Risk factor measurement quality in primary care routine data was variable but nondifferential between individuals.

OBJECTIVE: To retrospectively assess the quality of cardiovascular disease risk factor measurements in routinely collected data and to examine whether there are systematic differences in measurement quality between individuals of different socioeconomic status, and changes in measurement quality over time. STUDY DESIGN AND SETTING: Comparison of last digit preference in risk factor measurement between a "routine" data set (related to a primary care-based UK cardiovascular risk factor screening programme) and relevant prospective epidemiological surveys (Health Survey for England [HSE] and WHO MONICA). For the routine data set, the records of 37,161 women and 33,977 men aged 35-60 years with a first screening episode during the 11-year period 1989-1999 were analyzed. RESULTS: Last digits of height, weight, and total cholesterol measurements in the routine data set did not exhibit a digit preference pattern, although the degree of random measurement error was greater compared with epidemiological survey data. The last digits of systolic and diastolic blood pressure (BP) measurements exhibited a strong last digit preference pattern for "0"-comprising 63.1% and 67.3% of all observations in men and women, respectively. Except for diastolic BP in men, last digit distribution patterns were not associated with participant's socioeconomic status and showed no change over time. CONCLUSION: It may be feasible to study changes over time in cardiovascular disease risk factor levels in different socioeconomic groups using routine data sets; however, prior critical examination of measurement quality is necessary.

Risk of primary and recurrent acute myocardial infarction from lipoprotein(a) in men and women.

OBJECTIVES: This study sought to examine whether lipoprotein(a) concentrations were risk factors for a first acute and recurrent myocardial infarction. BACKGROUND: There is conflicting evidence concerning the risk of acute myocardial infarction from lipoprotein(a). No studies have examined the risk of recurrent acute myocardial infarction from lipoprotein(a), and few have addressed the risk in women. METHODS: This was a population-based case-control study of 893 men and women 35 to 69 years old participating in the World Health Organization Monitoring Trends and Determinants in Cardiovascular Disease (MONICA) Project in Newcastle, Australia in 1993 to 1994. Case and control patients were classified into those with and without a previous myocardial infarction, and median lipoprotein(a) concentrations were compared after adjusting for other variables. Quintiles of lipoprotein(a) concentration were also examined. RESULTS: Compared with control subjects without a previous myocardial infarction, median lipoprotein(a) concentrations increased from case patients with a first myocardial infarction (15 mg/liter higher, 95% confidence interval [CI] -36 to 60) to control patients with a previous myocardial infarction (159 mg/ liter higher, 95% CI 40 to 278) and case patients with a previous myocardial infarction (60 mg/liter higher, 95% CI -16 to 136, p < 0.01, test for trend). Women had significantly higher lipoprotein(a) concentrations than men (median 71 mg/liter higher, 95% CI 23 to 118). The highest quintile of lipoprotein(a) (>550 mg/liter) was a significant risk factor for a first acute myocardial infarction (odds ratio [OR] 1.77, 95% CI 1.03 to 3.03); but in those with a previous myocardial infarction, the highest quintile was not associated with recurrent myocardial infarction (OR 0.84, 95% CI 0.30 to 2.37). CONCLUSIONS: High lipoprotein(a) concentrations may be a marker of vascular or tissue injury or may be associated with other genetic or environmental factors that cause acute myocardial infarction. Currently, lipoprotein(a) measurement cannot be recommended for assessment of risk for acute myocardial infarction.

Survival among hospital in-patients with troponin T elevation below levels defining myocardial infarction.

BACKGROUND: Cardiac troponin T (cTnT) has an accepted place in the management of patients presenting with suspected acute coronary syndrome (ACS). Uncertainty remains about the significance and interpretation of elevated cTnT below the cut-off levels defining myocardial infarction (0.1 microg/l). AIM: To compare the mortality risks for elevation of cTnT in the ranges 0.01-0.029 microg/l, 0.03-0.099 microg/l and <0.01 microg/l. DESIGN: Retrospective record study in three hospitals. METHODS: All cTnT measurements with values in the range >0.01-0.099 microg/l analysed during January 2002 were extracted from clinical biochemistry laboratory databases. Following agreed exclusion criteria, 179 patients with cTnT in the range 0.01-0.099 microg/l and 60 patients <0.01 microg/l were selected at random from across the three sites. Six-month follow-up was completed by review of case notes and contact with the patients' GP. RESULTS: There was a graded increase in mortality with increasing cTnT, although only achieving statistical significance for patients in the 0.03-0.099 microg/l range. The graded increase in relative risk with cTnT was weaker after adjustment for potential confounding factors DISCUSSION: We found a trend for worse survival with increasing cTnT within the range 0.01-0.099 microg/l in unselected patient populations presenting with possible acute coronary syndrome. This suggests that the combined effects of assay imprecision and co-morbidity should be taken into account when interpreting borderline elevation of cTnT. The use of a cut-off based on current standards of assay precision should be used to define the sensitivity of cTnT as biochemical evidence of ischaemic cardiac damage and as an indicator of mortality risk. This level is likely to be between 0.03 and 0.1 microg/l.

Population impact of stricter adherence to recommendations for pharmacological and lifestyle interventions over one year in patients with coronary heart disease.

STUDY OBJECTIVE: To assess the potential number of lives saved associated with the full implementation of aspects of the National Service Framework (NSF) for coronary heart disease (CHD) in England using recently developed population impact measures. DESIGN: Modelling study. SETTING: Primary care. DATA SOURCES: Published data on prevalence of acute myocardial infarction and heart failure, baseline risk of mortality, the relative risk reduction associated with different interventions and the proportion treated, eligible for treatment and adhering to each intervention. MAIN RESULTS: Adopting the NSF recommendations for pharmacological interventions would prevent an extra 1027 (95% CI 418 to 1994) deaths in post-acute myocardial infarction (AMI) patients and an extra 37 899 (95% CI 25 690 to 52 503) deaths in heart failure patients in the first year after diagnosis. Lifestyle based interventions would prevent an extra 848 (95% CI 71 to 1 614) deaths in post-AMI patients and an extra 7249 (95% CI 995 to 16 696) deaths in heart failure patients. CONCLUSIONS: Moving from current to "best" practice as recommended in the NSF will have a much greater impact on one year mortality rates among heart failure patients compared with post-AMI patients. Meeting pharmacological based recommendations for heart failure patients will prevent more deaths than meeting lifestyle based recommendations. Population impact numbers can help communicate the impact on a population of the implementation of guidelines and, when created using local data, could help policy makers assess the local impact of implementing a range of health care targets.

The impact of diabetes on survival among patients with first myocardial infarction.

OBJECTIVE: The purpose of this paper is to estimate the impact of diabetes on survival among patients with first acute myocardial infarction, using data from the World Health Organization (WHO) Monitoring Trends and Determinants of Cardiovascular Disease (MONICA) Project in Newcastle, New South Wales, Australia. RESEARCH DESIGN AND METHODS: The WHO MONICA Project is a community-based surveillance system that monitors coronary heart disease morbidity and mortality. All patients with suspected coronary events were observed for 28 days after the onset of symptoms. RESULTS: Of 5,322 patients with acute myocardial infarction and no previous history of ischemic heart disease (3,643 men and 1,679 women), 333 men (9%) and 224 women (13%) had a history of diabetes. The age-adjusted 28-day case fatality for women with diabetes (25%) was significantly higher than for women without diabetes (16%); relative risk 1.56 (95% CI: 1.19-2.04). The difference for men was also significant (25% with diabetes and 20% without diabetes); relative risk 1.25 (95% CI: 1.02-1.53). Age-specific case fatality increased significantly with age in both men and women without diabetes, but systematic age effects were not so apparent in patients with diabetes. Case fatality significantly decreased over the study period in patients without diabetes, but not among the diabetic patients. CONCLUSIONS: The increased risk of death in the diabetic patients remained after accounting for their poorer risk factor profiles; even if they reached the hospital alive, diabetic patients were also less likely to survive than nondiabetic patients. The relative impact of diabetes on survival is greater in women than in men.

Knowledge of stroke risk factors, warning symptoms, and treatment among an Australian urban population.

BACKGROUND AND PURPOSE: Reduction in the risk of stroke and increase in the speed of hospital presentation after the onset of stroke both depend on the level of knowledge of stroke in the general population. The aim of the present study was to assess baseline knowledge regarding stroke risk factors, symptoms, treatment, and information resources. METHODS: A community-based telephone interview survey was conducted in the Newcastle urban area in Australia. A total of 1278 potential participants between the ages of 18 to 80 were selected at random from an electronic telephone directory. A trained telephone interviewer conducted a telephone survey using the Computer-Assisted Telephone Interviewing (CATI) program. RESULTS: A total of 822 participants completed the telephone interview. Six hundred three participants (73.4%) correctly identified the brain as the affected organ in stroke. The most common risk factors for stroke identified by respondents were smoking (identified by 324 [39.4%]) and stress (identified by 277 [33.7%]). The most common warning sign of stroke described by respondents was "blurred and double vision or loss of vision in an eye," listed by 198 (24.1%). A total of 626 (76.2%) respondents correctly listed >/=1 established stroke risk factor, but only 409 (49.8%) respondents correctly listed >/=1 warning sign. CONCLUSIONS: The level of knowledge in the community of established stroke risk factors, warning signs, and treatment as indicated by this survey suggests that a community-based education program to increase public knowledge of stroke may contribute to reducing the risk of stroke and to increasing the speed of hospital presentation after the onset of stroke.

The effect on blood lipids of eating charcoal-grilled meat.

For 9 days, 12 volunteers ate each day 8 oz of hamburgers and 6 oz of steak barbecued over charcoal. This was followed by a mean rise in high density lipoprotein (HDL) cholesterol of 25%. In addition there was a reduction in total cholesterol (the fall in total less the HDL fraction, which reflects mainly low density lipoprotein cholesterol was 20%). These changes were not seen when 6 of the subjects later ate the same quantity of meat under the same conditions except that it had been cooked in an electric oven. Benzo(a)pyrene and other polycyclic aromatic hydrocarbons have previously been shown to be produced in meat cooked over charcoal, and it is suggested that the resulting induction of the polycyclic hydrocarbon-dependent type of cytochrome P450 is responsible for inducing enzyme activity involved in lipid metabolism. Despite the beneficial effect that such changes in lipids might have on the risk of coronary heart disease, these findings should not be seen as a guide to long-term changes in cooking practice in view of the possible carcinogenic effects of benzo(a)pyrene produced in this way.

Coronary heart disease in 'low risk' men.

An attempt was made to explore the reasons why men develop coronary heart disease (CHD) despite being at low risk on the basis of established risk factors. A case control study was designed to take place after the end of a longitudinal study in which both low- and high-risk men who had developed CHD over the course of 5-6 years were compared with controls who had remained CHD-free, matched for initial risk characteristics. Low-risk men who had developed CHD had significantly lower levels of high density lipoprotein (HDL) cholesterol than their controls. This difference was not seen when high-risk men were compared with their controls. Apart from a suggestion that low risk cases had lower levels of free thyroxine (seen mainly when less severe categories of CHD were examined) there were no other significant differences between cases and controls (either low- or high-risk) in the other measured variables, which included levels of total testosterone and oestradiol in plasma, packed cell volume and heart rate. It is concluded that low levels of HDL cholesterol may partly explain why men who are otherwise at low risk develop CHD. This study design may be useful to test other hypotheses, particularly where it has not been possible to make the appropriate measurements at the start of a longitudinal study.

Secondary prevention after acute myocardial infarction.

The hypothesis that 6 months after acute myocardial infarction, adoption of secondary prevention activities would be higher, quality of life better, and blood cholesterol lower in patients randomly allocated to a mail-out intervention program than in those receiving usual care was tested. Patients were aged < 70 years, admitted to hospitals in and around Newcastle, Australia with a suspected heart attack and discharged alive from the hospital. Cluster randomization, based on the patient's family practitioner, was used to allocate consenting patients to an intervention or usual care group. A low-cost mail-out program was designed to help patients reduce dietary fat, obtain regular exercise by walking and (for smokers only) to quit smoking. Supplementary telephone contact was also used. In addition, a letter was sent to the family doctor regarding the benefit of aspirin and beta blockers for secondary prevention. Of eligible patients, 71% participated, and 79% of the 213 intervention subjects and 87% of the 237 usual care ones returned a 6-month follow-up questionnaire. Self-reported fat intake was significantly lower, an "emotional" score obtained from a quality-of-life questionnaire was significantly higher in the intervention than in the usual care group, and "physical" and "social" scores for quality of life were slightly higher. Blood cholesterol level and other variables were not different between the groups at 6 months. Simple low-cost programs providing support and advice on lifestyle change may be beneficial, particularly in improving patients' perceived quality of life.

Quality of life: an index for identifying high-risk cardiac patients.

A sample of 945 cardiac patients admitted under emergency conditions completed a quality of life questionnaire 4 months post-discharge. Half (471) were randomly allocated to a group used to develop a logistic regression model to predict mortality and cardiovascular morbidity 8 months later. Age 65-85 years, ever having heart failure, experiencing another cardiovascular event since discharge, and low global quality of life (QOL) score were found to be predictive of these outcomes; an interaction between QOL and heart failure was also found. The model was used to formulate a risk index which was validated in the remaining 474 patients. The index defines four levels of increasing risk of adverse outcomes, with rates in the development and validation groups, respectively, of: low risk 4% and 9%; moderate risk 13% and 15%; high risk 31% and 33%; very high risk 52% and 40%. Scores in the emotional, physical and social QOL domains were also found to be predictive of adverse outcomes, suggesting that interventions in any of these areas may prove beneficial. The index may be useful for follow-up evaluation of cardiac patients.

Accuracy of administrative data to assess comorbidity in patients with heart disease. an Australian perspective.

The objective of this study was to determine the accuracy of administrative data (by use of hospital discharge codes) for measuring comorbidity in patients with heart disease. One thousand seven hundred and sixty-five medical records of subjects admitted to hospital for AMI, unstable angina, angina pectoris, chronic IHD or heart failure were reviewed. The number and types of comorbidities were determined from the medical records (regarded as the "gold standard"). These were compared with the 10 discharge codes obtained from the hospital administrative records (referred to as the "administrative data"). The rate of false-negative and false-positive comorbidity diagnoses were determined. Twenty of the 21 comorbidities studied were underreported in the administrative data. For these 20 comorbidities, the median false-negative rate was 49.5% and ranged from 11% for diabetes to 100% for dementia. False-positive rates were low, less than 1.5%, except for chronic arrythmia (4.8%) and hypertension (4.2%). Mean percent agreement was high, ranging from 88% for hypertension to 100% for AIDS/HIV. Administrative data based on hospital discharge codes consistently underestimate the presence of comorbid conditions in our population. This has implications for administrators when estimating mortality, length of stay and disability. Researchers also need to be aware when using administrative data based on hospital discharge codes to assess subject's comorbidities that they may be widely underreported.

How soon after quitting smoking does risk of heart attack decline?

A population-based case-control study (involving 1282 cases and 2068 controls) was conducted to examine the risk of myocardial infarction or coronary death after cigarette smokers quit smoking. The odds ratios for current smokers were significantly elevated compared to non-smokers (OR = 2.7 for men and OR = 4.7 for women). For ex-smokers odds ratios declined rapidly after quitting and after about 3 years they were not significantly different from unity. Fibrinogen concentrations measured in the controls only were higher in current smokers and ex-smokers up to 2 years after quitting than in non-smokers and after that time were similar to levels in non-smokers; however, most of the differences among categories of smokers were not statistically significant. These results support the hypothesis that risk of a coronary event in ex-smokers declines rapidly after quitting and within 2-3 years is similar to the risk for non-smokers.

A prognostic index for 30-day mortality after stroke.

The objective of this study was to develop a simplified scoring system to predict 30-day mortality in patients with acute ischemic stroke. A retrospective cohort study was performed in a tertiary referral hospital in the Hunter Region of Australia. A prognostic index was created by assigning points to the variables in a Cox model. The index included impaired consciousness (5 points), dysphagia (3 points), urinary incontinence (4 points), admission body temperature higher than 36.5 degrees C (2 points), and hyperglycemia without a clinical history of diabetes (2 points). A score of 11 or more defined a high-risk group. The index achieved a sensitivity, specificity, and positive predictive value of 68%, 98% and 75%, respectively, in the derivation sample and 57%, 97% and 68%, respectively, in the validation sample. The results provide a simple risk stratification instrument for clinical research and practice. Further evaluation of the model in a prospective cohort is warranted

Where do developing World clinicians obtain evidence for practice: a case study on pneumonia.

There are few data on the practice of evidence based medicine in the developing world, nor on the actual sources of evidence that clinicians use in practice. To test the hypothesis that there was variation between and within developing countries in the proposed management of a patient with hospital acquired pneumonia, and that part of the variation can be explained by the sources of evidence used. Questionnaire responses to hypothetical case history. Investigators from 6 centres within the International Clinical Epidemiology Network (INCLEN) in China, Thailand, India, Egypt, and Kenya. Doctors chosen to represent primary and secondary hospital practice in the regions of the study centres. Investigations and initial treatments which would be ordered for a hypothetical 60-year-old woman who develops pneumonia 5 days after hospital admission, whether local data on antibiotic sensitivities are available and where information would be obtained to guide management. Chest x-ray and sputum gram stain/culture were consistently the most commonly ordered investigations, there being much greater variation in the initial treatment choices with either penicillin, a third-generation cephalosporin or aminoglycoside being the most popular choice. Textbooks were the commonest form of information source, and access to a library, textbooks and journals were statistically significantly associated with appropriate choice of investigations, but not treatment. Access to local antibiotic sensitivities was associated with appropriate initial treatment choice. Improving access to information in the literature and to local data may increase the practice of evidence-based medicine in the developing world.

A self-administered quality-of-life questionnaire after acute myocardial infarction.

A slightly modified version of the Quality-of-Life after Myocardial Infarction (QLMI) questionnaire developed by Oldridge and colleagues was applied in a self-administered mode to patients with suspected acute myocardial infarction (AMI) in a randomized controlled trial of secondary prevention. Acceptability of the questionnaire was good, with 93% of responders answering all items. Factor analysis suggested three quality-of-life (QL) dimensions which we called "emotional", "physical" and "social". These differed somewhat from the dimensions proposed by Oldridge and colleagues. However, a sensitivity analysis showed relative invariance of results to weighting schemes. Scores on our three dimensions were responsive to differences between the treatment groups, and demonstrated construct validity based on associations between the measured QL and variables expected to affect QL. We conclude that the QLMI questionnaire has good potential as an instrument for assessing QL in post-AMI patients and that it can be successfully self-administered.

Evaluation of a new course to teach the principles and clinical applications of epidemiology to medical students.

A new short course to teach clinical medical students the principles of epidemiology and their applications to clinical practice was introduced at St. Thomas's Hospital Medical School. During the first year one half of the students took the new course. All the students also received the previous epidemiological teaching which was performed on the wards in the context of individual patients with a particular disease. In the next year all students were given only the new course. One year after attending these courses, students completed a questionnaire designed to test how well the course objectives had been met. A comparison was made between those who had received the new course and those who had received only ward round teaching. Students exposed to both the ward rounds and the course were more satisfied with the latter and had a greater appreciation of the importance of epidemiology to clinical practice than students receiving only ward rounds. This improvement was maintained in the subsequent year when the ward rounds were dropped. Students who had the new course also performed relatively better than the others in the Community Medicine multiple choice questions in the Medicine Finals examination, and the marks improved in the subsequent year. This evaluation was also useful in identifying those aspects of the course that need further development.

Respiratory disease Mortality in Agricultural workers in eight member countries of the European community.

A co-operative study by representatives of eight member countries of the EEC into the problem of respiratory disease among agricultural workers is reported. From each country mortality data (routinely collected but often unpublished) were obtained for seven disease categories in the country as a whole, and separately where possible for urban and rural areas, and agricultural workers. The results indicate that comparable data can be collected from different countries despite variations in local methods of data collection and coding. There are large between country differences in respiratory disease mortality rates, and data for agricultural workers in France and England and Wales suggest an excess respiratory disease deaths (mainly pneumonia and influenza) among agricultural workers.

An evaluation of bruxism control: massed negative practice and automated relaxation training.

Behavior modification techniques of massed negative practice and relaxation training were applied to separate groups of individuals who had been diagnosed as "bruxers" by multiple criteria. When assessed by an objective index of grinding, neither technique was found to have reduced bruxism significantly. Grinding and state of anxiety scores of bruxers were significantly higher than those of nonbruxing controls. Bruxers did not differ from nonbruxers on trait anxiety measures.

Family history in "low risk" men with coronary heart disease.

A detailed family history was obtained from men who had earlier been participants in a longitudinal study of coronary heart disease (CHD). Men who developed CHD during the 5-6 years' course of that study were matched with those who had remained free of CHD, using age and initial risk characteristics (blood pressure, plasma cholesterol concentration, smoking habits, and physical activity at work) for the matching criteria. Men who developed CHD were more likely to report a family history of CHD than their controls, and the excess was greater in those who had been at low risk initially than in those at initially high risk. This suggests that a clue to the reason why men at low conventional risk develop CHD may lie in their family history, and that there may be an explanation other than the familial aggregation of conventional risk factors for CHD to run in families.

A population perspective to evidence based medicine: "evidence for population health".

We explore the notion that the public health community could learn lessons from the success of evidence based medicine (EBM) and develop a public health counterpart called "Evidence for Population Health". While EBM focuses on individual patients, its public health counterpart would aim to improve the health of communities effectively and efficiently.