Declining trend in mortality after myocardial infarction

Predicting long-term mortality after a myocardial infarction from routine hospital data

Among 528 patients under 67 years of age discharged alive after a myocardial infarction (MI), the cumulative survival rates after 3, 5, and 7 years were 84.1%, 75.9% and 68.6%, respectively. Compared with the "normal" population, the relative mortality risk was 4.8 for the first year, 3.1 for the second, and on average 2.1 for the next 5 years. Significant age differences were not observed for relative mortality. A multivariate Cox proportional hazards model showed long-term mortality to be independently related to higher age, a reduced working activity before the MI, previous cardiovascular disease, and a higher inhospital complication score, which was computed by summing eight defined clinical events weighted for severity. The results indicate that a reasonable prediction of long-term survival after a MI can be made from routine hospital data.

Exploring sex differences in case fatality in acute myocardial infarction or coronary death events in the northern Sweden MONICA Project

OBJECTIVES

To investigate sex differences in reaching diagnosis, medical management and case fatality (CF) in acute myocardial infarction (AMI) in the population aged 35-64 years in northern Sweden.

METHODS

Within the framework of the World Health Organization Multinational Monitoring of Trends and Determinants in Cardiovascular Diseases (MONICA) Project, definite AMI was monitored in people aged 35-64 years from 1989 through 1995 (target population 510 000 in 1991).

SETTING

In a population based coronary register, all coronary events were recorded in nine hospitals in 1989-95.

RESULTS

The number of events included in the definite coronary myocardial infarction register was 2483 men and 669 women. On admission, a higher proportion of men with definite AMI had chest pain or ECG changes typical for AMI (P < 0.0001). Disagreement between clinical diagnosis and classification by MONICA criteria occurred more often in women (P=0.008). A significantly higher proportion of men was admitted in the coronary care unit and they were significantly more often treated with thrombolytics, nitroglycerine, beta-blockers, or antiplatelet agents. Women received significantly more diuretics, inotropics or calcium antagonists. Diabetes, conferring a worse prognosis, was more common in women (20 vs. 15%; P=0.003). Prehospital CF was significantly higher in men (24.1 vs. 18.3%; P=0.005), but in patients treated in hospital, the CF was significantly lower in men (12.7 vs. 21.2%; P < 0.001). Total CF was equal in men and women.

CONCLUSIONS

Several factors contributing to the excess in-hospital CF in women were identified, including greater problems in diagnosis of AMI in women which may be one of the reasons for less intensive treatment in women. Differences in co-morbidity, most notably diabetes and medical treatment between men and women with acute AMI may also have played a part.

Marked improvement in survival after acute myocardial infarction in middle-aged men but not in women. The Northern Sweden MONICA study 1985-94

OBJECTIVES

The aim of this study was to analyse time trends in survival after acute myocardial infarction with special emphasis on sex differences.

DESIGN

Within the framework of the population-based WHO MONICA Project, all acute myocardial infarction events were recorded in the age group 25-64 years in northern Sweden during the period 1985-94. All first-ever myocardial infarction patients were followed for information on vital status.

SUBJECTS

A total of 3397 men and 860 women with acute myocardial infarction, during the period between 1985 and 1994.

MAIN OUTCOME MEASURES

Case fatality rates after first-ever acute myocardial infarction.

RESULTS

When compared with the 1985-86 cohort, the age-adjusted odds ratio for death within 1 year after acute myocardial infarction was 0.59 (95% CI 0.46-0.76) in the 1993-94 male cohort but 0.99 (95% CI 0.61-1.60) in the female 1993-94 cohort. Corresponding age-adjusted proportions of death within 1 year were 33.3% and 22.9% in men and 27.5% and 27.3% in women in 1985-86 and 1993-94, respectively. The odds ratio for 3-year case fatality amongst those who survived the first 28 days was 0.34 (95% CI 0.21-0.55) in 1991-92 compared with 1985-86 in men and 0.91 (0.43-1.94) in women.

CONCLUSION

Both short- and long-term survival after AMI have improved markedly in men over the last decade. There is a disturbing sex difference in that, during the same period, survival in women with AMI has not improved at all. This sex difference was not explained by differences in conventional prognostic factors.

Enhanced thrombolytic and antithrombotic potency of a fibrin-targeted plasminogen activator in baboons

BACKGROUND

Thrombolytic therapy reduces mortality in patients with acute myocardial infarction, but significant limitations exist with the use of currently available agents. In the present report, we describe the thrombolytic and antithrombotic potencies of a hybrid recombinant plasminogen activator consisting of an antifibrin antibody 59D8 (AFA) and low-molecular-weight single-chain urokinase-type plasminogen activator (scuPA).

METHODS AND RESULTS

A thrombolysis model in which thrombi are preformed in vivo in juvenile baboons was developed to compare the potencies of AFA-scuPA, recombinant tissue plasminogen activator (rTPA), and recombinant scuPA (rscuPA) in lysing nonocclusive 111In-labeled platelet-rich arterial-type thrombi and 125I-labeled fibrin-rich venous-type thrombi. Systemic infusion of 1.89 nmol/kg AFA-scuPA produced thrombolysis that was comparable to that obtained with much higher doses of TPA (14.2 nmol/kg) and rscuPA (28.5 nmol/kg). When steady-state plasma concentrations are normalized, AFA-scuPA lyses thrombi sixfold more rapidly than scuPA and TPA (P < .001) and reduces the rate of formation more than comparable doses of rscuPA (P < .0001). At equivalent thrombolytic doses, AFA-scuPA produced fewer antihemostatic effects than either rTPA or rscuPA. Template bleeding time measurements were shorter (3.5 +/- 0.12 minutes for AFA-scuPA versus 5.3 +/- 0.36 and 5.2 +/- 0.04 minutes for rTPA and rscuPA, respectively; P < .05), alpha 2-antiplasmin consumption was less (P < .05), and D-dimer generation was lower (P < .05).

CONCLUSIONS

We conclude that antibody targeting of scuPA to fibrin increases thrombolytic and antithrombotic potencies with less impairment of hemostasis compared with rTPA and rscuPA.

Population-wide mortality trends among patients hospitalized for acute myocardial infarction: the Ontario experience, 1981 to 1991

OBJECTIVES

This study attempted to determine population-based trends in in-hospital patient fatality from acute myocardial infarction.

BACKGROUND

The in-hospital prognosis for patients with acute myocardial infarction should be improving as a result of adoption of treatments proved in randomized trials (e.g., thrombolytic, beta-adrenergic blocking and anticoagulant agents and aspirin). However, all trials are subject to selection biases, eligibility is limited for some therapies, and proved therapies may be underused even among eligible patients.

METHODS

Using administrative data from all general hospitals in Ontario, Canada, we analyzed 17,489, 17,839, 18,393, 18,794, 18,716 and 19,748 records of patients with a primary discharge diagnosis of myocardial infarction for fiscal years 1981, 1983, 1985, 1987, 1989 and 1991, respectively.

RESULTS

After age and gender adjustment, the overall relative reduction in in-hospital case fatality rates for the 10-year period was 26.9% (99% confidence interval [CI] 26.8% to 26.9%), corresponding to an absolute reduction of 6% (99% CI 5.6% to 6.4%). Age- and gender-standardized case fatality rate decreased from 22.3% in 1981 to 21.4% in 1985, followed by a highly significant decline to 16.3% in 1991. On the basis of the relation of comparative mortality to days of hospital stay, declining mortality was not an artifact of decreasing length of stay.

CONCLUSIONS

There have been encouraging improvements in survival after acute myocardial infarction over the past 6 years. Further improvements may require development of new therapies that can be more widely applied to this patient population.

Trends in coded causes of death following definite myocardial infarction and the role of competing risks: the Minnesota Heart Survey (MHS)

We investigated possible differences over time in underlying causes of death among validated definite myocardial infarction cases who were discharged following an index hospitalization in 1970, 1980, and 1985 in the Twin Cities, MN. No changes were observed in underlying causes of death assigned to patients who died prior to discharge in the 3 years. Among in-hospital survivors of definite MI, however, age-adjusted rates of death from non-cardiovascular causes more than doubled between 1970 and 1985 (P < 0.01). More specifically, mortality rates for diabetes mellitus increased significantly from 1970 to 1985 (P < 0.05), while those for neoplasms and diseases of the respiratory system increased non-significantly. Whether these data are the result of artifactual changes in cause of death assignment or real changes in disease severity and comorbidity, these trends in long-term death following acute MI may have had a modest impact on reported community-wide coronary heart disease mortality rates.

Impact of clinical trials on the use of beta blockers after acute myocardial infarction and its relation to other risk indicators for death and 1-year mortality rate

Based on selected patient populations, several randomized trials have shown beta blockers to decrease mortality after acute myocardial infarction (AMI). The purpose of this study was to describe the use of beta blockers in various subsets of patients admitted to Sahlgren's Hospital between February 15, 1986, and November 9, 1987, with AMI, and the relation of AMI to other risk indicators for death and to a 1-year mortality rate. Beta blockers, mainly metoprolol, were prescribed for 66% of all survivors at discharge. They were more frequently prescribed for younger patients and for those with a previous history of AMI and hypertension, but less frequently for those with a history of congestive heart failure and diabetes mellitus. Patients for whom beta blockers were not prescribed haa a 1-year mortality of 27% versus 11% for the rest (p < 0.001). Independent predictors of 1-year mortality after discharge were age (p < 0.001), history of hypertension (p < 0.001), prescription of beta blockers at discharge (p < 0.001), congestive heart failure during hospitalization (p < 0.001), and a history of AMI (p < 0.01). P values were corrected for baseline differences. Beta blockers were not prescribed at discharge for one-third of survivors after AMI. This group had a very high mortality during the first year. When simultaneously considering various risk indicators for death, prescription of beta blockers at discharge was associated with an increased rate of survival.

Determinants of 6-month mortality in survivors of myocardial infarction after thrombolysis. Results of the GISSI-2 data base. The Ad hoc Working Group of the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI)-2 Data Base

BACKGROUND

Current knowledge of risk assessment in survivors of myocardial infarction is largely based on data gathered before the advent of thrombolysis. It must be determined whether and to what extent available information and proposed criteria of prognostication are applicable in the thrombolytic era.

METHODS AND RESULTS

We reassessed risk prediction in the 10,219 survivors of myocardial infarction with follow-up data available (ie, 98% of the total) who had been enrolled in the GISSI-2 trial, relying on a set of prespecified variables. The 3.5% 6-month all-cause mortality rate of these patients compared with the higher value of 4.6% found in the corresponding GISSI-1 cohort, originally allocated to streptokinase therapy, indicates a 24% reduction in postdischarge 6-month mortality. On multivariate analysis (Cox model), the following variables were predictors of 6-month all-cause mortality: ineligibility for exercise test for both cardiac (relative risk [RR], 3.30; 95% confidence interval [CI], 2.36-4.62) and noncardiac reasons (RR, 3.28; 95% CI, 2.23-4.72), early left ventricular failure (RR, 2.41; 95% CI, 1.87-3.09), echocardiographic evidence of recovery phase left ventricular dysfunction (RR, 2.30; 95% CI, 1.78-2.98), advanced (more than 70 years) age (RR, 1.81; 95% CI, 1.43-2.30), electrical instability (ie, frequent and/or complex ventricular arrhythmias) (RR, 1.70; 95% CI, 1.32-2.19), late left ventricular failure (RR, 1.54; 95% CI, 1.17-2.03), previous myocardial infarction (RR, 1.47; 95% CI, 1.14-1.89), and a history of treated hypertension (RR, 1.32; 95% CI, 1.05-1.65). Early post-myocardial infarction angina, a positive exercise test, female sex, history of angina, history of insulin-dependent diabetes, and anterior site of myocardial infarction were not risk predictors. On further multivariate analysis, performed on 8315 patients with the echocardiographic indicator of left ventricular dysfunction available, only previous myocardial infarction was not retained as an independent risk predictor.

CONCLUSIONS

A decline in 6-month mortality of myocardial infarction survivors, seen within 6 hours of symptom onset, has been observed in recent years. Ineligibility for exercise test, early left ventricular failure, and recovery-phase left ventricular dysfunction are the most powerful (RR, > 2) predictors of 6-month mortality among patients recovering from myocardial infarction after thrombolysis. Qualitative variables reflecting residual myocardial ischemia do not appear to be risk predictors. The lack of an independent adverse influence of early post-myocardial infarction angina on 6-month survival represents a major difference between this study and those of the prethrombolytic era.

Geographical variation and time trends in the attack rate of coronary heart disease in five Swedish cities

Based upon community myocardial infarction (MI) records in five Swedish cities, geographical variation and time trends in the attack rate of fatal and non-fatal MI have been evaluated. During the study period 1975-1982, a total of 7699 events were registered among men and 1823 events among women. The mean annual mortality was highest in the north, and a declining gradient in mortality was observed from the northern to the southern part of the country. The out-of-hospital death rate was highest in the north, while no difference in in-hospital mortality was observed. However, the geographical variation in the morbidity of MI was less consistent. Changes over time generally followed the same pattern in all cities. The attack rate of fatal and non-fatal MI tended to decline among women and men aged 60-64 years. The pattern was less consistent among younger men. Among women aged 50-59 years the mortality remained unchanged, but the attack rate of non-fatal MI increased in all cities. This increase was not explained by inclusion of less severe infarctions. A considerable proportion, about 85%, were recorded as primary events, emphasizing the possible role of primary prevention in obtaining a decrease in the incidence of the disease. The results of this study support previous findings of an important regional difference in the mortality of MI in Sweden. However, the magnitude of the regional variation in the incidence of coronary heart disease might be overestimated if only the mortality pattern is studied.

Trends in survival of hospitalized myocardial infarction patients between 1970 and 1985. The Minnesota Heart Survey

BACKGROUND

The Minnesota Heart Survey is a population-based study designed to monitor and explain trends in cardiovascular mortality, morbidity, and risk factors. As part of this effort, a 50% sample of patients hospitalized for myocardial infarction (MI) in the seven-county Twin Cities (Minneapolis and St. Paul) metropolitan area was reviewed in 1970, 1980, and 1985. Those with a validated definite MI were followed for 4-year mortality. The purpose was to determine whether the improved survival observed between 1970 and 1980 was extended to the 1980-1985 period.

METHODS AND RESULTS

Crude 28-day mortality in men changed from 18% in 1970 to 12% in 1980 to 13% in 1985; in women it changed from 27% in 1970 to 22% in 1980 to 18% in 1985. After adjustment for severity factors (e.g., age, previous MI, and admission heart rate and systolic blood pressure), 28-day mortality was significantly lower in 1980 than in 1970 in men (RR, 0.66; 95% CI, 0.47, 0.92) and in women (RR, 0.69; 95% CI, 0.46, 1.04), but no change occurred from from 1980 to 1985 (p greater than 0.25). After adjustment for severity indicators, 4-year survival was better in 1980 than in 1970 for men (RR, 0.67; 95% CI, 0.54, 0.83) and for women (RR, 0.72; 95% CI, 0.54, 0.98), but there was no significant change from 1980 to 1985 (p greater than 0.25).

CONCLUSIONS

These results suggest that improvements in survival among hospitalized MI patients contributed to the overall decline in coronary heart disease mortality in the Twin Cities area between 1970 and 1980 but not between 1980 and 1985.

Did prognosis after acute myocardial infarction change during the past 30 years? A meta-analysis

Much effort has been spent to improve survival after acute myocardial infarction. To investigate how effective this effort has been, a meta-analysis was performed of studies published between 1960 and 1987 concerning mortality after acute myocardial infarction. Thirty-six studies were analyzed. They were classified with respect to deaths in the hospital and at 1 month and the 5-year mortality rate starting at hospital discharge. Mortality was assessed from all studies by comparing studies from different institutions with use of identical inclusion criteria (externally controlled studies) and by analyzing studies reporting on changes in mortality in two or more comparable patient cohorts admitted to the same institution at different time periods (internally controlled studies). Reports on clinical trials (for example, thrombolytic therapy, beta-adrenergic blockade) in acute myocardial infarction were excluded. Average overall in-hospital mortality decreased from 29% during the 1960s to 21% during the 1970s and to 16% during the 1980s. The externally controlled studies also showed a declining trend: from 1960 to 1969, 32%, from 1970 to 1979, 19% and from 1980 to 1987, 15%. The 1-month overall mortality rate decreased from 31% during the 1960s to 25% during the 1970s and 18% during the 1980s externally controlled studies. Most internally controlled studies also showed significant improvement in in-hospital and 1-month survival. In contrast, 5-year mortality after hospital discharge did not significantly decrease (33% from 1960 to 1969 and 33% from 1970 to 1979). It is concluded that in the prethrombolytic era, short-term prognosis after acute myocardial infarction has improved since 1960.(ABSTRACT TRUNCATED AT 250 WORDS)

Two-year survival after myocardial infarction

We have studied 773 consecutive cases (706 individuals) with definite myocardial infarction treated in the Coronary Care Unit at Danderyd Hospital in Stockholm during the period 1984-85. Hospital mortality was 12.9% in all patients and 8.9% in patients under 70 years of age. Six hundred and six patients were discharged from the hospital and followed up for 2 years. The 2-year mortality in ischaemic heart disease was 14.4% in all patients and 9.5% in patients under 70 years of age and, including all causes of death, 20.3% and 14.6%, respectively. Our policy for medical treatment included frequent use of beta-adrenergic blocking agents, even in heart failure, and restricted use of antiarrhythmic drugs and digitalis. A short delay of admission may have been beneficial for the result of different kinds of anti-ischaemic intervention. Furthermore, a routinely performed exercise ECG before discharge and after 6 weeks, as part of a structured follow-up, has improved our ability to detect complications at an early stage and to optimize medical treatment.

The applicability of the results of streamlined trials to clinical practice

During recent decades we have seen an encouraging development of trial methodology. Less effort, however, has been devoted to the application of findings of trials to the practice of medicine. We cannot expect results of controlled trials alone to determine standard therapy, for clinical judgements are also required. Both beneficial and adverse effects are often only detectable on the group level. There are generally very few indications that drug effects differ qualitatively in subgroups of patients. It is important not only to prove or disprove effects, but also to find out how to implement a proper therapy for a majority of eligible patients. Four examples from treatment after myocardial infraction show that drug usage may not always be based upon results of clinical trials. The adoption of Swedish guidelines for thrombolytic therapy in acute myocardial infarction is taken as an example of an apparently optimal application of trial results in practice.

Practical guidelines for drug therapy after myocardial infarction

Effective management of the postinfarction patient includes early assessment of direct complications such as angina pectoris, congestive heart failure and ventricular arrhythmias. Treatment of persistent ischaemia might call for early revascularisation. Early prevention of reocclusion with aspirin is recommended. It is advisable to correct blood lipid disturbances and to treat elevated blood pressure. beta-Blocking drugs have shown worthwhile reductions of both non-fatal and fatal recurrences, whereas calcium blockers and antiarrhythmic drugs have not been found to be effective. Anticoagulants have not been definitely effective in reducing mortality but seem to have some effects on non-fatal recurrences. Platelet active drugs, among which aspirin is the best documented, reduce the incidence of both non-fatal and fatal recurrences.

Use of hospital care and hospital case-fatality of myocardial infarction during three years' follow-up in Finland

The epidemiology and use of hospital care of myocardial infarction was studied at the population level with routinely collected hospital discharge data of the whole country during a three-year follow-up. The study population was a one-year-cohort of 13,520 patients with an acute myocardial infarction in 1981 in Finland. The incidence figures were comparable with the previous data attained from expensive and laborious special registries or population studies. With the possibility of record linkage and follow-up we could get information on the use of hospital care of these patients. We conclude that routinely collected hospital discharge data in Finland give information valuable for epidemiological studies, for the planning of health services and for the evaluation of hospital care.

A review of the evidence concerning the impact of medical measures on recent mortality and morbidity in the United States

Because it still is widely believed that one deadly disease after another is being eliminated, or diminished, largely because of medical interventions, there is little commitment to social change and even resistance to a reordering of national priorities. In this article we examine the contribution of medical measures to recent mortality changes in coronary heart disease, cancer, and stroke, which together account for two-thirds of total U.S. mortality and consume the vast majority of available resources. Morbidity changes are also examined and found to be not declining in a manner congruent with mortality and, in fact, increasing for some subgroups. Using a combined measure of mortality and morbidity (the probability of a life free of disability), it is demonstrated that although overall life expectancy has increased over several decades, most of this increase is in years of disability. Our late 20th century approach to the emerging AIDS pandemic (the frantic search for a "magic bullet"--either a treatment or a vaccine) belies any suggestion that the arguments and data presented concerning the modest contribution of medical measures are now passé.

Changes in severity of myocardial infarction and three year survival rates after myocardial infarction in Auckland, 1966-7 and 1981-2

Mortality from coronary heart disease has been declining steadily over the past 20 years in Auckland. The possibility that improved survival contributed to this decline was examined in patients who survived four weeks after myocardial infarction, changes in the severity of the disease being controlled for. Patients who had had myocardial infarction in 1966-7 (191 patients) or 1981-2 (203) were compared to determine whether three year survival rates had changed and the severity of the disease altered. With a coronary prognostic index taken as the measure of severity the 1981-2 group had significantly more severe myocardial infarctions than the 1966-7 group, but despite this the three year survival was significantly better (86% in the 1981-2 group v 75% in the 1966-7 group). These findings suggest that improved survival after myocardial infarction contributed to the decline in mortality.

Improvement in long-term survival among patients hospitalized with acute myocardial infarction, 1970 to 1980. The Minnesota Heart Survey

The mortality rate associated with coronary heart disease in the United States has declined steadily since 1968, but the reasons for this favorable trend have not been completely elucidated. In particular, it is not clear to what extent the decline reflects decreasing incidence as opposed to improved survival. To assess whether improved survival after myocardial infarction has contributed to the decline, the Minnesota Heart Survey compared the four-year survival rate in patients discharged with a diagnosis of acute myocardial infarction from hospitals in the Twin Cities area in 1970 and 1980. After adjustment for clinical characteristics related to outcome, the survival rate among patients with a definite myocardial infarction was significantly higher in the 1980 than in the 1970 group. The four-year survival for men was 35 percent better in the 1980 than in the 1970 group (95 percent confidence interval, 21 to 50 percent), and for women it was 27 percent better (95 percent confidence interval, 1 to 46 percent). Improvement in survival during the period of hospitalization accounted for 70 percent of the overall gain in survival between 1970 and 1980 in men and for virtually all of the gain in women. We conclude that improved long-term survival among patients with acute myocardial infarction has made an important contribution to the decline in mortality from coronary disease.

Prognostic importance of cholesterol levels after myocardial infarction

The aim of this study was to analyze the relationship between serum cholesterol level and all causes mortality in men who sustained a first myocardial infarction. The cholesterol distribution 3 months after the infarction was established. Ten annual cohorts (n = 1,204) were followed for a maximum period of 11 years. Secondary risk factors were comparable among the groups of the serum cholesterol distribution quintiles according to a multiple logistic prognostic function based on left heart failure, atrial fibrillation, breathlessness on infarction, maximum S-ASAT, relative heart size, and a history of hypertension. When all ages were analyzed together, the total mortality was higher in the upper cholesterol quintiles (P = 0.02). This association was confirmed when analyzed with Coxian adjustments for age, change in smoking habits after infarction, and the previously mentioned prognostic function. When broken down by age (less than or equal to 49, 50-59, greater than or equal to 60) and period of follow-up (3-24 and 25-84 months), the association between mortality and cholesterol quintiles was confined to patients under 50 years during the late follow-up period (P = 0.01), whereas there was no association for the other age groups.