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Biomedical subjects

Andrew Tonkin

Publications and source records attributed to Andrew Tonkin.

29 records · Page 2Linked to original sources
PubMed2003

Accuracy of the Australian National Death Index: comparison with adjudicated fatal outcomes among Australian participants in the Long-term Intervention with Pravastatin in Ischaemic Disease (LIPID) study.

OBJECTIVE: To assess the accuracy of the Australian National Death Index (NDI) in identifying deaths and recording cardiovascular and cancer causes of death. METHODS: Adjudicated mortality data from Australian participants in the Long-term Intervention with Pravastatin in Ischaemic Disease (LIPID) study up until September 1999 were used as reference. Nine hundred and eighty deceased subjects and 4,841 surviving subjects were matched to the NDI by name, date of birth, date of death and postcode. Matching rigour was confirmed by manual review. Deaths ascribed to cardiovascular and cancer causes within the NDI were also compared against LIPID-adjudicated causes. RESULTS: The NDI displayed 93.7% sensitivity and 100% specificity for the identification of deaths. Mis-recording of identifiers was responsible for 69% of known deaths not matching to the NDI and, if eliminated, would have increased the sensitivity to 98.0%. Among deceased subjects who matched to the NDI, cause of death was recorded in 96.2%. The sensitivity and specificity for cardiovascular deaths were 92.5% and 89.6%, respectively, and for cancer deaths 95.2% and 99.2%, respectively. CONCLUSION: Much of the inaccuracy of the NDI could potentially be overcome by the use of unique identifiers. Among deaths identified by the NDI, those due to cardiovascular disease are more likely to be inaccurately recorded than cancer-related deaths, probably because less uncertainty surrounds the presence or absence of terminal malignant disease.

Adult↗
PubMed2003

Rationale for a trial of low-dose aspirin for the primary prevention of major adverse cardiovascular events and vascular dementia in the elderly: Aspirin in Reducing Events in the Elderly (ASPREE).

Low-dose aspirin (acetylsalicylic acid) therapy has been shown to reduce the risk of vascular events and there is increasing evidence of its potential to reduce the rate of cognitive decline in the elderly. Adverse effects including gastrointestinal and intracranial haemorrhage may offset these benefits. The balance of risks versus benefits of aspirin for the primary prevention of cardiovascular disease and vascular dementia has not been established in the elderly. There is clearly a need to conduct a study in family practice to investigate whether routine use of low-dose aspirin for the primary prevention of cardiovascular disease and vascular dementia in the elderly is beneficial or harmful. Aspirin in reducing events in the elderly (ASPREE) is a placebo-controlled trial of low-dose aspirin for the primary prevention of major adverse cardiovascular events and vascular dementia. It will follow 15,000 subjects aged 70 years or more for an average of 5 years. This sample size has a power of 87% to detect a 15% reduction in primary events in the aspirin group, with an anticipated combined primary event rate of 20 per 1000 patient years.

Aged↗
PubMed2003

Secondary prevention of cardiovascular events with long-term pravastatin in patients with diabetes or impaired fasting glucose: results from the LIPID trial.

OBJECTIVE: Diabetes, a major health problem worldwide, increases the risk of cardiovascular disease and its associated mortality: The Long-Term Intervention with Pravastatin in Ischemic Disease (LIPID) trial showed that cholesterol-lowering treatment with pravastatin reduced mortality and coronary heart disease (CHD) events in 9014 patients aged 31-75 years with CHD and total cholesterol 4.0-7.0 mmol/l. We measured the effects of pravastatin therapy, 40 mg/day over 6.0 years, on the risk of CHD death or nonfatal myocardial infarction and other cardiovascular outcomes in 1,077 LIPID patients with diabetes and 940 patients with impaired fasting glucose (IFG). RESULTS: In patients allocated to placebo, the risk of a major CHD event was 61% higher in patients with diabetes and 23% higher in the IFG group than in patients with normal fasting glucose, and the risk of any cardiovascular event was 37% higher in the diabetic group and 19% higher in the IFG group. Pravastatin therapy reduced the risk of a major CHD event overall from 15.9 to 12.3% (relative risk reduction [RRR] 24%, P < 0.001) and from 23.4 to 19.6% in the diabetic group (19%, P = 0.11); in the diabetic group, the reduction was not significantly different from the reductions in the other groups. Pravastatin reduced the risk of any cardiovascular event from 52.7 to 45.2% (21%, P < 0.008) in patients with diabetes and from 45.7 to 37.1% (26%, P = 0.003) in the IFG group. Pravastatin reduced the risk of stroke from 9.9 to 6.3% in the diabetic group (RRR 39%, CI 7-61%, P = 0.02) and from 5.4 to 3.4% in the IFG group (RRR 42%, CI -9 to 69%, P = 0.09). Pravastatin did not reduce the incidence of diabetes. Over 6 years, pravastatin therapy prevented one major CHD event (CHD death or nonfatal myocardial infarction) in 23 patients with IFG and 18 patients with diabetes. A meta-analysis of other major trials confirmed the high absolute risks of diabetes and IFG and the absolute benefits of statin therapy in these patients. CONCLUSIONS: Cholesterol-lowering treatment with pravastatin therapy prevents cardiovascular events, including stroke, in patients with diabetes or IFG and established CHD.

Adult↗
PubMed2002

Safety and tolerability of pravastatin in long-term clinical trials: prospective Pravastatin Pooling (PPP) Project.

BACKGROUND: Therapeutic decisions regarding pharmacological therapy should be based on safety and tolerability as well as efficacy data. Clinical trials designed to assess efficacy are often insufficiently powered to generate reliable safety data. METHODS AND RESULTS: The West of Scotland Coronary Prevention Study (WOSCOPS), the Cholesterol and Recurrent Events (CARE), and Long-term Intervention with Pravastatin in Ischemic Disease (LIPID) studies collectively accumulated >112 000 person-years of exposure in double-blind randomized trials comparing placebo and pravastatin (40 mg once daily). During 5 years of exposure, the incidence of fatal and nonfatal cancers was similar between pravastatin and placebo groups. No differences in noncardiovascular serious adverse events were detected. With >243 000 blood sample analyses, the percentage of patients with any abnormal liver function test after baseline sampling was similar (>3x the upper limit of normal for alanine aminotransferase: 128 [1.4%] versus 131 [1.4%] patients for pravastatin versus placebo, respectively). Study medication was withdrawn in 3 pravastatin and 7 placebo patients due to creatine phosphokinase elevations; no cases of mild or severe myopathy were reported. A Cox regression model considering treatment group, age, diabetes, smoking, whether primary or secondary prevention study, and cardiovascular serious adverse events indicates that the likelihood of discontinuing pravastatin was less than placebo. CONCLUSIONS: This prospective analysis indicates that during prolonged exposure, 40 mg of pravastatin is well tolerated, with no excess of noncardiovascular serious adverse events, including liver function abnormalities and laboratory and clinical evidence for myositis. These extensive safety and tolerability data provide important information for therapeutic decisions regarding this pharmacological agent.

Aged↗
PubMed2002

Relationship between lipid levels and clinical outcomes in the Long-term Intervention with Pravastatin in Ischemic Disease (LIPID) Trial: to what extent is the reduction in coronary events with pravastatin explained by on-study lipid levels?

BACKGROUND: The Long-Term Intervention with Pravastatin in Ischemic Disease (LIPID) trial showed that pravastatin significantly reduced mortality and coronary heart disease (CHD) events in 9014 patients with known CHD and total cholesterol 4.0 to 7.0 mmol/L at baseline. Secondary objectives included assessment of CHD event reduction according to lipid levels. METHODS AND RESULTS: We investigated the relationships of baseline and on-study lipids with subsequent CHD events in separate Cox models. Treatment effect on CHD event reduction was examined by baseline lipids and after adjustment for on-study lipid levels. Baseline lipids were significant predictors of CHD events. The adjusted relative risk per mmol/L (on placebo) was 1.24 (P=0.004) for total cholesterol, 1.28 (P=0.002) for low-density lipoprotein cholesterol, and 0.52 (P=0.004) for high-density lipoprotein cholesterol. Apolipoproteins A1 and B were strong predictors (each P=0.001). Pravastatin reduced the risk of the composite outcome of fatal CHD or nonfatal myocardial infarction by 24% (95% confidence interval [CI], 15% to 32%) and the expanded end point of fatal CHD, nonfatal myocardial infarction, unstable angina, or coronary revascularization by 17% (95% CI, 10% to 24%). Similar relative effects were observed for different categories of baseline lipids. The proportion of treatment effect explained by on-study lipid levels was 67% (95% CI, 27% to 106%) for the composite and 97% (95% CI, 49% to 145%) for the expanded end point. The most important lipids associated with event reduction were apolipoprotein B, low-density lipoprotein cholesterol, and the combination of total and high-density lipoprotein cholesterol. CONCLUSIONS: Changes in lipid levels can explain all or most of the observed benefit of pravastatin. Some treatment effect may also be mediated through nonlipid changes.

Adult↗
PubMed2002

Dose-dependent effects of folic acid on plasma homocysteine in a randomized trial conducted among 723 individuals with coronary heart disease.

AIMS: To determine the effects on homocysteine levels of two doses of folic acid compared to placebo, where the high dose is typical of that provided by pharmacological intervention and the low dose approximates that provided by dietary supplementation. METHODS AND RESULTS: The PACIFIC study was a double-blind, placebo-controlled, factorial randomized trial. Seven hundred and twenty-three individuals with a history of myocardial infarction or unstable angina were recruited from 28 clinical cardiology centres in Australia and New Zealand and randomized to folic acid 2.0 mg daily, folic acid 0.2 mg daily or placebo. The primary outcome, homocysteine, was measured using a fluorescence polarization immunoassay. Compared to placebo, 2.0 mg folic acid reduced homo-cysteine by 1.8 micromol x 1(-1) [95% confidence interval (CI) 1.3-2.3] and 0.2 mg reduced homocysteine by 1.2 micromol x 1(-1) [95% CI 0.8-1.7). The higher dose reduced homocysteine significantly more than the lower dose (P=001). CONCLUSIONS: Both doses of folic acid reduced homocysteine, but the effects of the 2.0 mg dose were about one third greater than the 0.2 mg dose. Fortification of foods with folic acid should result in population-wide lower levels of homocysteine but high-dose pharmacological supplementation would produce greater reductions for high-risk individuals.

Aged↗
PubMed2002

Effects of the vasopeptidase inhibitor, omapatrilat, in 723 patients with coronary heart disease.

INTRODUCTION: Among individuals with a history of myocardial infarction (MI), higher levels of blood pressure (BP) are associated with increased long-term risks of death from coronary heart disease. Treatment with a BP-lowering regimen, based on omapatrilat may result in greater clinical benefits than treatment with a regimen based on a regular angiotensin-converting enzyme (ACE) inhibitor because of more favourable effects on the renin-angiotensin-aldosterone system. METHODS: Seven hundred and twenty-three clinically stable patients with a history of MI or unstable angina, and a mean entry BP of 134/77 mmHg, were randomised to six months treatment with omapatrilat 40 mg, omapatrilat 20 mg, or matching placebo. RESULTS: After six months, mean BP levels (systolic/diastolic) in the omapatrilat 40 mg group were reduced by 4.3/2.9 mmHg (95% confidence interval 1.3 to 7.2/1.2 to 4.6). Mean BP levels in the omapatrilat 20 mg group were reduced by 4.6/1.0 mmHg (1.6 to 7.6/ 0.7 to 2.6) in comparison with the placebo group. Both doses of omapatrilat also produced significant decreases in plasma ACE activity and significant increases in levels of plasma renin activity, atrial natriuretic peptide, endothelin and homocysteine (p<0.05 for all). Premature discontinuations were more frequent with omapatrilat than with placebo (p<0.001 for 20 mg and 40 mg). CONCLUSIONS: Omapatrilat produced changes in BP, neurohormone and biochemical parameters that were similar for the two doses. The long-term clinical implications of the observed effects are uncertain and a large-scale randomised trial would be required to reliably establish the effects of omapatrilat on the risks of major vascular disease events among patients with coronary heart disease.

Aged↗
PubMedDate not supplied

Nursing sans frontières: a three year case study of multi-state registration to support nursing practice using information technology.

OBJECTIVE: To highlight the registration issues for nurses who wish to practice nationally, particularly those practicing within the telehealth sector. DESIGN: As part of a national clinical research study, applications were made to every state and territory for mutual recognition of nursing registration and fee waiver for telenursing cross border practice for a period of three years. These processes are described using a case study approach. OUTCOME: The aim of this case study was to achieve registration in every state and territory of Australia without paying multiple fees by using mutual recognition provisions and the cross-border fee waiver policy of the nurse regulatory authorities in order to practice telenursing. RESULTS: Mutual recognition and fee waiver for cross-border practice was granted unconditionally in two states: Victoria (Vic) and Tasmania (Tas), and one territory: the Northern Territory (NT). The remainder of the Australian states and territories would only grant temporary registration for the period of the project or not at all, due to policy restrictions or nurse regulatory authority (NRA) Board decisions. As a consequence of gaining fee waiver the annual cost of registration was a maximum of dollars 145 per annum as opposed to the potential dollars 959 for initial registration and dollars 625 for annual renewal. CONCLUSIONS: Having eight individual nurses Acts and NRAs for a population of 265,000 nurses would clearly indicate a case for over regulation in this country. The structure of regulation of nursing in Australia is a barrier to the changing and evolving role of nurses in the 21st century and a significant factor when considering workforce planning.

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