Inpatient deaths from acute myocardial infarction, 1982-92: analysis of data in the Nottingham heart attack register

Rates and causes of death from non-ST elevation acute coronary syndromes: ten year follow-up of the PRAIS-UK registry

BACKGROUND

Long term nationally representative mortality rates following acute coronary syndrome (ACS) admissions are lacking beyond 5 years. We report rates and causes of mortality at approximately 10 years from PRAIS-UK.

METHODS

PRAIS-UK was a prospective registry of 1046 non-ST-elevation ACS admissions to 56 UK hospitals between 1998 and 1999. 493 patients surviving to 6 months were consented to long term follow-up. We identified deaths and causes (ICD codes) via the UK central death register and examined the influence of baseline characteristics and early revascularisation procedures. A modified GRACE risk score was constructed to determine the association of baseline score with long term risk of death.

RESULTS

The mean age was 66 years and 40% were women. After a median follow-up of 11.6 years (IQR 6.3-11.9), 46% (225) of patients had died with 55% being classified as cardiovascular. In a multivariate analysis, the following variables were associated with higher mortality (hazard ratio [HR] and 95% confidence intervals [CI]): age (10 years increase) 2.14 (1.87 to 2.45), ST depression or bundle branch block (compared to normal ECG) 1.68 (1.06 to 2.67), and history of heart failure (compared to no HF) 1.81 (1.28 to 2.56). The HR for risk of death in patients who received a revascularisation procedure (versus those who did not) in the first 6 months was 0.41 (0.24 to 0.69). The mean adapted GRACE score was 99.3 ± 26.4, associated with approximately 50% mortality at 10 years.

CONCLUSIONS

Non-ST elevation ACS is associated with about 50% mortality over 10 years that may be improved by early revascularisation. Well designed long-term registries can provide key data to determine prognosis and burden of disease.

Priority setting for research in health care: an application of value of information analysis to glycoprotein IIb/Illa antagonists in non-ST elevation acute coronary syndrome

The purpose of this study is to explain the rationale for the value of information approach to priority setting for research and to describe the methods intuitively for those familiar with basic decision analytical modeling. A policy-relevant case study is used to show the feasibility of the method and to illustrate the type of output that is generated and how these might be used to frame research recommendations. The case study relates to the use of glycoprotein Ilb/Illa antagonists for the treatment of patients with non-ST elevation acute coronary syndrome. This is an area that recently has been appraised by the National Institute for Health and Clinical Excellence.

'Lost in translation': accounting for between-country differences in the analysis of multinational cost-effectiveness data

Cost-effectiveness analysis has gained status over the last 15 years as an important tool for assisting resource allocation decisions in a budget-limited environment such as healthcare. Randomised (multicentre) multinational controlled trials are often the main vehicle for collecting primary patient-level information on resource use, cost and clinical effectiveness associated with alternative treatment strategies. However, trial-wide cost effectiveness results may not be directly applicable to any one of the countries that participate in a multinational trial, requiring some form of additional modelling to customise the results to the country of interest. This article proposes an algorithm to assist with the choice of the appropriate analytical strategy when facing the task of adapting the study results from one country to another. The algorithm considers different scenarios characterised by: (a) whether the country of interest participated in the trial; and (b) whether individual patient-level data (IPD) from the trial are available. The analytical options available range from the use of regression-based techniques to the application of decision-analytic models. Decision models are typically used when the evidence base is available exclusively in summary format whereas regression-based methods are used mainly when the country of interest actively recruited patients into the trial and there is access to IPD (or at least country-specific summary data). Whichever method is used to reflect between-country variability in cost-effectiveness data, it is important to be transparent regarding the assumptions made in the analysis and (where possible) assess their impact on the study results.

AIH versus prontuário médico no estudo do risco de óbito hospitalar no infarto agudo do miocárdio no Município do Rio de Janeiro, Brasil

O objetivo deste estudo é avaliar o desempenho do Sistema de Informações Hospitalares (SIH) em relação ao prontuário médico na análise dos fatores associados à variação do risco de óbito hospitalar no infarto agudo do miocárdio. O estudo envolveu uma amostra aleatória, estratificada por hospital, de 391 prontuários médicos sorteados com base nos 1.936 formulários de Autorização de Internação Hospitalar (AIH) registrados com o diagnóstico principal de infarto agudo do miocárdio no Município do Rio de Janeiro, Brasil, em 1997. Para estudo dos fatores associados à variação do risco de óbito hospitalar foram usados modelos logísticos a partir do SIH e do prontuário, com construção de curvas ROC para comparar desempenho relativo entre eles. O diagnóstico foi confirmado em 91,7% dos casos; a letalidade foi 20,6%. O modelo desenvolvido a partir do prontuário apresentou o melhor ajuste por incluir variáveis de gravidade e processo não disponíveis no SIH (concordância = 90,1%). O modelo derivado do SIH teve um menor poder explicativo (concordância = 70,6%), mas a correção de erros de digitação e informação através do prontuário não modificou significativamente seu desempenho. A maior limitação do SIH foi o elevado sub-registro do diagnóstico secundário.

Management of non-ST-elevation acute coronary syndromes: how cost-effective are glycoprotein IIb/IIIA antagonists in the UK National Health Service?

BACKGROUND

The glycoprotein IIb/IIIa antagonists (GPAs) represent a new class of drugs to prevent platelet aggregation in the acute treatment of non-ST-elevation acute coronary syndromes (NSTE-ACS). Systematic reviews have identified serious limitations in published cost-effectiveness analyses, including a lack of UK-specific studies and an absence of studies comparing different protocols for the use of GPAs.

METHODS

A model was developed to assess the cost effectiveness of a variety of protocols employing GPAs for patients presenting with NSTE-ACS in the UK. The perspective of the UK National Health Service was adopted, with outcomes in terms of quality-adjusted life-years (QALYs). Four treatment strategies were evaluated: GPAs as part of initial medical management (Strategy 1); GPAs in patients with planned percutaneous coronary interventions (PCIs; Strategy 2); GPAs as an adjunct to the PCI procedure (Strategy 3); and no GPAs (Strategy 4). Baseline event rates and costs were taken from a UK observational study of ACS patients and relative risk reductions from GPAs were taken from a meta analysis of trials. Long-term costs and QALYs were estimated using data from a UK longitudinal study.

RESULTS

The most cost-effective use of GPAs is likely to be Strategy 1, with an incremental cost per QALY gained of between pound4605 to pound10,343. Focusing this use of GPAs only on the subgroup of patients at high risk appears to represent the most cost-effective use of NHS resources.

CONCLUSIONS

Medical management of patients with NSTE-ACS using GPAs is the most cost-effective use of resources, particularly if targeted to higher risk subgroups.

Psychometric properties of a new health needs analysis tool designed for cardiac patients

BACKGROUND AND OBJECTIVES

Assessing health needs is pivotal in healthcare systems, ensuring that services are appropriate for a population's genuine needs. In the absence of an appropriate investigational tool, a comprehensive process of questionnaire development was undertaken to evaluate and validate a specific health needs assessment tool for cardiac patients (Nottingham Health Needs Assessment; NHNA). Its psychometric properties were investigated in a survey of patients admitted with acute coronary syndromes.

METHOD

Two hundred and forty-two consecutive patients admitted to an acute cardiac unit with symptoms suggestive of acute myocardial infarction completed a postal questionnaire about health needs and quality-of-life, using generic (Short Form 12 and EuroQol-5D) and specific (Seattle Angina Questionnaire) health-related quality-of-life instruments.

RESULTS

Forty-six items were assigned to five domains of health-related needs according to principal component analysis, with high internal consistency (0.83-0.89). Each domain in the NHNA questionnaire correlated highly with its quality-of-life counterpart, indicating relatively high concurrent validity.

CONCLUSION

The NHNA questionnaire has acceptable psychometric features, with satisfactory construct validity as determined by quality-of-life analysis. This health needs assessment instrument appears to be a reliable means of identifying patients' needs, which is an important landmark for directing health services.

Primary angioplasty should be first line treatment for acute myocardial infarction: AGAINST

The UK government is considering establishing a national primary angioplasty service for patients with acute myocardial infarction. David Smith and Kevin Channer debate whether moving away from first line thrombolysis is appropriate or practical

Missing, mediocre, or merely obsolete? An evaluation of UK data sources for coronary heart disease

STUDY OBJECTIVE

Coronary heart disease (CHD) is the commonest cause of death in the UK. However, there is no single comprehensive source of information to support CHD prevention and treatment strategies. Therefore this study evaluated the availability and quality of UK CHD data sources since 1981.

DESIGN

Data sources for England and Wales were identified and appraised on: (1) CHD patient numbers (myocardial infarction, angina, hypertension, and heart failure); (2) uptake of medical and surgical CHD treatments, and (3) population trends in major cardiovascular risk factors.

SETTING

England and Wales (population 53 million).

MAIN RESULTS

Population and mortality data were easily accessible from Office for National Statistics and British Heart Foundation Annual CHD Statistics; population based risk factor data came principally from the British Regional Heart Study, the General Household Survey, and the Health Survey for England. They were limited for 1981, but more extensive by 2000. Hospital admissions information since 1998 was available online from HES; but trend data and details of interventions were scant. Limited primary care data on consultation rates, prescribing, and treatment uptake were available from published audits and studies.

CONCLUSIONS

Information on CHD in the UK is fragmented, patchy, and mixed in quality. Data for women, the elderly populatiom, and ethnic minorities were particularly scarce, exacerbating inequalities. Future CHD disease monitoring and evaluation will require comprehensive and accurate population based information on trends in patient numbers, treatment uptake, and risk factors.

The development of a simulation model of the treatment of coronary heart disease

A discrete event simulation models the progress of patients who have had a coronary event, through their treatment pathways and subsequent coronary events. The main risk factors in the model are age, sex, history of previous events and the extent of the coronary vessel disease. The model parameters are based on data collected from epidemiological studies of incidence and prognosis, efficacy studies. national surveys and treatment audits. The simulation results were validated against different sources of data. The initial results show that increasing revascularisation has considerable implications for resource use but has little impact on patient mortality.

Size isn't everything

Clinical trials now often involve thousands of patients, and statisticians emphasize the importance of trial size in ensuring that 'correct' answers are obtained. However, when a good treatment appears for a disease that was hitherto untreatable - for example, oranges for scurvy or streptomycin for tuberculosis - only a small trial is needed. Large trials are only needed to demonstrate small effects. The meta-analysis of small trials is often misleading, and may hide undesirable effects of individual drugs. The concept of equivalence between treatments is important, and while a statistically adequate equivalence trial may have to be very large, many clinicians will question the need for extreme statistical propriety. Clinical trials often do not reflect 'real world' practice, and the clinical relevance of a trial is more important than its size.

Changing the diagnostic criteria for myocardial infarction in patients with a suspected heart attack affects the measurement of 30 day mortality but not long term survival

OBJECTIVES

To explore the effects of alternative methods of defining myocardial infarction on the numbers and survival patterns of patients identified as having sustained a confirmed myocardial infarct.

DESIGN

An inclusive historical cohort of patients admitted with a suspected heart attack. Patients were recoded from raw clinical data (collected at the index admission) to the epidemiological definitions of myocardial infarction used by the Nottingham heart attack register (NHAR), the World Health Organization (MONICA), and the UK heart attack study.

SETTING

Single health district.

PATIENTS

The NHAR identified all patients admitted in 1992 with suspected myocardial infarction.

OUTCOME MEASURES

Survival at 30 days and four year postdischarge.

RESULTS

2739 patients were identified, of whom 90% survived to discharge. Recoding increased the numbers of patients defined as having confirmed myocardial infarction from 26% under the original NHAR classification to 69%, depending on the classification system used. In confirmed myocardial infarction, subsequent 30 day survival from admission varied from 77-86% depending on the classification system; four year survival after discharge was not affected. The distribution of important prognostic variables differed significantly between groups of patients with confirmed myocardial infarction defined by different systems. Patients with suspected but unconfirmed myocardial infarction under all classification systems had a worse postdischarge mortality.

CONCLUSIONS

The classification system used had a substantial effect on the numbers of patients identified as having had a myocardial infarct, and on the 30 day survival. There were significant numbers of patients with more atypical presentations, not labelled as myocardial infarction, who did badly following discharge. More research is needed on these patients.

Pharmacological management of acute myocardial infarction in the municipal district of Rio de Janeiro

CONTEXT

International studies have shown a large variation in the utilization patterns of interventions, in acute myocardial infarction.

OBJECTIVE

To analyze utilization patterns of pharmacological interventions in acute myocardial infarction and their corresponding effects on hospital mortality.

DESIGN

Cross-sectional study. LOCAL: Hospitals of the Brazilian National Health System (SUS) in the municipal district of Rio de Janeiro.

SAMPLE

A stratified hospital sample of 391 medical records selected from the 1,936 admissions registered in the SUS Hospital Information System (SIH/SUS) with a main diagnosis of acute myocardial infarction, in the studied district in 1997.

MAIN MEASUREMENTS

Sex, age, time to treatment, risk factors, severity factors, diagnosis confirmation, use of pharmacological interventions, hospital death, contraindication of the use of thrombolytic therapy, contraindication of aspirin use.

RESULTS

We reviewed 98.2% of the sampled medical records. Acute myocardial infarction diagnosis was confirmed in 91.7% (95% CI 88.3 to 94.2). 61.5% were men and 38.5% women, with an average age of 60.2 years (SD 2.4). The median time interval between symptom onset and hospital admission was 11 hours. Hospital mortality was 20.6% (95% CI 16.7 to 25.0). Intravenous thrombolytic therapy was used in 19.5% (95% CI 15.8 to 23.9) of the cases; aspirin in 86.5% (95% CI 82.5 to 89.6); beta-blockers in 49.0% (95% CI 43.8 to 54.1); angiotensin-converting enzyme (ACE) inhibitors in 63.3% (95% CI 58.2 to 68.1); nitrates in 82.0% (95% CI 82.4 to 89.6); heparin in 81.3% (95% CI 76.9 to 85.0); calcium antagonists in 30.5% (95% CI 26.0 to 35.4). There was a significant variation in the use of thrombolytic therapy, beta-blockers, ACE inhibitors, calcium antagonists and heparin among hospitals of different juridical nature.

CONCLUSIONS

There was underutilization of some interventions with well-established efficacy (thrombolytic therapy, aspirin, beta-blockers and intravenous nitrates). The use of calcium antagonists, not supported by scientific evidence in acute myocardial infarction, was quite frequent. A logistic model documented the benefit of aspirin, beta-blockers and ACE inhibitor use in reducing the chance of hospital death.

Age, sex, and social trends in out-of-hospital cardiac deaths in Scotland 1986-95: a retrospective cohort study

BACKGROUND

Most deaths from coronary heart disease occur out of hospital. Hospital patients face social, age, and sex inequalities. Our aim was to examine inequalities and trends in out-of-hospital cardiac deaths.

METHODS

We used the Scottish record linked database to identify all deaths from acute myocardial infarction that occurred in Scotland (population 5.1 million), in 1986-95. We have compared population-based death rates for men and women across age and social groups.

FINDINGS

Between 1986 and 1995, 83365 people died from acute myocardial infarction, out of hospital and without previous hospital admission (44655 men, 38710 women); and 117749 were admitted with a first acute myocardial infarction, of whom 37020 died within 1 year. Thus, out-of-hospital deaths accounted for 69.2% (95% CI 69.0-69.5) of all 120385 deaths. Out-of-hospital deaths, measured as a proportion of all acute myocardial infarction events (deaths plus first hospital admissions), increased with age, from 20.1% (19.2-21.0) in people younger than 55 years, to 62.1% (61.3-62.9) in those older than 85 years. Population-based out-of-hospital mortality rates fell by a third in men and by a quarter in women. Mean yearly falls were larger in people aged 55-64 years (5.6% per year in men, 3.7% in women), than in those older than 85 years (2.5% in men and women). Mortality rates were substantially higher in deprived socioeconomic groups than in affluent groups, especially in people younger than 65 years.

INTERPRETATION

These inequalities in age, sex, and socioeconomic class should be actively addressed by prevention strategies for coronary heart disease.

[Characteristics of acute myocardial infarction patients treated with mechanical ventilation. Data from the ARIAM Registry]

INTRODUCTION

Scarce information is available about the use, clinical course and follow-up of patients with acute myocardial infarction treated with mechanical ventilation.

PATIENTS AND METHOD

Historical cohort study of patients with acute myocardial infarction, included in Spanish registry ARIAM. Differences in clinical characteristics and prognosis from patients treated with or without mechanical ventilation were compared.

RESULTS

Three hundred and thirty-three of the 4143 patients (8.1%) with acute myocardial infarction were treated with mechanical ventilation. Treated patients were older, more frequently female, and had more frequently reinfarcts, anterior infarction, Killip III and IV, and higher creatine phosphokinase peak. Diabetes and high blood pressure were more frequent in those in which the technique was applied. They had a higher mortality at the coronary care unit (65.7 vs 5.1%; p < 0.001) than the non-ventilated patients. In multivariate analysis, creatine phosphokinase peak levels higher than 1.200 units/ml, Killip III and IV, and an infarction localization different to inferior were independent predictors of mechanical ventilation application. The 220 treated patients who died were older, more frequently female, had been more frequently admitted to the coronary unit, and had Killip IV whereas Killip III was more frequent among survivors. In multivariate analysis, restricted to patients treated with mechanical ventilation, Killip III was an independent predictor of survival with an odds ratio for mortality of 0.26 (CI 95%: 0.09-0.77).

CONCLUSIONS

Mechanical ventilation is a vital support technique employed in a significant number of complicated acute myocardial infarction patients. The high mortality of these patients was related to more extended myocardial infarction and a worse clinical state.

Prognostic implications of ventricular fibrillation in acute myocardial infarction: new strategies required for further mortality reduction

OBJECTIVE

To determine the changing risk of ventricular fibrillation, the prognostic implications, and the potential long term prognostic benefit of earlier hospital admission, after acute myocardial infarction.

DESIGN

Prospective observational study.

SETTING

A district general hospital in east London.

PATIENTS

1225 consecutive patients admitted to a coronary care unit with acute myocardial infarction.

MAIN OUTCOME MEASURES

Time of onset of pain and ventricular fibrillation, and long term survival of patients admitted with acute myocardial infarction.

RESULTS

The rate of ventricular fibrillation in these hospital inpatients was high in the first hour from onset of pain (118 events/1000 persons/h; 95% confidence interval (CI) 50.7 to 231) and fell rapidly to an almost constant low level by six hours; 27.4% of patients with early ventricular fibrillation died in hospital, compared with 11.6% of those without (p < 0.0001), but mortality in patients who survived to hospital discharge was not altered by early ventricular fibrillation (five year survival: 75.0% (95% CI 60.0% to 84.8%) with ventricular fibrillation v 73.3% (95% CI 69.6% to 76.6%) without ventricular fibrillation).

CONCLUSIONS

Patients successfully resuscitated from early ventricular fibrillation have the same prognosis as those without ventricular fibrillation after acute myocardial infarction. Faster access to facilities for resuscitation must be achieved if major improvements in the persistently high case fatality of patients after acute myocardial infarction are to be made.

Attack rate, mortality and case fatality for acute myocardial infarction in Sweden during 1987-95. Results from the national AMI register in Sweden

OBJECTIVE

To assess trends in attack rate, mortality and case-fatality of acute myocardial infarction (AMI) in Sweden.

SETTING

All 303 324 Swedes discharged from hospitals, or deceased, with a diagnosis of AMI between 1987 and 1995.

DESIGN

Analysis based on the National AMI Register in Sweden. The National AMI Register was assembled by linking the records of the National Hospital Discharge Register and the National Cause of Death Register in Sweden.

MAIN OUTCOME MEASURES

Age-standardized attack rate, mortality and case fatality rates for AMI.

RESULTS

Between 1987 and 1995, the age-standardized attack rate of AMI declined by 11% for men and 10% for women, whilst mortality from AMI decreased by 14% for both sexes. The decrease was most pronounced for men below the age of 64, with a reduction of 22% in attack rate and nearly 30% in mortality. There was no change over time in the case fatality rates on the date of attack, including also deaths outside hospital, whilst case fatality within 28 days decreased from 49 to 45% amongst men, and 45 to 42% amongst women. This reduction persisted over 1 year of follow-up.

CONCLUSIONS

The decrease in attack rate of AMI in Sweden may be attributed both to changes in risk factors amongst the population and to improved medical intervention. The decline in case fatality rates indicates that improved treatment of patients with AMI has contributed to the reduction in mortality. However, the high, and essentially unchanged, proportion of deaths outside hospital stresses the importance of disease prevention.

Regional variation in incidence and case fatality of myocardial infarction among young women in England, Scotland and Wales

OBJECTIVES

To examine the regional variation in incidence and case fatality of myocardial infarction among young women.

DESIGN

Cross sectional survey, using population based incidence data.

SETTING

England, Scotland and Wales.

SUBJECTS

Subjects were women aged 16-44 with a diagnosis of myocardial infarction between 1 October 1993 and 15 October 1995.

OUTCOME MEASURES

Incidence of myocardial infarction per 100,000 women years, with case fatality as a percentage of total cases.

RESULTS

Incidence of myocardial infarction rose steeply from age 33 upwards, (maximum = 20.2 cases per 100,000 women years at age 44). The adjusted incidence rate for myocardial infarction was 3.7 (95% CI 3.2, 4.2) times greater in Scotland than in southern England. In contrast, case fatality was significantly lower in Scotland: 18.5% (95% CI 13.1%, 25.0%), compared with 31.0% (95% CI 25.9%, 36.0%) in southern England.

CONCLUSIONS

The incidence of myocardial infarction varied widely within the United Kingdom. Case fatality variation may reflect differences in ambulance response, or in diagnostic acumen, within the regions.

Temporal changes in the outcomes of acute myocardial infarction in Ontario, 1992-1996

BACKGROUND

There is relatively little information available on recent population-based trends in the outcomes of patients who have had an acute myocardial infarction (AMI). We, therefore, conducted a study of temporal trends in the outcomes of AMI patients in Ontario, Canada, between the 1992 and 1996 fiscal years.

METHODS

114,618 AMI patients were discharged from hospitals in Ontario between Apr. 1, 1992, and Mar. 31, 1997. After specific exclusion criteria were applied the final sample of 89,456 patients was divided into 5 cohorts according to the fiscal year of discharge. As part of the Ontario Myocardial Infarction Database project the linked administrative data pertaining to these patients were used to examine cohort characteristics, cardiac procedures used and mortality rates for each of the 5 cohorts over time.

RESULTS

There was a significant increase in the percentage of patients in Ontario receiving coronary angiography, percutaneous transluminal coronary angioplasty and coronary artery bypass grafting surgery (p < 0.001) after an AMI between 1992 and 1996. In addition, the overall 30-day risk-adjusted mortality rate declined from 15.5% in 1992 to 14.0% in 1996 (p = 0.001) and the 1-year risk-adjusted mortality rate declined from 23.7% in 1992 to 22.3% in 1996 (p = 0.017). Virtually all of the improvement occurred within 30 days of admission. The absolute decline in 1-year mortality rates was significant for patients under the age of 65 (2.3%, 95% confidence interval [CI] 1.4% to 3.2%) and for males (1.2%, 95% CI 0.2% to 2.2%); absolute declines were not significant for patients 65 years of age or older (0.7%, 95% CI -0.6% to 2.0%) and for female patients (-0.1%, 95% CI -1.7% to 1.5%). Interestingly, post-infarction coronary angiography and coronary artery bypass grafting rates were consistently lower in the older and the female patients throughout the study period.

INTERPRETATION

There was a modest improvement in the short- and long-term survival of patients in Ontario after an AMI between 1992 and 1996. The Ontario experience suggests that recent advances in AMI management have been of more benefit to younger and male AMI patients.

Review of Emergency Department thrombolytic therapy and changes in inpatient mortality of acute myocardial infarction on the NSW Central Coast 1986 to 1994-96

AIMS

To examine changes in inpatient mortality of acute myocardial infarction (AMI) from 1986 to 1994-96 and to review the Emergency Department (ED) use of thrombolytic therapy (TT) for AMI on the NSW Central Coast.

METHOD

A retrospective review of medical records of patients presenting to the EDs of Gosford and Wyong Hospitals with a discharge diagnosis of AMI (ICD9 code 410.x) from 1 January 1986 to 31 December 1986 and 1 January 1994 to 31 December 1996. Data were collected on patients' age, sex, duration of symptoms on arrival at the ED, ECG changes and presence of positive ECG criteria for thrombolysis, agent used, contraindications to TT, and inpatient mortality. The main measure of outcome was inpatient mortality.

RESULTS

There were 423 admissions for AMI in 1986 and 1,220 admissions in 1994-96. The overall inpatient mortality has declined from 18.9% in 1986 to 9% in 1994-96 (p<0.0001). The mean age of patients has increased from 67.5 years to 68.1 years (p=0.35). The proportion of patients over age 75 years has increased significantly from 24.6% to 30.3% (p<0.0001). Presentation times from onset of symptoms have not changed significantly from a median time of two hours in 1986 to 2.5 hours in 1994 to 1996 (p=0.52). The overall proportion of patients with ECG criteria for TT was 53.2% in 1994-96. TT was administered to 42.9% of patients with a mean door to needle time of 67 minutes (median 45 minutes). The Australasian College for Emergency Medicine benchmark door to needle time of 60 minutes was achieved in 71.3% of patients. Streptokinase was the predominant agent given in 78%, while recombinant tissue plasminogen activator accounted for 15.7% of patients. Patients not receiving TT due to negative ECG criteria showed a decline in mortality from 18.6% to 6.7% (p<0.0001). Patients who underwent mechanical revascularisation (by bypass graft or angioplasty) increased from 8.7% to 17.4% (p<0.0001). Inpatient mortality has declined for all age groups, for both sexes, and for all sites of AMI.

CONCLUSION

There have been significant declines in inpatient mortality of patients with AMI on the Central Coast. TT has had a significant impact on this decline but has an eligibility rate of less than half. Significant declines in mortality have also been seen in patients ineligible for thrombolysis. These patients have benefited from other therapies introduced or more widely used in the last decade. The results achieved on the Central Coast compare favourably with published reviews in Australia and overseas despite the lack of facilities for coronary angiography, coronary angioplasty and cardiothoracic surgery.

Hospital mortality from acute myocardial infarction has been modestly reduced after introduction of thrombolytics and aspirin: results from a new analytical approach. European Secondary Prevention Study Group

The objective of this study was to investigate how the introduction of thrombolytics and aspirin has affected hospital mortality (case fatality) among patients with acute myocardial infarction. The study design was the application of the therapeutic effects found in the clinical trials in a nonselected myocardial infarction population characterized in detail. The study took place in health region 1 in Norway, population 850,000, and subjects were all patients hospitalized and discharged, alive or dead, with a diagnosis of acute myocardial infarction in the 10 hospitals in the region over a period of 2 months. The main outcome measures were deaths in hospital and estimation of expected hospital mortality without thrombolytics or aspirin, weighing and evaluating the effects of delay of different lengths from onset of symptoms to admission, different ages, and different electrocardiogram changes. We found that 32% of the patients received thrombolytics, and 72% received aspirin. Hospital mortality was 18.1% compared with 20.6% had neither of the treatments been administered, implying that the two regimens had reduced mortality by 12%, aspirin contributing about four fifths and thrombolytics one fifth. We conclude that hospital mortality in a nonselected myocardial infarction population has been reduced to moderate extent since the introduction of thrombolytics and aspirin. The effects observed in clinical trials are not translated into epidemiologically documented reduction in mortality, as the optimal conditions are found only in a proportion of the patient groups constituting a nonselected myocardial infarction population.

Relevance of clinical trial results in myocardial infarction to medical practice: comparison of four year outcome in participants of a thrombolytic trial, patients receiving routine thrombolysis, and those deemed ineligible for thrombolysis

OBJECTIVE

To assess the medium to long term outcome of patients ineligible for thrombolysis compared to those enrolled in a clinical trial of thrombolysis and patients receiving non-trial thrombolysis.

DESIGN

Cohort study based on the Nottingham heart attack register.

SETTING

Two district general hospitals serving a defined urban/rural population.

SUBJECTS

All patients admitted with a confirmed acute myocardial infarction during 1992 categorised as either participants of a thrombolytic trial (group A, n = 140), receiving non-trial thrombolysis (group B, n = 329), or deemed ineligible for lytic treatment (group C, n = 431).

MAIN OUTCOME MEASURES

Background characteristics, inhospital treatment, patterns of follow up, referrals to cardiologists, revascularisation rates, and short and long term survival.

RESULTS

Clinical trial recruits were younger by almost 10 years, were less likely to have a previous history of myocardial infarction, and more likely to be in Killip class 1 on admission than those ineligible for thrombolysis. Cardiology follow up was mandatory for all surviving trial participants but 22% of patients in group B and 31% of patients in group C received no follow up, and during four years less than 50% ever saw a cardiologist. Revascularisation was performed in 17.2% of patients in group A, 13.6% of patients in group B, and 7.5% of patients in group C. Cumulative mortality at a median of four years was 24.3% in group A, 36.8% in B, and 59.6% in group C. Adjusting for age, sex, previous myocardial infarction, type of infarction, and Killip class in a logistic regression model the odds ratios (OR) of death at four years for groups B and C were 1.60 (95% confidence intervals (CI) 0.97 to 2.63, p = 0.065) and 2.64 (95% CI 1.61 to 4. 32, p < 0.001), respectively, when compared to group A (OR 1).

CONCLUSIONS

Patients enrolled into thrombolytic trials are at low risk. Patients deemed ineligible for thrombolysis are high risk, receive less surveillance, are less likely to be revascularised or receive trial proven treatments, have a poor long term outcome not entirely explained by increased age or severity of infarction, and deserve further evaluation.

Hospital mortality of acute myocardial infarction in the thrombolytic era

OBJECTIVE

To examine the management and outcome of an unselected consecutive series of patients admitted with acute myocardial infarction to a tertiary referral centre.

DESIGN

A historical cohort study over a three year period (1992-94) of consecutive unselected admissions with acute myocardial infarction identified using the HIPE (hospital inpatient enquiry) database and validated according to MONICA criteria for definite or probable acute myocardial infarction.

SETTING

University teaching hospital and cardiac tertiary referral centre.

RESULTS

1059 patients were included. Mean age was 67 years; 60% were male and 40% female. Rates of coronary care unit (CCU) admission, thrombolysis, and predischarge angiography were 70%, 28%, and 32%, respectively. Overall in-hospital mortality was 18%. Independent predictors of hospital mortality by multivariate analysis were age, left ventricular failure, ventricular arrhythmias, cardiogenic shock, management outside CCU, and reinfarction. Hospital mortality in a small cohort from a non-tertiary referral centre was 14%, a difference largely explained by the lower mean age of these patients (64 years). Five year survival in the cohort was 50%. Only age and left ventricular failure were independent predictors of mortality at follow up.

CONCLUSIONS

In unselected consecutive patients the hospital mortality of acute myocardial infarction remains high (18%). Age and the occurrence of left ventricular failure are major determinants of short and long term mortality after acute myocardial infarction.

Relationship of therapeutic improvements and 28-day case fatality in patients hospitalized with acute myocardial infarction between 1978 and 1993 in the REGICOR study, Gerona, Spain. The REGICOR Investigators

BACKGROUND

The aim of this study was to analyze 28-day case fatality trends between 1978 and 1993 among hospitalized acute myocardial infarction (AMI) patients in the REGICOR registry, Gerona, Spain, and relate them to thrombolytic and antiplatelet drug use and changes in patient characteristics.

METHODS AND RESULTS

A total of 2053 consecutive patients 25 to 74 years of age with a first Q-wave AMI admitted to the reference hospital between 1978 and 1993 were registered. Clinical characteristics and patient management were recorded. Four 4-year periods were considered: 1978 to 1981, 1982 to 1985 (prethrombolytic therapy), 1986 to 1989 (thrombolytic and antiplatelet drugs introduced), and 1990 to 1993 (thrombolytic and antiplatelet drugs used routinely). The end point was death at 28 days. Case fatality at 28 days decreased 6% per year between 1978 and 1993. A logistic model adjusted for comorbidity and severity showed the last 3 periods to present a steep decrease in the OR of death at 28 days: 0.86 (95% CI, 0.52 to 1.41), 0.59 (95% CI, 0.35 to 0.99), and 0.40 (95% CI, 0.24 to 0.69), respectively, compared with the first period. After 1986, 85.7% of the 112 lives saved could be attributed to the use of antiplatelet and thrombolytic drugs. Adjusted relative risk reduction was 56.0% for antiplatelet drugs, 34.1% for thrombolytic drugs, and 77.9% for the 2 combined.

CONCLUSIONS

Our results strongly suggest that new therapies introduced since 1986 have contributed to the decrease in 28-day case fatality of patients admitted with a first Q-wave AMI. This decrease could be attributable mainly to the use of antiplatelet and thrombolytic drugs. These findings should encourage the routine use of thrombolytic and antiplatelet drugs and particularly their combination in the acute phase of AMI.

Achieving appropriate endpoints in heart failure trials: the PRIME-II protocol. The Second Perspective Randomised study of Ibopamine on Mortality and Efficacy

Many clinical trials unintentionally include patients with a low risk of the trial endpoints. PRIME II (The Second Perspective Randomised study of Ibopamine on Mortality and Efficacy) was a large international randomised double blind trial comparing the addition of ibopamine or placebo to the therapy of patients with advanced heart failure. The trial was stopped prematurely because ibopamine was associated with an increased fatality rate, but the protocol achieved its objective of including high-risk patients. Here we describe the protocol details that enabled patients with the desired degree of risk to be included. We also amplify our definition of mode of death. The PRIME II protocol was designed with the intention that patients in the placebo group would have an annual fatality rate of 20%. Since the study was to be conducted in some 200 centres in 13 European countries, the inclusion criteria had to be simple and flexible, allowing for different clinical practice. The inclusion criteria, together with the use of simple investigations (which did not have to include angiographic or radionuclide ventriculography) are described. The annual fatality rate in the placebo group was just over 20%. Six categories of mode of death were used, but while they were reasonably easy to apply they did not reveal the reason for the unexpected adverse effect of ibopamine. The inclusion and exclusion criteria used for PRIME II, and the definitions of mode of death, were effective. The PRIME II protocol can be used as a model for future heart failure studies.

Shortcomings of the randomized controlled trial: a view from the boondocks

The randomized controlled trial (RCT), despite its well-known limitations, continues to be regarded as a gold standard in determining whether an intervention does more harm than good. Some recent evidence suggests that it tends to overvalue the modalities it tests. Moreover, the accuracy with which the disorder under consideration is diagnosed can be critical to the performance of a new intervention designed for it. When technological progress allows us to diagnose milder instances, some therapies, possibly useful in dire circumstances, will appear ineffective if most of a trial population is at low risk. Human individuality makes it impossible to duplicate a RCT. As a result, Popper's criterion of falsifiability may not be met and so the carrying out of a large-scale therapeutic experiment may not be a scientific activity. Finally, it is doubtful whether group probabilities derived from RCTs can be safely applied to individuals. These and other reservations concerning the applicability of the RCT to clinical practice are discussed.

Coronary event and case fatality rates in an English population: results of the Oxford myocardial infarction incidence study. The Oxford Myocardial Infarction Incidence Study Group

OBJECTIVES

To determine coronary event and case fatality rates in an English population aged less than 80 years in Oxfordshire, and to compare these rates with those reported by the UK monitoring trends and determinants of cardiovascular disease (MONICA) centres in Scotland and Northern Ireland and those ascertained in Oxfordshire in 1966-67.

DESIGN

A population wide surveillance study conducted in 1994-95 using prospective and retrospective case ascertainment.

SETTING

A resident population in Oxfordshire of 568,800.

SUBJECTS

Patients with suspected myocardial infarction or coronary death.

OUTCOME MEASURES

A diagnosis of definite or possible myocardial infarction or coronary death using WHO MONICA diagnostic criteria based on symptoms, electrocardiograms, cardiac enzymes, necropsy findings, and past medical history.

RESULTS

The annual rate for a first or recurrent coronary event per 100,000 population aged less than 65 years in 1994-95 was 273 for men and 66 for women after age adjustment to a standard world population. Rates in the age group 65-79 years were 1350 for men and 677 for women. Between 1966-67 and 1994-95, the age standardised event rate in the age group 30-69 years decreased significantly by 33% (95% confidence interval (CI) 44 to 21) in men, and there was a non-significant reduction of 8% (95% CI -33 to 17) in women. The age standardised 28 day case fatality rates also decreased significantly by 28% (95% CI 41 to 15) in men and by 32% (95% CI 55 to 9) in women.

CONCLUSIONS

The coronary event rate in Oxfordshire was much lower than rates reported by MONICA centres in Glasgow and Belfast, and similar to rates reported by MONICA centres in France and northern Italy. The substantially lower event rate accounts for lower coronary heart disease mortality in Oxfordshire than in Scotland and Northern Ireland. The reduced coronary mortality in this region is attributable to declines in coronary event and case fatality rates.