Risk factors for sudden coronary death in the United States

Type 2 diabetes and in-hospital sudden cardiac arrest in ST-elevation myocardial infarction in the US

Aims

We aimed to assess the impact of diabetes on sudden cardiac arrest (SCA) in US patients hospitalized for ST-elevation myocardial infarction (STEMI).

Methods

We used the National Inpatient Sample (2005-2017) data to identify adult patients with STEMI. The primary outcome was in-hospital SCA. Secondary outcomes included in-hospital mortality, ventricular tachycardia (VT), ventricular fibrillation (VF), cardiogenic shock (CS), acute renal failure (ARF), and the revascularization strategy in SCA patients.

Results

SCA significantly increased from 4% in 2005 to 7.6% in 2018 in diabetes patients and from 3% in 2005 to 4.6% in 2018 in non-diabetes ones (p < 0.001 for both). Further, diabetes was associated with an increased risk of SCA [aOR = 1.432 (1.336-1.707)]. In SCA patients with diabetes, the mean age (SD) decreased from 68 (13) to 66 (11) years old, and mortality decreased from 65.7% to 49.3% during the observation period (p < 0.001). Compared to non-diabetes patients, those with T2DM had a higher adjusted risk of mortality, ARF, and CS [aOR = 1.72 (1.62-1.83), 1.52 (1.43-1.63), 1.25 (1.17-1.33); respectively] but not VF or VT. Those patients were more likely to undergo revascularization with CABG [aOR = 1.197 (1.065-1.345)] but less likely to undergo PCI [aOR = 0.708 (0.664-0.754)].

Conclusion

Diabetes is associated with an increased risk of sudden cardiac arrest in ST-elevation myocardial infarction. It is also associated with a higher mortality risk in SCA patients. However, the recent temporal mortality trend in SCA patients shows a steady decline, irrespective of diabetes.

Exercise based assessment of cardiac autonomic function in type 1 versus type 2 diabetes mellitus

Background

Cardiac autonomic neuropathy (CAN) is a complication of diabetes mellitus (DM) that is associated with increased mortality. Exercise-based assessment of autonomic function has identified diminished parasympathetic reactivation after exercise in type 2 DM. It is postulated herein, that this would be more prominent among those with type 1 DM.

Methods

Sixteen subjects with type 1 DM (age 32.9 ± 10.1 years), 18 subjects with type 2 DM (55.4 ± 8.0 years) and 30 controls (44.0 ± 11.6 years) underwent exercise-based assessment of autonomic function. Two 16-min submaximal bicycle tests were performed followed by 45 min of recovery. On the second test, atropine (0.04 mg/kg) was administered near end-exercise so that all of the recovery occurred under parasympathetic blockade. Plasma epinephrine and norepinephrine levels were measured at rest, during exercise, and during recovery.

Results

There were no differences in resting or end-exercise heart rates in the three groups. Parasympathetic effect on RR-intervals during recovery (p < 0.03) and heart rate recovery (p = 0.02) were blunted in type 2 DM. Type 1 DM had higher baseline epinephrine and norepinephrine levels (p < 0.03), and exhibited persistent sympathoexcitation during recovery.

Conclusions

Despite a longer duration of DM in the study patients with type 1 versus type 2 DM, diminished parasympathetic reactivation was not noted in type 1 DM. Instead, elevation in resting plasma catecholamines was noted compared to type 2 DM and controls. The variable pathophysiology for exercise-induced autonomic abnormalities in type 1 versus type 2 DM may impact prognosis.

Magnesium in CKD: more than a calcification inhibitor?

Magnesium fulfils important roles in multiple physiological processes. Accordingly, a tight regulation of magnesium homeostasis is essential. Dysregulated magnesium serum levels, in particular hypomagnesaemia, are common in patients with chronic kidney disease (CKD) and have been associated with poor clinical outcomes. In cell culture studies as well as in clinical situations magnesium levels were associated with vascular calcification, cardiovascular disease and altered bone-mineral metabolism. Magnesium has also been linked to diseases such as metabolic syndrome, diabetes, hypertension, fatigue and depression, all of which are common in CKD. The present review summarizes and discusses the latest clinical data on the impact of magnesium and possible effects of higher levels on the health status of patients with CKD, including an outlook on the use of magnesium-based phosphate-binding agents in this context.

Impaired fasting plasma glucose and type 2 diabetes are related to the risk of out-of-hospital sudden cardiac death and all-cause mortality

OBJECTIVE

The aim of the study was to determine whether impaired fasting plasma glucose (FPG) and type 2 diabetes may be risk factors for sudden cardiac death (SCD).

RESEARCH DESIGN AND METHODS

This prospective study was based on 2,641 middle-aged men 42-60 years of age at baseline. Impaired FPG level (≥5.6 mmol/L) among nondiabetic subjects (501 men) was defined according to the established guidelines, and the group with type 2 diabetes included subjects (159 men) who were treated with oral hypoglycemic agents, insulin therapy, and/or diet.

RESULTS

During the 19-year follow-up, a total of 190 SCDs occurred. The relative risk (RR) for SCD was 1.51-fold (95% CI 1.07-2.14, P = 0.020) for nondiabetic men with impaired FPG and 2.86-fold (1.87-4.38, P < 0.001) for men with type 2 diabetes as compared with men with normal FPG levels, after adjustment for age, BMI, systolic blood pressure, serum LDL cholesterol, smoking, prevalent coronary heart disease (CHD), and family history of CHD. The respective RRs for out-of-hospital SCDs (157 deaths) were 1.79-fold (1.24-2.58, P = 0.001) for nondiabetic men with impaired FPG and 2.26-fold (1.34-3.77, P < 0.001) for men with type 2 diabetes. Impaired FPG and type 2 diabetes were associated with the risk of all-cause death. As a continuous variable, a 1 mmol/L increment in FPG was related to an increase of 10% in the risk of SCD (1.10 [1.04-1.20], P = 0.001).

CONCLUSIONS

Impaired FPG and type 2 diabetes represent risk factors for SCD.

Risk factors for sudden cardiac death in post-menopausal women

OBJECTIVES

The aim of this study was to estimate the annual incidence rate of sudden cardiac death (SCD) and to identify risk factors for SCD in post-menopausal women.

BACKGROUND

With the aging U.S. population, post-menopausal women now have the greatest population burden of cardiovascular disease including SCD.

METHODS

We examined 161,808 women who participated in the Women's Health Initiative clinical trials and observational study. The women were recruited at 40 clinical sites across the United States, enrolled between 1993 and 1998, and followed until August 2009. Our primary endpoint is incident SCD, defined as death occurring within 1 h of symptom onset or within 1 h after the participant was last seen without symptoms and death that occurred in the absence of a potentially lethal non-coronary disease process.

RESULTS

Four hundred eighteen women experienced adjudicated SCD. The incidence rate of SCD was 2.4/10,000 women/year (95% confidence interval: 2.2 to 2.7). We identified the following independent risk factors for SCD: older age, African-American race, tobacco use, higher pulse, higher waist-to-hip ratio, elevated white blood cell count, history of heart failure, diabetes, history of myocardial infarction, previous carotid artery disease, and hypertension. Population-attributable fractions were greatest for hypertension, waist-to-hip ratio, and myocardial infarction.

CONCLUSIONS

Besides traditional risk factors for coronary heart disease, risk factors for sudden cardiac death in post-menopausal women include African-American race, higher pulse, higher waist-to-hip ratio, elevated white blood cell count, and heart failure. Nearly one-half of women who experienced sudden cardiac death had no previous diagnosis of coronary heart disease.

Low serum magnesium concentrations are associated with a high prevalence of premature ventricular complexes in obese adults with type 2 diabetes

BACKGROUND

Premature ventricular complexes (PVC) predict cardiovascular mortality among several adult populations. Increased arrhythmia prevalence has been reported during controlled magnesium (Mg) depletion studies in adults. We thus hypothesized that serum magnesium (sMg) concentrations are inversely associated with the prevalence of PVC in adults at high cardiovascular risk.

METHODS

Anthropometric, demographic and lifestyle characteristics were assessed in 750 Cree adults, aged > 18 yrs, who participated in an age-stratified, cross-sectional health survey in Quebec, Canada. Holter electrocardiograms recorded heart rate variability and cardiac arrhythmias for two consecutive hours. Multivariate logistic regression was used to evaluate the associations between sMg and PVC.

RESULTS

PVC prevalence in adults with hypomagnesemia (sMg ≤ 0.70 mmol/L) was more than twice that of adults without hypomagnesemia (50% vs. 21%, p = 0.015); results were similar when adults with cardiovascular disease history were excluded. All hypomagnesemic adults with PVC had type 2 diabetes (T2DM). Prevalence of PVC declined across the sMg concentration gradient in adults with T2DM only (p < 0.001 for linear trend). In multivariate logistic regressions adjusted for age, sex, community, body mass index, smoking, physical activity, alcohol consumption, kidney disease, antihypertensive and cholesterol lowering drug use, and blood docosahexaenoic acid concentrations, the odds ratio of PVC among T2DM subjects with sMg > 0.70 mmol/L was 0.24 (95% CI: 0.06-0.98) p = 0.046 compared to those with sMg ≤ 0.70 mmol/L.

CONCLUSIONS

sMg concentrations were inversely associated with the prevalence of PVC in patients with T2DM in a dose response manner, indicating that suboptimal sMg may be a contributor to arrhythmias among patients with T2DM.

Socioeconomic indicators and the risk of acute coronary heart disease events: comparison of population-based data from the United States and Finland

PURPOSE

We wished to determine whether a gradient of association of low socioeconomic status with incidence of coronary heart disease was present in two population-based cohorts, one from United States and the other from Finland.

METHODS

Using data from the Atherosclerosis Risk in Communities (ARIC) cohort and the Finnish FINRISK cohort, we estimated, with Cox proportional hazard regression models, incidence of sudden cardiac death (SCD), non-sudden cardiac death (NSCD), and non-fatal myocardial infarction (NFMI) for strata of income and education (follow-up: 1987-2001). In both cohorts, incidence rates of the three outcomes increased across all socioeconomic status exposure categories.

RESULTS

Low education was associated with increased hazard of NFMI in both cohorts and with increased risk of SCD among ARIC women. Low income was significantly associated with increased hazard of all three outcomes among ARIC women and with increased hazard of cardiac death among ARIC men. In FINRISK, low income was significantly associated with increased risk of SCD only. Risk of SCD in the low income categories was similar for both cohorts. Smoking, alcohol consumption, and race (ARIC only) did not appreciably alter effect estimates in either cohort.

CONCLUSIONS

Indices of low SES show similar associations with increased risk of cardiac events in Finland and in United States.

Diabetes and the risk of sudden cardiac death, the Atherosclerosis Risk in Communities study

Studies suggest that diabetes may specifically elevate the risk of sudden cardiac death in excess of other heart disease outcomes. In this study, we examined the association of type 2 diabetes with the incidence of sudden cardiac death when compared to the incidence of non-sudden cardiac death and non-fatal myocardial infarction (MI). We used data from the Atherosclerosis Risk in Communities (ARIC) study to examine the incidence of sudden and non-sudden cardiac death and non-fatal MI among persons with and without diabetes in follow-up from the baseline data collection (1987-1989) through December 31, 2001. There were 209 cases of sudden cardiac death, 119 of non-sudden cardiac death, and 739 of non-fatal MI identified in this cohort over an average 12.4 years of follow-up. In analyses adjusted for age, race/ARIC center, gender, and smoking, the Cox proportional hazard ratio of the association of baseline diabetes was 3.77 (95% CI 2.82, 5.05) for sudden cardiac death, 3.78 (95% CI 2.57, 5.53) for non-sudden cardiac death, and 3.20 (95% CI 2.71, 3.78) for non-fatal MI. Elevated risk for each of the three outcomes associated with diabetes was independent of adjustment for measures of blood pressure, lipids, inflammation, hemostasis, and renal function. Among those with diabetes, the risk of cardiac death, but not of non-fatal MI, was similar for men and women. Findings from this prospective, population-based cohort investigation indicate that diabetes does not confer a specific excess risk of sudden cardiac death. Our results suggest that diabetes attenuates gender differences in the risk of fatal cardiac events.

The case for hypoglycaemia as a proarrhythmic event: basic and clinical evidence

Recent clinical studies show that hypoglycaemia is associated with increased risk of death, especially in patients with coronary artery disease or acute myocardial infarction. This paper reviews data from cellular and clinical research supporting the hypothesis that acute hypoglycaemia increases the risk of malignant ventricular arrhythmias and death in patients with diabetes by generating the two classic abnormalities responsible for the proarrhythmic effect of medications, i.e. QT prolongation and Ca(2+) overload. Acute hypoglycaemia causes QT prolongation and the risk of ventricular tachycardia by directly suppressing K(+) currents activated during repolarisation, a proarrhythmic effect of many medications. Since diabetes itself, myocardial infarction, hypertrophy, autonomic neuropathy and congestive heart failure also cause QT prolongation, the arrhythmogenic effect of hypoglycaemia is likely to be greatest in patients with pre-existent cardiac disease and diabetes. Furthermore, the catecholamine surge during hypoglycaemia raises intracellular Ca(2+), thereby increasing the risk of ventricular tachycardia and fibrillation by the same mechanism as that activated by sympathomimetic inotropic agents and digoxin. Diabetes itself may sensitise myocardium to the arrhythmogenic effect of Ca(2+) overload. In humans, noradrenaline (norepinephrine) also lengthens action potential duration and causes further QT prolongation. Finally, both hypoglycaemia and the catecholamine response acutely lower serum K(+), which leads to QT prolongation and Ca(2+) loading. Thus, hypoglycaemia and the subsequent catecholamine surge provoke multiple, interactive, synergistic responses that are known to be proarrhythmic when associated with medications and other electrolyte abnormalities. Patients with diabetes and pre-existing cardiac disease may therefore have increased risk of ventricular tachycardia and fibrillation during hypoglycaemic episodes.

Model of cardiac arrest in rats by transcutaneous electrical epicardium stimulation

OBJECTIVE

To establish a new model of cardiac arrest (CA) in rats by transcutaneous electrical epicardium stimulation.

METHODS

Two acupuncture needles connected to the anode and cathode of a stimulator were transcutaneously inserted into the epicardium as electrodes. The stimulating current was steered to the epicardium and the stimulation was maintained for 3 min to induce CA. Cardiopulmonary resuscitation (CPR) was performed at 6 min after a period of nonintervention.

RESULTS

CA was successfully induced in a total of 20 rats. The success rate of induction was 12/20 at the current intensity of 1 mA; and reached 20/20 when the current intensity was increased to 2 mA. After the electrical stimulation, the femoral blood pressure quickly dropped below 25 mmHg and the arterial pulse waveform disappeared. The average time from the electrical stimulation to CA induction was 5.10 (+/-2.81) s. When the electrical stimulation stopped, 18/20 rats had ventricular fibrillation and 2/20 rats had pulseless electrical activity. CPR was performed for averagely 207.4 (+/-148.8) s. The restoration of spontaneous circulation (ROSC) was 20/20. The death rate within 4h after ROSC was 5/20, and the 72-h survival rate was 10/20. There were only two cases of complications, a minor muscle contraction and a minor lung lobe injury.

CONCLUSION

The model of CA in rats induced by transcutaneous electrical epicardium stimulation is a stable model that requires low-intensity current and has fewer complications. This model may provide another option for experimental research of CA induced by malignant arrhythmia (especially VF).

Smoking cessation pharmacotherapy

Cigarette smoking remains an important risk factor for premature cardiovascular disease and its many complications. There are clear benefits from treating tobacco dependence on the rate of clinical outcomes. In addition to behavioral therapies, various pharmacologic strategies have been developed to help achieve this goal. First-line therapies include nicotine replacement, bupropion and varenicline, a partial nicotine antagonist. Second-line treatments include clonidine and nortriptyline. Additional treatment strategies with less proven efficacy include monoamine oxidase inhibitors, selective serotonin reuptake inhibitors, opioid receptor antagonists, bromocriptine, anti-anxiety drugs, nicotinic receptor antagonists (e.g. mecamylamine) and glucose tablets. Various approaches under investigation include inhibitors of the hepatic P450 enzyme (e.g. methoxsalen), cannabinoid-1 receptor antagonists (e.g. rimonabant), and nicotine vaccines.

Atypical antipsychotic drugs and the risk of sudden cardiac death

BACKGROUND

Users of typical antipsychotic drugs have an increased risk of serious ventricular arrhythmias and sudden cardiac death. However, less is known regarding the cardiac safety of the atypical antipsychotic drugs, which have largely replaced the older agents in clinical practice.

METHODS

We calculated the adjusted incidence of sudden cardiac death among current users of antipsychotic drugs in a retrospective cohort study of Medicaid enrollees in Tennessee. The primary analysis included 44,218 and 46,089 baseline users of single typical and atypical drugs, respectively, and 186,600 matched nonusers of antipsychotic drugs. To assess residual confounding related to factors associated with the use of antipsychotic drugs, we performed a secondary analysis of users of antipsychotic drugs who had no baseline diagnosis of schizophrenia or related psychoses and with whom nonusers were matched according to propensity score (i.e., the predicted probability that they would be users of antipsychotic drugs).

RESULTS

Current users of typical and of atypical antipsychotic drugs had higher rates of sudden cardiac death than did nonusers of antipsychotic drugs, with adjusted incidence-rate ratios of 1.99 (95% confidence interval [CI], 1.68 to 2.34) and 2.26 (95% CI, 1.88 to 2.72), respectively. The incidence-rate ratio for users of atypical antipsychotic drugs as compared with users of typical antipsychotic drugs was 1.14 (95% CI, 0.93 to 1.39). Former users of antipsychotic drugs had no significantly increased risk (incidence-rate ratio, 1.13; 95% CI, 0.98 to 1.30). For both classes of drugs, the risk for current users increased significantly with an increasing dose. Among users of typical antipsychotic drugs, the incidence-rate ratios increased from 1.31 (95% CI, 0.97 to 1.77) for those taking low doses to 2.42 (95% CI, 1.91 to 3.06) for those taking high doses (P<0.001). Among users of atypical agents, the incidence-rate ratios increased from 1.59 (95% CI, 1 .03 to 2.46) for those taking low doses to 2.86 (95% CI, 2.25 to 3.65) for those taking high doses (P=0.01). The findings were similar in the cohort that was matched for propensity score.

CONCLUSIONS

Current users of typical and of atypical antipsychotic drugs had a similar, dose-related increased risk of sudden cardiac death.

Factors Associated with Sudden Death in Peritoneal Dialysis Patients

Background

Relatively little is known of the epidemiology and predictors of sudden death in peritoneal dialysis (PD) populations. We aimed to identify the risk factors of sudden death among PD subjects.

Methods

To explore clinical correlates of sudden death in PD patients, we conducted a population-based case-control study using data from a single dialysis unit. Cases ( n = 24) were defined as all PD patients that met the criteria for sudden death during January 2003 through December 2006. We also selected 48 control subjects that were selected from the prevalent PD patient name list compiled in alphabetical order. Data on the hemoglobin, potassium, and calcium levels, residual renal function, dialysis adequacy, cardiovascular risks, comorbid conditions, concurrent use of aspirin, beta-blockers, angiotensin-converting enzyme inhibitors, and erythropoietin, electrocardiographic and echocardiographic findings were extracted from case notes and computer records. Confounders were controlled by logistic regression.

Results

Over a period of 4 years, 24 PD patients (mean age 61.4 ± 9.5 years, median duration of dialysis 3.1 years) experienced sudden death. Univariate analyses showed that patients that died suddenly were more likely to be male and to have diabetes mellitus, a history of smoking, and a lower small solute clearance as measured by Kt/V. Cases of sudden death were also more likely to have received blood transfusion within the previous 1 year. There were no significant differences between patients and controls for residual renal function, serum potassium levels, control of blood pressure and mineral metabolism, or hemoglobin levels. Multivariate regression analysis confirmed independent association between recent blood transfusion and increased odds of sudden death [adjusted odds ratio (OR) 5.18, 95% confidence interval (CI) 1.44 – 18.6]. Two other factors significantly associated with risk of sudden death were male gender (adjusted OR 4.16, 95% CI 1.14 – 15.2) and diabetes mellitus (adjusted OR 5.33, 95% CI 1.53 – 18.6).

Conclusion

This study shows that recent blood transfusion is associated with an increased likelihood of sudden death in PD patients. The mechanisms that underlie this observation are unclear.

In vivo virtual histology intravascular ultrasound correlates of risk factors for sudden coronary death in men: results from the prospective, multi-centre virtual histology intravascular ultrasound registry

AIMS

We hypothesized a relationship between virtual histology intravascular ultrasound (VH-IVUS) findings and risk factors histopathologically associated with sudden coronary death (SCD) in men: cigarette smoking and an increased total cholesterol-to-high-density lipoprotein cholesterol (HDL-C) ratio (TC/HDL > 5).

METHODS AND RESULTS

We assessed volumetric VH-IVUS parameters in a consecutive series of 473 male patients: fibrous, fibro-fatty, dense calcium (DC), necrotic core (NC), and a calculated NC/DC ratio. Patients' age was 61 ± 11 years, with 27% smokers and 69% having a lipid disorder. The NC/DC ratio was the only VH-IVUS parameter related to both TC/HDL ratio (r = 0.18, P= 0.0008) and low-density lipoprotein cholesterol levels (r = 0.17, P= 0.002); had a negative correlation with HDL-C levels (r = -0.11, P= 0.03); and was higher for smokers [median 1.98 (1.35-3.18)] vs. non-smokers [median 1.70 (1.23-2.53), P= 0.006]. An NC/DC value >3 was the threshold that best identified smokers and/or patients presenting TC/HDL >5 (odds ratio 3.0, 95% CI 1.7-4.9, P= 0.0001), and receiver-operator curves showed the superiority of the NC/DC ratio [area under curve (AUC) 0.64, P < 0.0001] over %DC (AUC 0.58, P= 0.006) or %NC (AUC 0.51, P= 0.43) to identify these patients.

CONCLUSION

The ratio of NC to calcification detected by VH-IVUS in diseased coronary segments is related to known risk factors for SCD and, thus, may be associated with a worse prognosis.

Smoking Cessation Pharmacotherapy?Nicotine and Non-Nicotine Preparations

Cigarette smokers tend to die prematurely from a number of diseases. Cigarette smoking is an important modifiable risk factor for cardiovascular morbidity and mortality. Despite the clear health benefits of smoking cessation, smokers usually find it difficult to stop and behavioral therapies often prove insufficient. Pharmacologic intervention may aid the process because of the addictive nature of nicotine. Nicotine replacement therapy, which is regarded as first-line therapy, was developed to overcome the symptoms of nicotine withdrawal that many patients find distressing. Different modes of administration include inhalation and buccal or transdermal absorption. The orally administered non-nicotine drugs varenicline and bupropion are also regarded as first-line treatments, either used alone or as an adjunct to nicotine replacement therapy. Second-line treatments include clonidine and nortriptyline. Other treatment strategies that have been examined include monoamine oxidase inhibitors and selective serotonin reuptake inhibitors; efficacy has yet to be proven definitively. A novel approach to treatment using the cannabinoid-1 receptor antagonist rimonabant is also under investigation.

Dysrhythmia and electrocardiographic changes in diabetes mellitus: pathophysiology and impact on the incidence of sudden cardiac death

BACKGROUND

The incidence of sudden cardiac death (SCD) is increasing in diabetes mellitus. Susceptibility to dysrhythmias and the reliability of an electrocardiogram in diabetic hearts are debatable issues.

OBJECTIVES

To highlight the underlying mechanism of dysrhythmia and electrocardiographic changes in diabetic patients and the impact on the incidence of SCD.

METHODS

Most the pertinent articles (English and non-English) published in Medline, Scopus and EBSCO Host research databases have been reviewed.

RESULTS AND CONCLUSION

In the absence of systematic reviews, susceptibility to dysrhythmias and electrical instability in diabetic patients are underestimated. This susceptibility has been found to be enhanced, unchanged or reduced in different studies. To find a link between SCD and diabetes, the published studies provide controversial results; however, the majority of studies with a long-term follow-up support this link. The role of hyperglycemia, autonomic neuropathy and anti-diabetic agents as predisposing factors deserve more attention to fortify the clinical judgment and decrease the incidence of SCD.

Diabetes, glucose level, and risk of sudden cardiac death

AIMS

The prevalence of diabetes mellitus in industrialized countries is rapidly increasing, and diabetes is suspected to carry a particular high risk for sudden cardiac death (SCD).

METHODS AND RESULTS

We conducted a population-based case-control study at Group Health Cooperative. Cases (n=2040) experienced out-of-hospital cardiac arrest due to heart disease between 1980 and 1994. Controls (n=3800) were a stratified random sample of enrollees. Diabetes status was classified into four exclusive groups: (i) no diabetes, (ii) borderline, (iii) diabetes without microvascular disease (retinopathy or proteinuria), and (iv) diabetes with microvascular disease. When compared with no diabetes, we observed progressively higher risk of SCD associated with borderline diabetes [Odds ratio (OR)=1.24 (0.98-1.57)], diabetes without microvascular disease [OR=1.73 (1.28-2.34)], and diabetes with microvascular disease [OR=2.66 (1.84-3.85)], after adjustment for potential confounders (P-value for trend <0.001). Higher glucose levels were also associated with the risk of SCD both in the absence and in the presence of microvascular disease. However, subjects with microvascular complications but with glucose level <7.7 mmol/L were not at significant increased risk of SCD.

CONCLUSION

These results emphasize the role of diabetes as a strong risk factor for SCD and outline the importance of glucose level at every stage of diabetes severity.

Current smoking and the risk of non-fatal myocardial infarction in the WHO MONICA Project populations

BACKGROUND

Cohort studies have shown that smoking has a substantial influence on coronary heart disease mortality in young people. Population based data on non-fatal events have been sparse, however.

OBJECTIVE

To study the impact of smoking on the risk of non-fatal acute myocardial infarction (MI) in young middle age people.

METHODS

From 1985 to 1994 all non-fatal MI events in the age group 35-64 were registered in men and women in the WHO MONICA (multinational monitoring of trends and determinants in cardiovascular disease) project populations (18,762 events in men and 4047 in women from 32 populations from 21 countries). In the same populations and age groups 65,741 men and 66,717 women participated in the surveys of risk factors (overall response rate 72%). The relative risk of non-fatal MI for current smokers was compared with non-smokers, by sex and five year age group.

RESULTS

The prevalence of smoking in people aged 35-39 years who experienced non-fatal MI events was 81% in men and 77% in women. It declined with increasing age to 45% in men aged 60-64 years and 36% in women, respectively. In the 35-39 years age group the relative risk of non-fatal MI for smokers was 4.9 (95% confidence interval (CI) 3.9 to 6.1) in men and 5.3 (95% CI 3.2 to 8.7) in women, and the population attributable fractions were 65% and 55%, respectively.

CONCLUSIONS

During the study period more than half of the non-fatal MIs occurring in young middle age people can be attributed to smoking.

Post-myocardial infarction smoking cessation counseling: associations with immediate and late mortality in older Medicare patients

PURPOSE

To assess the difference in immediate (30 and 60 days after admission) and late (2-year) mortality between those who received inpatient post-myocardial infarction smoking cessation counseling and those who did not receive counseling.

METHODS

We conducted an observational study of a national random sample of inpatients from 2971 U.S. acute care hospitals participating in the Cooperative Cardiovascular Project in 1994-95. Medicare beneficiaries who were current smokers over age 65, admitted with a documented acute myocardial infarction, and who were discharged to home were included (n=16743). Our main outcome measures were early (30-, 60-day) and late (1-, 2-year) mortality.

RESULTS

Smoking cessation counseling was documented during their index hospitalization for 41% of patients. Compared with those not counseled, those who received inpatient counseling had lower 30-day (2.0% vs. 3.0%), 60-day (3.7% vs. 5.6%), and 2-year mortality (25.0% vs. 30%) (logrank P <0.0001). After adjustment for demographic characteristics, comorbid conditions, APACHE score, and receipt of treatments including aspirin, reperfusion, beta-blockers, and angiotensin-converting enzyme inhibitors, those receiving counseling were less likely to die within 1 year, but the effect was lost between 1 and 2 years [hazard ratio (HR) = 0.99 (0.91-1.10)]. The greatest reduction in relative hazard (19%) was seen within 30 days [HR = 0.81 (95% confidence interval 0.65-0.99)].

CONCLUSION

Immediate and long-term mortality rates were lower among those receiving inpatient smoking cessation counseling.

Intense management of diabetes mellitus: role of glucose control and antiplatelet agents

Type 2 diabetes has now reached epidemic proportions across the world and is the cause of substantial morbidity and mortality. Patients with diabetes suffer from their mircovascular complications of retinopathy (blindness), nephropathy (renal failure, dialysis), and neuropathy (neropathic pain, trophic ulcers). However, ultimately, the majority of diabetics will die from macrovascular cardiovascular disease. Not only does cardiovascular disease develop earlier in the presence of diabetes, mortality from cardiovascular disease is increased by a factor of two to three in persons with diabetes as compared with the general population. To reduce this increased risk, a multifactorial approach to the management of type 2 diabetes has been advocated. The American Diabetes Association recommends not only good glycemic control but also identification and aggressive treatment of associated cardiovascular risk factors, with more stringent target levels for lipids and blood pressure than those recommended for the general population. Studies have shown that an intensified and goal-oriented approach to the treatment of type 2 diabetes addressing tight glucose control, optimal lipid and blood pressure management and the use of antiplatelet agents like aspirin reduces cardiovascular events, as well as nephropathy, retinopathy, and neuropathy.

The incidence of sudden cardiac death in the general population

BACKGROUND AND OBJECTIVES

To determine the incidence of sudden cardiac death in a general (Dutch) population.

METHODS

Cohort study in the Integrated Primary Care Information (IPCI) project, a database with all medical data from 150 general practices in The Netherlands. The study population comprised 249,126 subjects with a mean follow-up of 2.54 years.

RESULTS

In this period 4,892 deaths were identified, 582 of which were classified as (probable) sudden cardiac death. The overall incidence of sudden cardiac death in this population was 0.92 cases per 1,000 person-years (95%CI: 0.85-0.99). The risk was 2.3-fold higher in men than in women, and increased with age. The incidence of sudden cardiac death peaked in October and was lowest in August.

CONCLUSIONS

The incidence of sudden cardiac death in the general Dutch population was almost 1 per 1,000 person-years per year during the period 1 January, 1995 to 1 April, 2001. Most of the cases occurred at home.

Smokers in Västerbotten County, Sweden. What contributes to increased cardiovascular risk among heavy smokers?

OBJECTIVE

To analyse risk factor levels and risk factor patterns among heavy smokers compared to never smokers.

DESIGN

An incident case-referent study.

SETTING

The study was nested within the Västerbotten Intervention Programme (VIP).

SUBJECTS

286 people (62 women and 224 men) claimed to be heavy smokers, i.e. smoked 25 cigarettes or more per day. For each of them, two referents (who reported never to have been smokers) were matched on age and gender (572 referents).

MAIN OUTCOME MEASURES

Differences in biomedical variables and social and lifestyle factors were confirmed.

RESULTS

S-cholesterol, s-triglycerides, fasting blood glucose, body weight and body mass index were all significantly elevated among the heavy smokers. Some gender differences were also found. Social and lifestyle factors differed significantly between heavy smokers and never smokers, but without gender differences.

CONCLUSIONS

Heavy smokers carry a risk factor pattern corresponding to an increased risk of developing cardiovascular disease. Unfavourable changes in serum lipids and in glucose metabolism can exacerbate other deleterious effects of tobacco smoke on the cardiovascular system. Obviously, heavy smokers and never smokers differ not only in regard to biomedical variables but also to lifestyle and social health determinants. These are important factors to consider in public health efforts aimed at reducing the increased risk for cardiovascular diseases among smokers.

Epidemiology of smoking-induced cardiovascular disease

Cigarette smoking is a major cause of coronary heart disease, stroke, aortic aneurysm, and peripheral vascular disease. The risk is manifest both as an increased risk for thrombosis of narrowed vessels and as an increased degree of atherosclerosis in those vessels. The cardiovascular risks owing to cigarette smoking increase with the amount smoked and with the duration of smoking. Risks are not reduced by smoking cigarettes with lower machine-measured yields of tar and nicotine, but those who have only smoked pipes or cigars seem to have a lower risk for cardiovascular diseases. Cessation of cigarette smoking reduces disease risks, although risks may remain elevated for a decade or more after cessation.

Platelet collagen receptor GPIa (C807T/HPA-5) haplotype is not associated with an increased risk of fatal coronary events in middle-aged men

Platelet GPIa/IIa receptors play key roles in the adhesion of platelets to collagen during the formation of coronary thrombosis. The C807T and HPA-5 polymorphisms of the gene for GPIa define three distinct alleles of GPIa which are associated with the surface expression of the protein in an allele-dependent fashion. Significance of these polymorphisms in victims of sudden cardiac death (SCD) was studied in Helsinki Sudden Death Study (HSDS) comprising 700 autopsied middle-aged Caucasian Finnish men with 288 SCD victims and 84 men with fatal acute myocardial infarction (AMI). The high-expression A1 allele was found in 36.6% of control men as opposed to 38.0% of all SCD victims and 36.9% of men with fatal AMI (P>0.4). The high-expression A1A1 genotype was found in 11.9% of men with fatal AMI and 10.0% of controls as opposed to the low-expression A2A2 genotype which was found in 29.8% of men with fatal AMI and in 31.2% of controls (OR 1.2, P>0.3). Age group (under/over 55) had no effect on the results. Our results do not support an effect of the GPIa haplotype on fatal coronary events among middle-aged men.

Glucose, blood pressure, and lipid control in older people with and without diabetes mellitus: the Cardiovascular Health Study

OBJECTIVES

To determine the prevalence of cardiovascular risk-factor treatment and control in older adults with normal fasting glucose, impaired fasting glucose, and diabetes mellitus and whether those with diabetes mellitus had better risk factor control than older adults with normal fasting glucose.

DESIGN

Secondary analysis of data from population-based, prospective cohort study of risk factors for cardio-vascular and cerebrovascular disease in older people (Cardiovascular Health Study).

SETTING

Community-based.

PARTICIPANTS

Community-dwelling adults aged 65 and older.

MEASUREMENTS

Fasting plasma glucose, serum cholesterol and its subfractions, systolic and diastolic blood pressures, and body mass index.

RESULTS

There were 579 (18%) cohort members with diabetes mellitus (77% receiving antidiabetic medication, 23% with fasting glucose > or =126 mg/dL and no treatment), 213 (6%) with impaired fasting glucose, and 2,582 (77%)with normal fasting glucose. Of diabetic participants, 12% had recommended fasting glucose levels of less than 110 mg/dL. Of participants with hypertension, a larger proportion of diabetic participants than nondiabetic participants (89% versus 75%, P < .01) was treated with antihypertensive agents, but a smaller proportion of diabetic participants had recommended blood pressure levels of 129/85 mmHg or lower than nondiabetic participants had recommended blood pressure levels of 139/89 mmHg or lower (27% vs 48%, P < .01). Diabetic dyslipidemic participants were treated less often with lipid-lowering therapy (26% versus 55%, P < .01) and achieved recommended low-density lipoprotein goals less often (8%versus 54%, P < .01) than nondiabetic dyslipidemic participants.

CONCLUSIONS

Overall, treatment and control of cardiovascular risk factors were suboptimal in this older population, especially among those with diabetes mellitus. Optimizing risk-factor control can improve health outcomes in older adults with and without diabetes mellitus.

Geographical pattern of female deaths from myocardial infarction in an urban population: fatal outcome out-of-hospital related to socio-economic deprivation

OBJECTIVE

This study of myocardial infarction (MI) amongst urban women has sought to assess whether there are differences in fatal outcome, in-hospital respectively out-of-hospital, between residential areas defined in terms of socio-economic circumstances.

DESIGN

Register-based surveillance study 1986-95.

SETTING

Seventeen residential areas in the city of Malmö, Sweden.

SUBJECTS

Women 20-74 years of age.

MAIN OUTCOME MEASURES

Differences in fatal outcome, in-hospital respectively out-of-hospital, between residential areas were expressed in terms of age-adjusted odds ratios (ORs), calculated by means of logistic regression. Socio-economic circumstances in the areas were expressed in terms of a composite score.

RESULTS

Between residential areas there were marked and statistically significant differences in incidence (range 124-328/10(5), P < 0.001, d.f.=16) and mortality (range 38-132/10(5), P < 0.005, d.f.=16). Area rates of mortality covaried with incidence (r=0.85, P < 0.001) and with odds ratios of fatal outcome out-of-hospital (r=0.52, P=0.031) but not in-hospital. The odds ratios of fatal outcome out-of-hospital decreased in a statistically significant stepwise fashion from areas in the lowest socio-economic quintile (reference) to areas in the highest socio-economic quintile (OR: 0.67, 95% CI: 0.48-0.94). There was no corresponding association with the odds ratios of fatal outcome in-hospital.

CONCLUSIONS

The high rate of mortality from MI amongst women in areas with deprived socio-economic circumstances was related to deaths occurring out-of-hospital. In order to assess the preventive potential there is a need for further studies that may clarify to what extent the association with socio-economic circumstances can be explained by other factors and conditions known to influence the probability of survival.

Plasma triglyceride-rich lipoprotein remnants as a risk factor of 'Pokkuri disease'

In our recent report, it remained unclear whether or not triglyceride-rich lipoprotein remnants (RLP) were associated with the risk of sudden coronary death in younger cases without coronary atherosclerosis that were detected in about 10% of all sudden coronary death cases in Japan. These cases were categorized as 'origin unknown, but suspected to be due to coronary spasm', the so called 'pokkuri disease' in Japan. The present study population consisted of 108 sudden death cases without coronary atherosclerosis [(pokkuri disease n=57) and non-cardiac sudden death (control n=51)] aged 20-69 years from Kanagawa prefecture in Japan. All individuals had died suddenly and unexpectedly, most had no significant history of medical conditions including cardiac symptoms and had not taken medications prior to death according to their medical records. All the autopsies were performed within 12 h after death. Plasma total cholesterol (TC), triglycerides (TG), phospholipids, RLP-C and RLP-TG, VLDL-C, LDL-C, HDL-C, apolipoproteins A-I, A-II, B, C-II, C-III, E, Lp (a) and homocysteine were measured in postmortem plasma samples. The TG-rich lipoprotein remnants measured as RLP-C and RLP-TG were significantly higher in pokkuri disease compared with controls both in fasting and postprandial states (P<0.05 and P<0.001), indicating that RLP-C and RLP-TG were the most significant risk factor in pokkuri disease among the parameters tested in this study. In conclusion the TG level in RLP (RLP-TG) appeared to be strongly associated with the risk of sudden death in the absence of coronary atherosclerosis (pokkuri disease).

Glycoprotein IIIa Pl(A1/A2) polymorphism and sudden cardiac death

OBJECTIVES

We studied the association of the Pl(A1/A2) polymorphism with coronary thrombosis, myocardial infarction (MI) and sudden cardiac death (SCD) in autopsied victims of sudden death.

BACKGROUND

Sudden cardiac death is one of the leading symptoms of coronary heart disease in early middle age. Platelet glycoprotein (GP)IIb/IIIa fibrinogen receptors play a key role in coronary thrombosis and MI. Pl(A1/A2) polymorphism of the gene for GPIIIa has been previously studied in hospital MI patients. Significance of the Pl(A1/A2) polymorphism in victims of SCD is not known.

METHODS

The Pl(A1/A2) polymorphism was studied in the Helsinki Sudden Death Study comprising 700 autopsied middle-aged white Finnish men (33 to 70 years, mean 53 years) who suffered sudden or violent out-of-hospital death.

RESULTS

Prevalence of the A2 allele decreased with age in the series. This decrease was observed among victims of SCD (n = 281) but not in men who died violently (n = 258) or of other diseases (n = 127). Of SCD victims below 50 years, 39.7% were carriers of the A2 allele compared with 28.3% among men under 50 who died of other causes (odds ratio [OR] 2.5, p = 0.01). Men with acute fatal coronary thrombosis (n = 39) were more often (OR 3.4, p < 0.01) carriers of the A2 allele than were men (n = 242) with SCD in the absence of acute coronary thrombosis (48.7% vs. 24.4%, respectively). In addition, men with MI and recent or old thrombosis (n = 67) were more often (OR 3.6, p = 0.005) carriers of the A2 allele than were men (n = 123) with MI in the absence of thrombosis (44.8% vs. 20.3%, respectively). These associations were especially strong in men under 60.

CONCLUSIONS

Our results suggest that the A2 allele of the Pl(A1/A2) polymorphism of GPIIIa is a major risk factor of coronary thrombosis and may be one important predictor of SCD in early middle age.

Risk factors and triggers of sudden death in the working generation: an autopsy proven case-control study

In Japan, studies on the risk factors of sudden death in the working generation have been rarely carried out, especially among extremely rare cases of causative disease. Thus, the present study aimed to identify the risk factors and triggers of sudden death in cases whose causes of death were definitely proven by autopsy. We investigated the legal medical records for four years from May 1994 to February 1998. Out of 271 cases, 176 patients 20 to 59 years were enrolled as cases of sudden death in the working generation. Among these, 91 cases, 52%, could be analyzed by telephone interviews from close family members. Only one examiner undertook all phone questions to the case subjects. As control subjects, 1167 persons who consulted us for a health check were employed. Of the sudden death cases, the final diagnosis in 29 cases was coronary artery disease (31.9%), 18, acute cardiac dysfunction (19.8%), 6, other cardiac diseases (6.6%), 4, acute aortic dissection (4.4%), 4, cerebrovascular disease (4.4%) and 30, other diseases (32.9%). Through conditional logistic analysis, the following risk factors emerged as candidates: Long-term stress, history of heart disease, hypertension, chest symptoms, autonomic disturbance, short-term stress and a smoking habit. Short-term stress, autonomic disturbance and a smoking habit increased the risk of sudden death due to coronary artery disease. Long-term stress was associated with an increased risk of sudden death due to acute cardiac dysfunction. It was also demonstrated that autonomic disturbance and stress were closely related to the occurrence of sudden death. Therefore, to prevent sudden death, it would be helpful to identify subjective symptoms to relieve such stress in some way.