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Biomedical subjects

Andrew M Tonkin

Publications and source records attributed to Andrew M Tonkin.

28 records · Page 2Linked to original sources
PubMed2003

"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.

Anxiety Disorders↗
PubMed2003

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.

Adult↗
PubMed2002

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.

Adult↗
PubMed2002

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 approximately 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.

Acute Disease↗
PubMed2002

Coronary heart disease in patients with low LDL-cholesterol: benefit of pravastatin in diabetics and enhanced role for HDL-cholesterol and triglycerides as risk factors.

BACKGROUND: In two large secondary prevention trials of pravastatin, risk reduction was not significant in participants who had low baseline LDL-C concentrations (that is, <125 mg/dL). We conducted exploratory analyses of participant characteristics, lipid risk factors, and risk reduction in this group. METHODS AND RESULTS: Among 13 173 participants with coronary heart disease (CHD), 2607 had baseline LDL-C <125 mg/dL. Those with LDL-C <125 compared with > or =125 mg/dL were more likely to be diabetic (15% versus 9%), hypertensive (46 versus 41%), and male (89% versus 83%); they had higher triglycerides (169 versus 154 mg/dL), lower HDL-C (36.5 versus 38 mg/dL), and similar body mass index (27 kg/m2); and pravastatin lowered their LDL-C by 36 mg/dL (32%) versus 45 mg/dL (29%). During 5.8-year (mean) follow-up, HDL-C and triglycerides were both significantly stronger predictors of recurrent CHD events in participants with LDL-C <125 than > or =125 mg/dL. In diabetic participants with low LDL-C, pravastatin decreased CHD events from 34% to 22% (relative risk, 0.56; 95% CI, 0.37 to 0.83; P=0.004), significantly different from the effect in nondiabetic participants with low LDL-C (P interaction, 0.005) (event rate, 21%; relative risk, 1.06 [95% CI, 0.89 to 1.27]). There were trends toward risk reduction in smokers and in those with low HDL-C, <40 mg/dL. CONCLUSIONS: Among patients with CHD who have low LDL-C, diabetics have much higher subsequent CHD event rates than do nondiabetics. Pravastatin reduced the event rate in diabetics to that of nondiabetic participants. The results also suggest enhanced therapeutic potential for improving HDL-C and triglycerides in patients with CHD who have low LDL-C concentrations.

Adult↗
PubMed2002

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.

Aged↗