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Biomedical subjects

P R Jackson

Publications and source records attributed to P R Jackson.

At least 19 recordsLinked to original sources
PubMed2001

Is coronary risk an accurate surrogate for cardiovascular risk for treatment decisions in mild hypertension? A population validation.

OBJECTIVE: To examine the relationship between coronary (CHD) and cardiovascular (CVD) risk in patients with uncomplicated mild hypertension and to determine the accuracy of using CHD risk > or = 15% over 10 years to identify for antihypertensive treatment those patients with CVD risk > or = 20% over 10 years as advised in recent British guidelines. DESIGN: Comparison of decisions made using CHD risk > or = 15% over 10 years calculated by the Framingham risk function and estimated using a simple table with CVD risk > or = 20% over 10 years. SETTING: British population. SUBJECTS: People aged 35-64 years with uncomplicated mild systolic hypertension (SBP 140-159 mmHg, n = 624) from the 1995 Scottish Health Survey. MAIN OUTCOME MEASURES: Relationship between CHD and CVD risk. Sensitivity, specificity, positive and negative predictive values (PPV and NPV). RESULTS: CHD risk 15% over 10 years was equivalent to CVD risk 21% over 10 years. Exact CHD risk > or = 15% over 10 years had sensitivity 79%, specificity 98%, PPV 94% and NPV 93% in detecting CVD risk > or = 20% over 10 years. Use of the table to estimate CHD risk > or = 15% over 10 years gave sensitivity 88%, specificity 90%, PPV 76% and NPV 95%. CONCLUSION: CHD risk appears acceptably accurate for targeting treatment in mild hypertension. The risk assessment table, which slightly overestimates CHD risk, was more sensitive in identifying patients with CVD risk > or = 20% over 10 years and may be preferable to using exact CHD risk. European guidelines which suggest targeting treatment for mild hypertension at CHD risk > or = 20% over 10 years are over-conservative compared with British guidelines.

Adult↗
PubMed2001

Aspirin for primary prevention of coronary heart disease: safety and absolute benefit related to coronary risk derived from meta-analysis of randomised trials.

OBJECTIVE: To determine the cardiovascular and coronary risk thresholds at which aspirin for primary prevention of coronary heart disease is safe and worthwhile. DESIGN: Meta-analysis of four randomised controlled trials of aspirin for primary prevention. The benefit and harm from aspirin treatment were examined to determine: (1) the cardiovascular and coronary risk threshold at which benefit in prevention of myocardial infarction exceeds harm from significant bleeding; and (2) the absolute benefit expressed as number needed to treat (NNT) for aspirin net of cerebral haemorrhage and other bleeding complications at different levels of coronary risk. MAIN OUTCOME MEASURES: Benefit from aspirin, expressed as reduction in cardiovascular events, myocardial infarctions, strokes, and total mortality; harm caused by aspirin in relation to significant bleeds and major haemorrhages. RESULTS: Aspirin for primary prevention significantly reduced all cardiovascular events by 15% (95% confidence interval (CI) 6% to 22%) and myocardial infarctions by 30% (95% CI 21% to 38%), and non-significantly reduced all deaths by 6% (95% CI -4% to 15%). Aspirin non-significantly increased strokes by 6% (95% CI -24% to 9%) and significantly increased bleeding complications by 69% (95% CI 38% to 107%). The risk of major bleeding balanced the reduction in cardiovascular events when cardiovascular event risk was 0.22%/year. The upper 95% CI for this estimate suggests that harm from aspirin is unlikely to outweigh benefit provided the cardiovascular event risk is 0.8%/year, equivalent to a coronary risk of 0.6%/year. At coronary event risk 1.5%/year, the five year NNT was 44 to prevent a myocardial infarction, and 77 to prevent a myocardial infarction net of any important bleeding complication. At coronary event risk 1%/year the NNT was 67 to prevent a myocardial infarction, and 182 to prevent a myocardial infarction net of important bleeding. CONCLUSIONS: Aspirin treatment for primary prevention is safe and worthwhile at coronary event risk >/= 1.5%/year; safe but of limited value at coronary risk 1%/year; and unsafe at coronary event risk 0.5%/year. Advice on aspirin for primary prevention requires formal accurate estimation of absolute coronary event risk.

Aspirin↗
PubMed2000

Coronary and cardiovascular risk estimation for primary prevention: validation of a new Sheffield table in the 1995 Scottish health survey population.

OBJECTIVE: To examine the accuracy of a new version of the Sheffield table designed to aid decisions on lipids screening and detect thresholds for risk of coronary heart disease needed to implement current guidelines for primary prevention of cardiovascular disease. DESIGN: Comparison of decisions made on the basis of the table with absolute risk of coronary heart disease or cardiovascular disease calculated by the Framingham risk function. The decisions related to statin treatment when coronary risk is >/=30% over 10 years; aspirin treatment when the risk is >/=15% over 10 years; and the treatment of mild hypertension when the cardiovascular risk is >/=20% over 10 years. SETTING: The table is designed for use in general practice. SUBJECTS: Random sample of 1000 people aged 35-64 years from the 1995 Scottish health survey. MAIN OUTCOME MEASURES: Sensitivity, specificity, and positive and negative predictive values of the table. RESULTS: 13% of people had a coronary risk of >/=15%, and 2. 2% a risk of >/=30%, over 10 years. 22% had mild hypertension (systolic blood pressure 140-159 mm Hg). The table indicated lipids screening for everyone with a coronary risk of >/=15% over 10 years, for 95% of people with a ratio of total cholesterol to high density lipoprotein cholesterol of >/=8.0, but for <50% with a coronary risk of <5% over 10 years. Sensitivity and specificity were 97% and 95% respectively for a coronary risk of >/=15% over 10 years; 82% and 99% for a coronary risk of >/=30% over 10 years; and 88% and 90% for a cardiovascular risk of >/=20% over 10 years in mild hypertension. CONCLUSION: The table identifies all high risk people for lipids screening, reduces screening of low risk people by more than half, and ensures that treatments are prescribed appropriately to those at high risk, while avoiding inappropriate treatment of people at low risk.

Adult↗
PubMed2000

Lean production teams and health in garment manufacture.

The impact of lean production on psychological health was assessed by comparing lean production teams in garment manufacture with a traditional system for making similar garments. Work design characteristics were examined as mediators of the impact of work organization on health. Findings indicate both positive and negative direct effects of teamworking on aspects of autonomy, work demands, and social climate. In turn, both positive and negative direct effects of work design on psychological health were found, which combine to give no overall difference between the groups. This study suggests that the balance between positive and negative effects of lean production teamworking depends on management choices in the form of work design.

Adolescent↗
PubMed2000

Debate: at what level of coronary heart disease risk should a statin be prescribed?

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) are effective treatments for the primary and secondary prevention of coronary heart disease, but an outstanding issue is determining who should have such treatment. The benefit from treatment with statins appears to be proportional to the underlying risk of coronary heart disease and independent of the factors increasing risk. Most benefit will therefore be achieved by treating people at increased risk of coronary heart disease. Statins reduce coronary morbidity even when the risk of coronary heart disease is relatively low (6% over 10 years), but reduction in all-cause mortality, the true measure of safety has been shown only when the risk of a major coronary heart disease event is 15% over 10 years or greater. At this level of risk patients appear willing to take treatment to gain the benefit expected from statin treatment, and the cost effectiveness of statin treatment is within the range accepted for other treatments. The major impediments to the systematic introduction of statin treatment at this level of risk are the very high overall cost and the large workload in countries like Britain, where the population risk of coronary heart disease is high. For this reason, recent British guidelines correctly advise statin treatment for secondary prevention and primary prevention when the 10 year coronary heart disease risk is 30% or greater as the first priority, moving to a lower coronary heart disease threshold for primary prevention only when resources permit.

Coronary Disease↗
PubMed1999

Association of panic disorder and panic attacks with hypertension.

PURPOSE: Previous studies of the association between hypertension and panic disorder were uncontrolled or involved small numbers of patients. PATIENTS AND METHODS: We compared the prevalence of panic disorder and panic attacks in 351 patients with documented hypertension who were randomly selected from all hypertensive patients registered in one primary care practice with age- and gender-matched normotensive patients from the same practice and with hypertensive patients attending a hospital clinic. All three groups completed questionnaires for panic disorder based on standard criteria, as well as the Hospital Anxiety and Depression scale. RESULTS: The prevalence of current (previous 6 months) panic attacks was significantly greater in primary care patients with hypertension (17%, P <0.05) and hospital-based hypertensive patients (19%, P <0.01) than in normotensive patients (11%). Similar results were seen for lifetime panic attacks (35% versus 39% versus 22%; both P for comparisons with normotensive patients <0.001). The prevalence of panic disorder was significantly greater in primary care patients with hypertension (13%) than normotensive patients (8%, P <0.05). Anxiety scores were significantly higher in both hypertensive groups than in normotensive patients. Depression scores were significantly higher in hospital-based hypertensive patients than in the other two groups. The reported diagnosis of hypertension antedated the onset of panic attacks in a large majority of patients (P <0.01). CONCLUSIONS: Physicians caring for patients with hypertension should be aware of the significantly greater prevalence of panic attacks in these patients.

Aged↗
PubMed1999

Prediction of coronary risk for primary prevention of coronary heart disease: a comparison of methods.

Most recent guidelines advise targeting of lipid lowering for primary prevention at those at high absolute coronary (CHD) risk. We compared the accuracy of five CHD risk assessment methods in identifying such patients: one based on total cholesterol > or = 6.5 mmol/l plus two risk factors, and four based on the Framingham risk function (the European Task Force chart and Sheffield table, both using total cholesterol and the New Zealand chart and modified Sheffield table, both using total: HDL cholesterol ratio) for predicting CHD event risk > or = 2% per year, calculated by an independent risk function, PROCAM, in 126 treated hypertensive men. Cholesterol threshold plus two risk factors had sensitivity 59% and specificity 63%, did not identify some very high-risk patients, and identified very low-risk patients. Framingham-based methods using total cholesterol alone had sensitivity 90-98% and specificity 37-43%, and identified high-risk patients well, but identified some patients at very low risk. Methods based on total: HDL cholesterol ratio had sensitivity 90-98% and specificity 60-63%, and did not identify incorrectly patients at very low CHD risk. Methods based on cholesterol threshold and counting of risk factors are too inaccurate for targeting drug therapy for primary prevention of CHD. Framingham-based methods should incorporate HDL-cholesterol as the total: HDL cholesterol ratio.

Cholesterol↗
PubMed1999

Implication of recent trials with b-hydroxy-b-methylglutaryl coenzyme A reductase inhibitors for hypertension management.

BACKGROUND: There is broad agreement that statin treatment should be targeted at absolute coronary heart disease (CHD) risk but no consensus on the level of risk to target. We have examined the implications of adopting three different treatment policies for the management of hypertensive patients in the UK using data from treated hypertensives aged 35-69 years included in the Health Survey for England (1993). METHODS: We calculated the proportion of hypertensive patients with existing atherosclerotic cardiovascular disease requiring statin treatment for secondary prevention of CHD. For those without atherosclerotic cardiovascular disease (primary prevention), we estimated CHD risk from the Framingham equation and examined the proportion with CHD risk exceeding thresholds of 4.5, 3 and 1.5% per year. RESULTS: Twenty-one percent of treated hypertensives would require statin treatment for secondary prevention of CHD. When the CHD event threshold for statin treatment was set at > or =4.5% per year [equivalent to a number needed to treat (NNT) in 5 years of 13] a further 0.6% of hypertensive patients were identified for treatment; at a threshold of 3.0% per year (NNT = 20) 5.5% of patients were identified for primary prevention; and at a threshold of 1.5% per year (NNT = 40) 28.5% of patients were identified for primary prevention. CONCLUSIONS: Those needing secondary prevention are first priority for statins and 21% of hypertensive patients will require treatment Formulation of guidelines for primary prevention should take into account the NNT; the proportion of patients targeted for treatment; the cost-effectiveness and the total cost of treatment. Current British guidance will entail treating an additional 5.5% of hypertensive patients for primary prevention and therefore 27% of hypertensive patients.

Aged↗
PubMed1999

Is the Framingham risk function valid for northern European populations? A comparison of methods for estimating absolute coronary risk in high risk men.

OBJECTIVE: To examine the validity of estimates of coronary heart disease (CHD) risk by the Framingham risk function, for European populations. DESIGN: Comparison of CHD risk estimates for individuals derived from the Framingham, prospective cardiovascular Münster (PROCAM), Dundee, and British regional heart (BRHS) risk functions. SETTING: Sheffield Hypertension Clinic. Patients-206 consecutive hypertensive men aged 35-75 years without preexisting vascular disease. RESULTS: There was close agreement among the Framingham, PROCAM, and Dundee risk functions for average CHD risk. For individuals the best correlation was between Framingham and PROCAM, both of which use high density lipoprotein (HDL) cholesterol. When Framingham was used to target a CHD event rate > 3% per year, it identified men with mean CHD risk by PROCAM of 4.6% per year and all had CHD event risks > 1.5% per year. Men at lower risk by Framingham had a mean CHD risk by PROCAM of 1.5% per year, with 16% having a CHD event risk > 3.0% per year. BRHS risk function estimates of CHD risk were fourfold lower than those for the other three risk functions, but with moderate correlations, suggesting an important systematic error. CONCLUSION: There is close agreement between the Framingham, PROCAM, and Dundee risk functions as regards average CHD risk, and moderate agreement for estimates within individuals. Taking PROCAM as the external standard, the Framingham function separates high and low CHD risk groups and is acceptably accurate for northern European populations, at least in men.

Adult↗
PubMed1999

Cost effectiveness of HMG-CoA reductase inhibitor (statin) treatment related to the risk of coronary heart disease and cost of drug treatment.

OBJECTIVES: To estimate the cost effectiveness of statin treatment in preventing coronary heart disease (CHD) and to examine the effect of the CHD risk level targeted and the cost of statins on the cost effectiveness of treatment. DESIGN: Cohort life table method using data from outcome trials. MAIN OUTCOME MEASURES: The cost per life year gained for lifelong statin treatment at annual CHD event risks of 4.5% (secondary prevention) and 3.0%, 2.0%, and 1.5% (all primary prevention), with the cost of statins varied from pound 100 to pound 800 per year. RESULTS: The costs per life year gained according to annual CHD event risk were: for 4.5%, pound 5100; 3.0%, pound 8200; 2.0%, pound 10 700; and 1.5%, pound 12 500. Reducing the cost of statins increases cost effectiveness, and narrows the difference in cost effectiveness across the range of CHD event risks. CONCLUSIONS: At current prices statin treatment for secondary prevention, and for primary prevention at a CHD event risk 3.0% per year, is as cost effective as many treatments in wide use. Primary prevention at lower CHD event risks (< 3.0% per year) is less cost effective and unlikely to be affordable at current prices and levels of health service funding. As the cost of statins falls, primary prevention at lower risk levels becomes more cost effective. However, the large volume of treatment needed will remain a major problem.

Coronary Disease↗