disease (CVD) and all-cause mortality. The relationship between milder elevations of blood glucose and mortality is less clear. This study investigated whether impaired fasting glucose and impaired glucose tolerance, as well as diabetes mellitus, increase the risk of all-cause and CVD mortality. Methods and Results— In 1999 to 2000, glucose tolerance status was determined in 10 428 participants of the Australian Diabetes, Obesity, and Lifestyle Study (AusDiab). After a median follow-up of 5.2 years, 298 deaths occurred (88 CVD deaths). Compared with those with normal glucose tolerance, the adjusted all-cause mortality hazard ratios (HRs) and 95% confidence intervals (CIs) for known diabetes mellitus and newly diagnosed diabetes mellitus were 2.3 (1.6 to 3.2) and 1.3 (0.9 to 2.0), respectively. The risk of death was also increased in those with impaired fasting glucose (HR 1.6, 95% CI 1.0 to 2.4) and impaired glucose tolerance (HR 1.5, 95% CI 1.1 to 2.0). Sixty-five percent of all those who died of CVD had known diabetes mellitus, newly diagnosed diabetes mellitus, impaired fasting glucose, or impaired glucose tolerance at baseline. Known diabetes mellitus (HR 2.6, 95% CI 1.4 to 4.7) and impaired fasting glucose (HR 2.5, 95% CI 1.2 to 5.1) were independent predictors for CVD mortality after adjustment for age, sex, and other traditional CVD risk factors, but impaired glucose tolerance was not (HR 1.2, 95% CI 0.7 to 2.2). Conclusions— This study emphasizes the strong association between abnormal glucose metabolism and mortality, and it suggests that this condition contributes to a large number of CVD deaths in the general population. CVD prevention may be warranted in people with all categories of abnormal glucose metabolism.

Association of LDL Cholesterol, Non–HDL Cholesterol, and Apolipoprotein B Levels With Risk of Cardiovascular Events Among Patients Treated With Statins: A Meta-analysis

CONTEXT The associations of low-density lipoprotein cholesterol (LDL-C), non-high-density lipoprotein cholesterol (non-HDL-C), and apolipoprotein B (apoB) levels with the risk of cardiovascular events among patients treated with statin therapy have not been reliably documented. OBJECTIVE To evaluate the relative strength of the associations of LDL-C, non-HDL-C, and apoB with cardiovascular risk among patients treated with statin therapy. DESIGN Meta-analysis of individual patient data from randomized controlled statin trials in which conventional lipids and apolipoproteins were determined in all study participants at baseline and at 1-year follow-up. DATA SOURCES Relevant trials were identified by a literature search updated through December 31, 2011. Investigators were contacted and individual patient data were requested and obtained for 62,154 patients enrolled in 8 trials published between 1994 and 2008. DATA EXTRACTION Hazard ratios (HRs) and corresponding 95% CIs for risk of major cardiovascular events adjusted for established risk factors by 1-SD increase in LDL-C, non-HDL-C, and apoB. RESULTS Among 38,153 patients allocated to statin therapy, 158 fatal myocardial infarctions, 1678 nonfatal myocardial infarctions, 615 fatal events from other coronary artery disease, 2806 hospitalizations for unstable angina, and 1029 fatal or nonfatal strokes occurred during follow-up. The adjusted HRs for major cardiovascular events per 1-SD increase were 1.13 (95% CI, 1.10-1.17) for LDL-C, 1.16 (95% CI, 1.12-1.19) for non-HDL-C, and 1.14 (95% CI, 1.11-1.18) for apoB. These HRs were significantly higher for non-HDL-C than LDL-C (P = .002) and apoB (P = .02). There was no significant difference between apoB and LDL-C (P = .21). CONCLUSION Among statin-treated patients, on-treatment levels of LDL-C, non-HDL-C, and apoB were each associated with risk of future major cardiovascular events, but the strength of this association was greater for non-HDL-C than for LDL-C and apoB.

Effect of Pravastatin on Coronary Disease Events in Subgroups Defined by Coronary Risk Factors The Prospective Pravastatin Pooling Project

BackgroundPrevious trials have had insufficient numbers of coronary events to address definitively the effect of lipid-modifying therapy on coronary heart disease in subgroups of patients with varying baseline characteristics. Methods and ResultsThe data from 3 large randomized trials with pravastatin 40 mg were pooled and analyzed with the use of a prospectively defined protocol. Included were 19 768 patients, 102 559 person-years of follow-up, 2194 primary end points (coronary death or nonfatal myocardial infarction), and 3717 expanded end points (primary end point, CABG, or PTCA). Pravastatin significantly reduced relative risk in younger (<65 years) and older (≥65 years) patients, men and women, smokers and nonsmokers, and patients with or without diabetes or hypertension. The relative effect was smaller, but absolute risk reduction was similar in patients with hypertension compared with those without hypertension. Relative risk reduction was significant in predefined categories of baseline lipid concentrations. Tests for interaction were not significant between relative risk reduction and baseline total cholesterol (5% to 95% range 177 to 297 mg/dL, 4.6 to 7.7 mmol/L), HDL cholesterol (27 to 58 mg/dL, 0.7 to 1.5 mmol/L), and triglyceride (74 to 302 mg/dL, 0.8 to 3.4 mmol/L) concentrations, analyzed as continuous variables. However, for LDL cholesterol, the probability values for interaction were 0.068 for the prespecified primary end point and 0.019 for the expanded end point. Relative risk reduction was similar throughout most of the baseline LDL cholesterol range (125 to 212 mg/dL, 3.2 to 5.5 mmol/L) with the possible exception of the lowest quintile of CARE/LIPID (<125 mg/dL) (relative risk reduction 5%, 95% CI 19% to −12%). ConclusionsPravastatin treatment is effective in reducing coronary heart disease events in patients with high or low risk factor status and across a wide range of pretreatment lipid concentrations.

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.

Effect of Pravastatin on Cardiovascular Events in People With Chronic Kidney Disease

Background—Limited data describe the cardiovascular benefit of HMG-CoA reductase inhibitors (statins) in people with moderate chronic kidney disease (CKD). The objective of this analysis was to determine whether pravastatin reduced the incidence of cardiovascular events in people with or at high risk for coronary disease and with concomitant moderate CKD. Methods and Results—We analyzed data from the Pravastatin Pooling Project (PPP), a subject-level database combining results from 3 randomized trials of pravastatin (40 mg daily) versus placebo. Of 19 700 subjects, 4491 (22.8%) had moderate CKD, defined by an estimated glomerular filtration rate of 30 to 59.99 mL/min per 1.73 m2 body surface area. The primary outcome was time to myocardial infarction, coronary death, or percutaneous/surgical coronary revascularization. Moderate CKD was independently associated with an increased risk of the primary outcome (adjusted HR 1.26, 95% CI 1.07 to 1.49) compared with those with normal renal function. Among the 4491 subjects with moderate CKD, pravastatin significantly reduced the incidence of the primary outcome (HR 0.77, 95% CI 0.68 to 0.86), similar to the effect of pravastatin on the primary outcome in subjects with normal kidney function (HR 0.78, 95% CI 0.65 to 0.94). Pravastatin also appeared to reduce the total mortality rate in those with moderate CKD (adjusted HR 0.86, 95% CI 0.74 to 1.00, P=0.045). Conclusions—Pravastatin reduces cardiovascular event rates in people with or at risk for coronary disease and concomitant moderate CKD, many of whom have serum creatinine levels within the normal range. Given the high risk associated with CKD, the absolute benefit that resulted from use of pravastatin was greater than in those with normal renal function.

Home use of automated external defibrillators for sudden cardiac arrest

BACKGROUND The most common location of out-of-hospital sudden cardiac arrest is the home, a situation in which emergency medical services are challenged to provide timely care. Consequently, home use of an automated external defibrillator (AED) might offer an opportunity to improve survival for patients at risk. METHODS We randomly assigned 7001 patients with previous anterior-wall myocardial infarction who were not candidates for an implantable cardioverter-defibrillator to receive one of two responses to sudden cardiac arrest occurring at home: either the control response (calling emergency medical services and performing cardiopulmonary resuscitation [CPR]) or the use of an AED, followed by calling emergency medical services and performing CPR. The primary outcome was death from any cause. RESULTS The median age of the patients was 62 years; 17% were women. The median follow-up was 37.3 months. Overall, 450 patients died: 228 of 3506 patients (6.5%) in the control group and 222 of 3495 patients (6.4%) in the AED group (hazard ratio, 0.97; 95% confidence interval, 0.81 to 1.17; P=0.77). Mortality did not differ significantly in major prespecified subgroups. Only 160 deaths (35.6%) were considered to be from sudden cardiac arrest from tachyarrhythmia. Of these deaths, 117 occurred at home; 58 at-home events were witnessed. AEDs were used in 32 patients. Of these patients, 14 received an appropriate shock, and 4 survived to hospital discharge. There were no documented inappropriate shocks. CONCLUSIONS For survivors of anterior-wall myocardial infarction who were not candidates for implantation of a cardioverter-defibrillator, access to a home AED did not significantly improve overall survival, as compared with reliance on conventional resuscitation methods. (ClinicalTrials.gov number, NCT00047411 [ClinicalTrials.gov].).

Rivaroxaban with or without Aspirin in Stable Cardiovascular Disease

BACKGROUND We evaluated whether rivaroxaban alone or in combination with aspirin would be more effective than aspirin alone for secondary cardiovascular prevention. METHODS In this double‐blind trial, we randomly assigned 27,395 participants with stable atherosclerotic vascular disease to receive rivaroxaban (2.5 mg twice daily) plus aspirin (100 mg once daily), rivaroxaban (5 mg twice daily), or aspirin (100 mg once daily). The primary outcome was a composite of cardiovascular death, stroke, or myocardial infarction. The study was stopped for superiority of the rivaroxaban‐plus‐aspirin group after a mean follow‐up of 23 months. RESULTS The primary outcome occurred in fewer patients in the rivaroxaban‐plus‐aspirin group than in the aspirin‐alone group (379 patients [4.1%] vs. 496 patients [5.4%]; hazard ratio, 0.76; 95% confidence interval [CI], 0.66 to 0.86; P<0.001; z=‐4.126), but major bleeding events occurred in more patients in the rivaroxaban‐plus‐aspirin group (288 patients [3.1%] vs. 170 patients [1.9%]; hazard ratio, 1.70; 95% CI, 1.40 to 2.05; P<0.001). There was no significant difference in intracranial or fatal bleeding between these two groups. There were 313 deaths (3.4%) in the rivaroxaban‐plus‐aspirin group as compared with 378 (4.1%) in the aspirin‐alone group (hazard ratio, 0.82; 95% CI, 0.71 to 0.96; P=0.01; threshold P value for significance, 0.0025). The primary outcome did not occur in significantly fewer patients in the rivaroxaban‐alone group than in the aspirin‐alone group, but major bleeding events occurred in more patients in the rivaroxaban‐alone group. CONCLUSIONS Among patients with stable atherosclerotic vascular disease, those assigned to rivaroxaban (2.5 mg twice daily) plus aspirin had better cardiovascular outcomes and more major bleeding events than those assigned to aspirin alone. Rivaroxaban (5 mg twice daily) alone did not result in better cardiovascular outcomes than aspirin alone and resulted in more major bleeding events. (Funded by Bayer; COMPASS ClinicalTrials.gov number, NCT01776424.)

Effect of Pravastatin on Rate of Kidney Function Loss in People With or at Risk for Coronary Disease

Background—Limited data suggest that HMG-CoA reductase inhibitors (statins) reduce rates of kidney function loss. We performed this analysis to determine whether pravastatin reduced the rate of kidney function loss over ≈5 years in people with or at high risk for coronary disease. Methods and Results—This was a post hoc subgroup analysis of data from 3 randomized double-blind controlled trials comparing pravastatin 40 mg/d and placebo in subjects with a previous acute coronary syndrome or who were at high cardiovascular risk. The primary outcome was the rate of change in estimated glomerular filtration rate (GFR; in mL/min per 1.73 m2/y). The Modified Diet and Renal Disease Study (MDRD) and Cockcroft-Gault equations were used to estimate GFR. We studied 18 569 participants, 3402 (18.3%) of whom had moderate chronic kidney disease as defined by an estimated GFR of 30 to 59.9 mL/min per 1.73 m2 body surface area. In subjects with moderate chronic kidney disease at baseline, pravastatin reduced the adjusted rate of kidney function loss by ≈34%, although the absolute reduction in the rate of loss was small (0.22 mL/min per 1.73 m2/y by MDRD-GFR; 95% CI, 0.07 to 0.37). Pravastatin did not reduce the frequency of ≥25% decreases in kidney function in this group when MDRD-GFR was used to estimate GFR (relative risk [RR], 0.84; 95% CI, 0.66 to 1.06). When all 18 569 subjects were considered, pravastatin reduced the adjusted rate of kidney function loss by 8% (0.08 mL/min per 1.73 m2/y by MDRD-GFR; 95% CI, 0.01 to 0.15) and the risk of acute renal failure (RR, 0.60; 95% CI, 0.41 to 0.86) but did not significantly reduce the frequency of a ≥25% decline in kidney function by MDRD-GFR (RR, 0.94; 95% CI, 0.88 to 1.01). Conclusions—Pravastatin modestly reduced the rate of kidney function loss in people with or at risk for cardiovascular disease. However, the primary indication for the use of statins in people with or at risk for coronary events remains the reduction in mortality that results from their use.

Effect of Pravastatin in People with Diabetes and Chronic Kidney Disease

Although diabetes is a major cause of chronic kidney disease (CKD), limited data describe the cardiovascular benefit of hydroxymethyl glutaryl CoA reductase inhibitors (statins) in people with both of these conditions. This study sought to determine whether pravastatin reduced the incidence of first or recurrent cardiovascular events in people with non-dialysis-dependent CKD and concomitant diabetes, using data from three randomized trials of pravastatin 40 mg daily versus placebo. CKD was defined by estimated GFR <60 or 60 to 89.9 ml/min per 1.73 m2 with proteinuria. Of 19,737 patients, 4099 (20.8%) had CKD but not diabetes at baseline, 873 (4.4%) had diabetes but not CKD, and 571 (2.9%) had both conditions. The primary composite outcome was time to myocardial infarction, coronary death, or percutaneous/surgical coronary revascularization. Median follow-up was 64 mo. After adjustment for trial and random treatment assignment, the incidence of the primary outcome was lowest in individuals with neither CKD nor diabetes (15.2%), intermediate in individuals with only CKD (18.6%) or only diabetes (21.3%), and highest in individuals with both characteristics (27.0%). Pravastatin reduced the relative likelihood of the primary outcome to a similar extent in subgroups defined by the presence or absence of CKD and diabetes. For example, pravastatin was associated with a significant reduction in the relative risk of the primary outcome by 25% in patients with CKD and concomitant diabetes and by 24% in individuals with neither characteristic. However, the absolute reduction in the risk of the primary outcome as a result of pravastatin use was highest in patients with both CKD and diabetes (6.4%) and lowest in individuals with neither characteristic (3.5%). In conclusion, stage 2 or early stage 3 CKD and diabetes both are associated with higher cardiovascular risk, and pravastatin reduces cardiovascular event rates in people with neither, one, or both characteristics. Given the high absolute benefit of pravastatin in patient with diabetes and stage 2 or early stage 3 CKD, this population in particular should be targeted for widespread use of statins. Additional studies are needed to determine whether these benefits apply to patients with more severe CKD, and recruitment to such studies should be given high priority.

Genome-Wide Linkage Analysis of the Acute Coronary Syndrome Suggests a Locus on Chromosome 2

A positive family history is a recognized cardiovascular risk factor, and genome-wide scans may reveal susceptibility loci for coronary artery disease. The acute coronary syndrome, consisting of myocardial infarction and unstable angina, is the most important manifestation of coronary disease and is characterized by atherosclerotic plaque disruption and coronary thrombosis. From ≈6000 hospital admissions to cardiology units, we identified affected sibling pairs (n=61) who had documented acute coronary syndrome before the age of 70 years. A 10-cM resolution genetic map and MAPMAKER/SIBS were used for genome-wide linkage analysis. One locus on chromosome 2q36-q37.3 showed linkage with a lod score of 2.63 (P <0.0001). Separate multipoint fine-mapping of this locus with independent markers replicated the linkage results (lod 2.64). Two other regions on chromosomes 3q26-q27 and 20q11-q13 showed lod scores in excess of 1.5 (P <0.005). This genome scan in acute coronary syndrome suggests 1 locus that encompasses the gene encoding the insulin receptor substrate-1 gene. Two other potential loci were identified. These data imply that a limited number of potent susceptibility genes exist for the acute coronary syndrome. Such genes are likely to be relevant to the combined processes of atherosclerosis, plaque instability, and coronary thrombosis.