Out-of-hospital coronary death in an urban population--validation of death certificate diagnosis. The Minnesota Heart Survey

Volatile Hydrocarbon Exposures and Incident Coronary Heart Disease Events: Up to Ten Years of Follow-up among Deepwater Horizon Oil Spill Workers

BACKGROUND

During the 2010 Deepwater Horizon (DWH) disaster, response and cleanup workers were potentially exposed to toxic volatile components of crude oil. However, to our knowledge, no study has examined exposure to individual oil spill-related chemicals in relation to cardiovascular outcomes among oil spill workers.

OBJECTIVES

Our aim was to investigate the association of several spill-related chemicals [benzene, toluene, ethylbenzene, xylene, n-hexane (BTEX-H)] and total hydrocarbons (THC) with incident coronary heart disease (CHD) events among workers enrolled in a prospective cohort.

METHODS

Cumulative exposures to THC and BTEX-H across the cleanup period were estimated via a job-exposure matrix that linked air measurement data with self-reported DWH spill work histories. We ascertained CHD events following each worker's last day of cleanup work as the first self-reported physician-diagnosed myocardial infarction (MI) or a fatal CHD event. We estimated hazard ratios (HR) and 95% confidence intervals for the associations of exposure quintiles (Q) with risk of CHD. We applied inverse probability weights to account for bias due to confounding and loss to follow-up. We used quantile g-computation to assess the joint effect of the BTEX-H mixture.

RESULTS

Among 22,655 workers with no previous MI diagnoses, 509 experienced an incident CHD event through December 2019. Workers in higher quintiles of each exposure agent had increased CHD risks in comparison with the referent group (Q1) of that agent, with the strongest associations observed in Q5 (range of HR = 1.14 - 1.44 ). However, most associations were nonsignificant, and there was no evidence of exposure-response trends. We observed stronger associations among ever smokers, workers with ≤ high school education, and workers with body mass index < 30   kg / m 2 . No apparent positive association was observed for the BTEX-H mixture.

CONCLUSIONS

Higher exposures to volatile components of crude oil were associated with modest increases in risk of CHD among oil spill workers, although we did not observe exposure-response trends. https://doi.org/10.1289/EHP11859.

Fine particulate matter and incident coronary heart disease events up to 10 years of follow-up among Deepwater Horizon oil spill workers

BACKGROUND

During the 2010 Deepwater Horizon (DWH) disaster, in-situ burning and flaring were conducted to remove oil from the water. Workers near combustion sites were potentially exposed to burning-related fine particulate matter (PM2.5). Exposure to PM2.5 has been linked to increased risk of coronary heart disease (CHD), but no study has examined the relationship among oil spill workers.

OBJECTIVES

To investigate the association between estimated PM2.5 from burning/flaring of oil/gas and CHD risk among the DWH oil spill workers.

METHODS

We included workers who participated in response and cleanup activities on the water during the DWH disaster (N = 9091). PM2.5 exposures were estimated using a job-exposure matrix that linked modelled PM2.5 concentrations to detailed DWH spill work histories provided by participants. We ascertained CHD events as the first self-reported physician-diagnosed CHD or a fatal CHD event that occurred after each worker's last day of burning exposure. We estimated hazard ratios (HR) and 95% confidence intervals (95%CI) for the associations between categories of average or cumulative daily maximum PM2.5 exposure (versus a referent category of water workers not near controlled burning) and subsequent CHD. We assessed exposure-response trends by examining continuous exposure parameters in models.

RESULTS

We observed increased CHD hazard among workers with higher levels of average daily maximum exposure (low vs. referent: HR = 1.26, 95% CI: 0.93, 1.70; high vs. referent: HR = 2.11, 95% CI: 1.08, 4.12; per 10 μg/m3 increase: HR = 1.10, 95% CI: 1.02, 1.19). We also observed suggestively elevated HRs among workers with higher cumulative daily maximum exposure (low vs. referent: HR = 1.19, 95% CI: 0.68, 2.08; medium vs. referent: HR = 1.38, 95% CI: 0.88, 2.16; high vs. referent: HR = 1.44, 95% CI: 0.96, 2.14; per 100 μg/m3-d increase: HR = 1.03, 95% CI: 1.00, 1.05).

CONCLUSIONS

Among oil spill workers, exposure to PM2.5 from flaring/burning of oil/gas was associated with increased risk of CHD.

Developing a Standardized and Reusable Method to Link Distributed Health Plan Databases to the National Death Index: Methods Development Study Protocol

BACKGROUND

Certain medications may increase the risk of death or death from specific causes (eg, sudden cardiac death), but these risks may not be identified in premarket randomized trials. Having the capacity to examine death in postmarket safety surveillance activities is important to the US Food and Drug Administration's (FDA) mission to protect public health. Distributed networks of electronic health plan databases used by the FDA to conduct multicenter research or medical product safety surveillance studies often do not systematically include death or cause-of-death information.

OBJECTIVE

This study aims to develop reusable, generalizable methods for linking multiple health plan databases with the Centers for Disease Control and Prevention's National Death Index Plus (NDI+) data.

METHODS

We will develop efficient administrative workflows to facilitate multicenter institutional review board (IRB) review and approval within a distributed network of 6 health plans. The study will create a distributed NDI+ linkage process that avoids sharing of identifiable patient information between health plans or with a central coordinating center. We will develop standardized criteria for selecting and retaining NDI+ matches and methods for harmonizing linked information across multiple health plans. We will test our processes within a use case comprising users and nonusers of antiarrhythmic medications.

RESULTS

We will use the linked health plan and NDI+ data sets to estimate the incidences and incidence rates of mortality and specific causes of death within the study use case and compare the results with reported estimates. These comparisons provide an opportunity to assess the performance of the developed NDI+ linkage approach and lessons for future studies requiring NDI+ linkage in distributed database settings. This study is approved by the IRB at Harvard Pilgrim Health Care in Boston, MA. Results will be presented to the FDA at academic conferences and published in peer-reviewed journals.

CONCLUSIONS

This study will develop and test a reusable distributed NDI+ linkage approach with the goal of providing tested NDI+ linkage methods for use in future studies within distributed data networks. Having standardized and reusable methods for systematically obtaining death and cause-of-death information from NDI+ would enhance the FDA's ability to assess mortality-related safety questions in the postmarket, real-world setting.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/21811.

Disparities in Premature Cardiac Death Among US Counties From 1999-2017: Temporal Trends and Key Drivers

Background Disparities in premature cardiac death (PCD) might stagnate the progress toward the reduction of PCD in the United States and worldwide. We estimated disparities across US counties in PCD rates and investigated county-level factors related to the disparities. Methods and Results We used US mortality data for cause-of-death and demographic data from death certificates and county-level characteristics data from multiple databases. PCD was defined as any death that occurred at an age between 35 and 74 years with an underlying cause of death caused by cardiac disease based on International Classification of Diseases, Tenth Revision (ICD-10), codes. Of the 1 598 173 PCDs that occurred during 1999-2017, 60.9% were out of hospital. Although the PCD rates declined from 1999-2017, the proportion of out-of-hospital PCDs among all cardiac deaths increased from 58.3% to 61.5%. The geographic disparities in PCD rates across counties widened from 1999 (Theil index=0.10) to 2017 (Theil index=0.23), and within-state differences accounted for the majority of disparities (57.4% in 2017). The disparities in out-of-hospital PCD rates (and in-hospital PCD rates) associated with demographic composition were 36.51% (and 37.51%), socioeconomic features were 18.64% (and 18.36%), healthcare environment were 18.64% (and 13.90%), and population health status were 23.73% (and 30.23%). Conclusions Disparities in PCD rates exist across US counties, which may be related to the decelerated trend of decline in the rates among middle-aged adults. The slower declines in out-of-hospital rates warrants more precision targeting and sustained efforts to ensure progress at better levels of health (with lower PCD rates) against PCD.

Increasing Mortality From Premature Coronary Artery Disease in Women in the Rural United States

Background

Previous reports have described a leveling off of mortality from premature coronary artery disease (CAD). In recent years, the prevalence of cardiovascular risk factors has increased in rural communities and young adults.

Methods and Results

We extracted CAD mortality rates from the Centers for Disease Control and Prevention Wide‐Ranging Online Data for Epidemiologic Research (CDC WONDER) database from 1999 to 2017, focusing on mortality from premature CAD (defined as <65 years of age in women) and urban–rural differences. Variations in mortality rates over time, assessed with Joinpoint regression modeling, are expressed as estimated annual percentage change (95% CI) and stratified by urbanization, sex, age, and race. Age‐adjusted mortality rates decreased for women and men. Stratification by urbanization revealed that premature CAD mortality is stagnating among women in rural areas. However, this stagnation conceals a statistically significant increase in CAD mortality rates since 2009 in women aged 55 to 64 years (estimated annual percentage change: +1.4%; 95% CI, +0.3% to +2.5%) and since 1999 in women aged 45 to 54 years (estimated annual percentage change: +0.6%; 95% CI, +0.2% to 1.0%). Since 1999, mortality has been stagnating in the youngest group (aged 35–44 years; estimated annual percentage change: +0.2%; 95% CI, −0.4% to +0.8%). Stratification by race indicated an increase in mortality rates among white rural women. Premature CAD mortality remains consistently higher in the rural versus urban United States, regardless of sex, race, and age group.

Conclusions

Premature CAD mortality rates have declined over time. However, stratification by sex and urbanization reveals disparities that would otherwise remain concealed: CAD mortality rates have increased among women from rural areas since at least 2009.

Comparison of Expert Adjudicated Coronary Heart Disease and Cardiovascular Disease Mortality With the National Death Index: Results From the REasons for Geographic And Racial Differences in Stroke (REGARDS) Study

BACKGROUND

The National Death Index (NDI) is widely used to detect coronary heart disease (CHD) and cardiovascular disease (CVD) deaths, but its reliability has not been examined recently.

METHODS AND RESULTS

We compared CHD and CVD deaths detected by NDI with expert adjudication of 4010 deaths that occurred between 2003 and 2013 among participants in the REGARDS (REasons for Geographic And Racial Differences in Stroke) cohort of black and white adults in the United States. NDI derived CHD mortality had sensitivity 53.6%, specificity 90.3%, positive predictive value 54.2%, and negative predictive value 90.1%. NDI-derived CVD mortality had sensitivity 73.4%, specificity 84.5%, positive predictive value 70.6%, and negative predictive value 86.2%. Among NDI-derived CHD and CVD deaths, older age (odds ratios, 1.06 and 1.04 per 1-year increase) was associated with a higher probability of disagreement with the adjudicated cause of death, whereas among REGARDS adjudicated CHD and CVD deaths a history of CHD or CVD was associated with a lower probability of disagreement with the NDI-derived causes of death (odds ratios, 0.59 and 0.67, respectively).

CONCLUSIONS

The modest accuracy and differential performance of NDI-derived cause of death may impact CHD and CVD mortality statistics.

Coronary Heart Disease Mortality Declines in the United States From 1979 Through 2011: Evidence for Stagnation in Young Adults, Especially Women

BACKGROUND

Coronary heart disease (CHD) mortality rates have fallen dramatically over the past 4 decades in the Western world. However, recent data from the United States and elsewhere suggest a plateauing of CHD incidence and mortality among young women. We therefore examined recent trends in CHD mortality rates in the United States according to age and sex.

METHODS AND RESULTS

We analyzed mortality data between 1979 and 2011 for US adults ≥25 years of age. We calculated age-specific CHD mortality rates and compared estimated annual percentage changes during 3 approximate decades of data (1979-1989, 1990-1999, and 2000-2011). We then used Joinpoint regression modeling to assess changes in trends over time on the basis of inflection points of the mortality rates. Adults ≥65 years of age showed consistent mortality declines, which became even steeper after 2000 (women, -5.0%; men, -4.4%). In contrast, young men and women (<55 years of age) initially showed a clear decline in CHD mortality from 1979 until 1989 (estimated annual percentage change, -5.5% in men and -4.6% in women). However, the 2 subsequent decades saw stagnation with minimal improvement. Notably, young women demonstrated no improvements between 1990 and 1999 (estimated annual percentage change, 0.1%) and only -1% estimated annual percentage change since 2000. Joinpoint analyses provided consistent results.

CONCLUSIONS

The dramatic decline in CHD mortality since 1979 conceals major heterogeneities. CHD death rates in older groups are now falling steeply. However, young adults have experienced frustratingly small decreases in CHD mortality rates since 1990. The drivers of these major differences in CHD mortality trends by age and sex merit urgent study.

A Case-Only Study of Vulnerability to Heat Wave-Related Mortality in New York City (2000-2011)

BACKGROUND

As a result of climate change, the frequency of extreme temperature events is expected to increase, and such events are associated with increased morbidity and mortality. Vulnerability patterns, and corresponding adaptation strategies, are most usefully conceptualized at a local level.

METHODS

We used a case-only analysis to examine subject and neighborhood characteristics that modified the association between heat waves and mortality. All deaths of New York City residents from 2000 through 2011 were included in this analysis. Meteorological data were obtained from the National Climatic Data Center. Modifying characteristics were obtained from the death record and geographic data sets.

RESULTS

A total of 234,042 adult deaths occurred during the warm season of our study period. Compared with other warm-season days, deaths during heat waves were more likely to occur in black (non-Hispanic) individuals than other race/ethnicities [odds ratio (OR) = 1.08; 95% CI: 1.03, 1.12], more likely to occur at home than in institutions and hospital settings (OR = 1.11; 95% CI: 1.06, 1.16), and more likely among those living in census tracts that received greater public assistance (OR = 1.05; 95% CI: 1.01, 1.09). Finally, deaths during heat waves were more likely among residents in areas of the city with higher relative daytime summer surface temperature and less likely among residents living in areas with more green space.

CONCLUSION

Mortality during heat waves varies widely within a city. Understanding which individuals and neighborhoods are most vulnerable can help guide local preparedness efforts.

Redistribution of heart failure as the cause of death: the Atherosclerosis Risk in Communities Study

Background

Heart failure is sometimes incorrectly listed as the underlying cause of death (UCD) on death certificates, thus compromising the accuracy and comparability of mortality statistics. Statistical redistribution of the UCD has been used to examine the effect of misclassification of the UCD attributed to heart failure, but sex- and race-specific redistribution of deaths on coronary heart disease (CHD) mortality in the United States has not been examined.

Methods

We used coarsened exact matching to infer the UCD of vital records with heart failure as the UCD from 1999 to 2010 for decedents 55 years old and older from states encompassing regions under surveillance by the Atherosclerosis Risk in Communities (ARIC) Study (Maryland, Minnesota, Mississippi, and North Carolina). Records with heart failure as the UCD were matched on decedent characteristics (five-year age groups, sex, race, education, year of death, and state) to records with heart failure listed among the multiple causes of death. Each heart failure death was then redistributed to plausible UCDs proportional to the frequency among matched records.

Results

After redistribution the proportion of deaths increased for CHD, chronic obstructive pulmonary disease, diabetes, hypertensive heart disease, and cardiomyopathy, P < 0.001. The percent increase in CHD mortality after redistribution was the highest in Mississippi (12%) and lowest in Maryland (1.6%), with variations by year, race, and sex. Redistribution proportions for CHD were similar to CHD death classification by a panel of expert reviewers in the ARIC study.

Conclusions

Redistribution of ill-defined UCD would improve the accuracy and comparability of mortality statistics used to allocate public health resources and monitor mortality trends.

Obstructive sleep apnea and the risk of sudden cardiac death: a longitudinal study of 10,701 adults

OBJECTIVES

This study sought to identify the risk of sudden cardiac death (SCD) associated with obstructive sleep apnea (OSA).

BACKGROUND

Risk stratification for SCD, a major cause of mortality, is difficult. OSA is linked to cardiovascular disease and arrhythmias and has been shown to increase the risk of nocturnal SCD. It is unknown if OSA independently increases the risk of SCD.

METHODS

We included 10,701 consecutive adults undergoing their first diagnostic polysomnogram between July 1987 and July 2003. During follow-up up to 15 years, we assessed incident resuscitated or fatal SCD in relation to the presence of OSA, physiological data including the apnea-hypopnea index (AHI), and nocturnal oxygen saturation (O2sat) parameters, and relevant comorbidities.

RESULTS

During an average follow-up of 5.3 years, 142 patients had resuscitated or fatal SCD (annual rate 0.27%). In multivariate analysis, independent risk factors for SCD were age, hypertension, coronary artery disease, cardiomyopathy or heart failure, ventricular ectopy or nonsustained ventricular tachycardia, and lowest nocturnal O2sat (per 10% decrease, hazard ratio [HR]: 1.14; p = 0.029). SCD was best predicted by age >60 years (HR: 5.53), apnea-hypopnea index >20 (HR: 1.60), mean nocturnal O2sat <93% (HR: 2.93), and lowest nocturnal O2sat <78% (HR: 2.60; all p < 0.0001).

CONCLUSIONS

In a population of 10,701 adults referred for polysomnography, OSA predicted incident SCD, and the magnitude of risk was predicted by multiple parameters characterizing OSA severity. Nocturnal hypoxemia, an important pathophysiological feature of OSA, strongly predicted SCD independently of well-established risk factors. These findings implicate OSA, a prevalent condition, as a novel risk factor for SCD.

Time trends and predictors of mortality from ill-defined causes in old age: 9 year folllow-up of the Bambuí cohort study (Brazil)

The study objective was to examine differentials in time trends and predictors of deaths assigned to symptoms, signs and ill-defined conditions in comparison with other ill-defined conditions (ill-defined cardiovascular diseases, cancer and injury) in a population-based cohort study. Of 1,606 baseline participants aged 60 years and over, 524 died during 9-year follow-up and were included in this study. Deaths coded to "symptoms" declined by 77% in the period from 1997-1999 to 2003-2005. Deaths coded to other ill-defined conditions remained unchanged. The calendar period 2003-2005 (RR = 0.25; 95%CI: 0.09-0.70) and in-hospital deaths (RR = 0.16; 95%CI: 0.08-0.34) were independently associated with "symptoms", but not with other ill-defined conditions. Baseline socio-demographic characteristics and chronic diseases were not predictors of these outcomes. International and national agencies have focused on the reduction of deaths assigned to "symptoms" to improve the registration of vital statistics, while other ill-defined conditions have received little attention. Our data provide evidence supporting the need to redress this situation.

Death in heart failure: a community perspective

BACKGROUND

Mortality in heart failure (HF) remains high but causes of death are incompletely defined. As HF is heterogeneous syndrome categorized according to ejection fraction (EF), the association between EF and causes of death is important, yet elusive.

METHOD AND RESULTS

Community subjects with HF were classified according to preserved (> or =50%) and reduced EF (<50%). Deaths were classified as coronary heart disease (CHD), other cardiovascular and non-cardiovascular. Among 1063 persons with HF, 45% had preserved EF with less cardiovascular risk factors and less coronary disease than those with reduced EF. At 5 years, survival was 45% (95% CI 43%-49%) and 43% of the deaths were non-cardiovascular. The leading cause of death in subjects with preserved EF was non-cardiovascular (49%) vs CHD (43%) for subjects with reduced EF. The proportion of cardiovascular deaths decreased from 69% in 1979-1984 to 40% in 1997-2002 (p=0.007) among subjects with preserved EF contrasting with a modest change among those with reduced EF (77% in to 64%, p=0.08). Advanced age, male sex, diabetes, smoking and kidney disease were associated with an increase risk of all cause and cardiovascular death. After adjustment, preserved EF was associated with a lower risk of cardiovascular death but not all cause death.

CONCLUSION

Community subjects with HF experience a persistently high mortality and a large proportion of deaths are non-cardiovascular. Subjects with preserved EF have less cardiovascular disease before death, are less likely to experience cardiovascular deaths than those with reduced EF and the proportion of cardiovascular deaths declined over time.

Discrepancies in initial death certificate diagnoses in sudden unexpected out-of-hospital deaths: the role of cardiovascular autopsy

BACKGROUND

The accuracy of death certificates issued for out-of-hospital sudden deaths has been questioned.

METHODS

We retrospectively studied a series of consecutive autopsies performed at two community hospitals.

RESULTS

Fifty-four autopsies in which the deaths were sudden and that occurred outside the hospital were retained for study. The indication for autopsy was largely driven by the wishes of family or physician who was uncertain about the diagnosis. The overall discrepancy rate was 52%. The death certificate diagnosis, rendered before autopsy, was coronary artery disease in 44/54 autopsies (81%). At autopsy, coronary artery disease was the cause of death in 26 cases (48%), cardiomyopathy in 10 (18%), ruptured aneurysm in 8 (15%), pulmonary embolism in 7 (13%), and valve disease in 3 (6%). The diagnosis of coronary artery disease on the death certificate was accurate only 50% of the time. The discrepancy rate was lowest in patients with a history of cardiovascular disease (33%) and was 60% in patients with no prior medical history. The accuracy rate of death certificates was under one third in cases of cardiomyopathy, valve disease, ruptured aneurysm, pulmonary embolism, and valve disease.

CONCLUSIONS

We conclude that in a highly selected group of sudden deaths, in which there was often a question about cause of death, the rate of initial death certificate accuracy is only one half. Furthermore, coronary artery disease as the cause of death is less than 50%, far less than initial death certificate diagnoses would indicate.

Retinal vessel diameter and cardiovascular mortality: pooled data analysis from two older populations

AIMS

The retinal microvasculature may reflect pre-clinical changes in the cerebral and coronary microcirculations. We assessed whether smaller retinal arterioles and larger venules predicted coronary heart disease (CHD)- and stroke-mortality.

METHODS AND RESULTS

We pooled data from the Beaver Dam Eye Study (n = 4926, aged 43-86) and the Blue Mountains Eye Study (n = 3654, aged 49-97). Retinal vessel diameters were measured from digitized retinal photographs. Change point models were used to assess and document the existence of threshold effects. We defined smaller arterioles as diameters within the narrowest quintile and larger venules as diameters within the widest quintile, with other quintiles as the reference. Of 8550 participants, 7494 (88%) with complete data were included, of whom 653 died from CHD and 299 from stroke over 10-12 years follow-up. After multivariable adjustment, each standard deviation (SD) increase in arteriolar diameter, or SD decrease in venular diameter, was not found to be significantly associated with either CHD-mortality or stroke-mortality. However, smaller arterioles [hazard ratio (HR) 1.34, 95% confidence interval (CI) 1.11-1.62] and larger venules (HR 1.24, CI 1.02-1.52), predicted increased risk of CHD-mortality. These associations were mainly evident among persons aged 43-69 (smaller arterioles: HR 1.70, CI 1.27-2.28; larger venules: HR 1.41, CI 1.06-1.89). Smaller arterioles (HR 1.64, CI 1.00-2.67) and larger venules (HR 1.53, CI 0.94-2.47) were also associated with an increased risk of stroke-mortality among persons aged 43-69.

CONCLUSION

Retinal vessel diameter may predict risk of CHD and stroke deaths in middle-aged persons.

Secular trends in deaths from cardiovascular diseases: a 25-year community study

BACKGROUND

Although age-adjusted cardiovascular disease (CVD) mortality has declined over the past decades, controversies remain about whether this trend was similar across locations of death and disease categories and about the existence of age and sex disparities.

METHODS AND RESULTS

We examined CVD mortality trends in Olmsted County, Minnesota, between 1979 and 2003 using the categories defined by the American Heart Association, including coronary heart disease (CHD), non-CHD diseases of the heart, and noncardiac circulatory diseases. Data on demographics, cause, and location of death of all 6378 residents who died of CVD were analyzed. Although decreases in the age-adjusted rates occurred in all groups, the magnitude of the decline varied widely. Lesser annual declines were noted in out-of-hospital than in-hospital deaths (1.8% versus 4.8%; P<0.001), in older than in younger persons (1.5% at age > or =85 years versus 3.9% for those < or =74 years of age; P<0.001), and in women relative to men (2.5% versus 3.3%; P=0.007). Furthermore, although CHD showed a marked annual decrease (3.3%), more modest decrements were found for non-CHD diseases of the heart (2.1%) and noncardiac circulatory diseases (2.4%) (P=0.02 and P=0.04 for the comparison with CHD decline, respectively).

CONCLUSIONS

Over the past 25 years, CVD mortality declined markedly in the community, but there were large disparities in the magnitude of the decline, resulting in a shift in the distribution toward out-of-hospital and non-CHD deaths. Further reduction in CVD mortality will require strategies directed at elderly persons and women, in whom out-of-hospital rates have improved only minimally.

Trends in community mortality due to coronary heart disease

BACKGROUND

Relatively little data are available, particularly from the more generalizable perspective of a population-based investigation, describing recent trends in death rates due to coronary heart disease (CHD). The objectives of this observational study were to describe changes over a twelve year period (1990-2001) in death rates due to CHD and acute myocardial infarction (AMI) in residents of the Worcester, Massachusetts, metropolitan area (2000 census = 478,000). A secondary study goal was to describe changes in death rates attributed to CHD over time separately in men and in women, in persons of different ages, and according to location of death.

METHODS

Death datatapes were obtained from the Massachusetts Department of Public Health for greater Worcester residents who died over the period 1990 to 2001.

RESULTS

Marked declines were observed in the population death rates (per 100,000) due to CHD (1990 death rate = 322; 2001 death rate = 224) and AMI (1990 death rate = 137; 2001 death rate = 87) in the greater Worcester population. Declines in the annual death rates attributed to CHD were observed in both the hospital (4.4% decline) and out-of-hospital setting (1.6% decline) as well as for patients dying from AMI (annual declines of 4.8% and 1.9% respectively). Reductions in CHD death rates over time were observed in men and in women and in persons of all ages.

CONCLUSIONS

The present results demonstrate encouraging declines in community death rates due to CHD and AMI over time and the impact of evolving primary and secondary prevention efforts.

Value of an Endpoints Committee versus the use of nosologists for validating cause of death

PURPOSE

Few studies have directly compared the use of nosologists versus other sources of mortality information deemed a gold standard, including the use of an Endpoints Committee (EC), which is commonly utilized in clinical studies.

METHODS

We conducted a study of 421 participants in the Physicians' Health Study (PHS), known to have died of confirmed causes during the period of April 1982 to January 1988. Classification of cause of death was compared when coded by certified nosologists directly from the death certificate without the availability of full hospital and medical records versus determinations made by the PHS Endpoints Committee (EC).

RESULTS

The sensitivity of the nosologists, using the PHS EC as the gold standard, was 90% for total cardiovascular death, 89% for cancer and 89% for other deaths. However, when considering more specific causes of death, sensitivity for acute MI, sudden cardiac deaths and deaths from other cardiovascular causes were lower. Specificity was generally excellent for all endpoints, ranging from 90% to 100%. In analyses stratified by age, nosologists tended to overestimate the frequency of cardiovascular deaths in the elderly.

CONCLUSIONS

Mortality endpoints classified by trained nosologists versus the PHS EC indicate that nosologists can review death certificates to reasonably and quickly classify broad categories of causes of death in men, whereas an EC remains the preferable strategy when more specific causes of death must be ascertained by reviewing medical records and other accompanying information.

Out-of-hospital cardiac deaths in adolescents and young adults in the United States, 1989 to 1998

BACKGROUND

Out-of-hospital cardiac death (OHCD), often occurring suddenly and unexpectedly, is a major public health problem. The purpose of this study is to assess the epidemiologic pattern and secular trend of OHCD in adolescents and young adults aged 15-34 years in the United States.

METHODS

United States national vital statistics mortality data from 1989 to 1998 were analyzed. OHCD was defined as death that occurred either at a pre-transport location, or in the emergency room, or was classified as "dead on arrival" in the emergency room, with an underlying cause of death as a cardiac disease (ICD-9 codes 390-398, 402, 404-429, 745, or 746).

RESULTS

Of the 48,573 cardiac deaths occurring during 1989 to 1998, 31,827 (66%) were out of hospital. Of all OHCD victims from 1989 to 1998, 70% were men, and 76% were aged 25-34 years. The leading underlying causes of OHCD were coronary heart disease (29%), cardiomyopathy (18%), and arrhythmias (14%). The OHCD rates (per million population) were twice as high in men as in women (57.0 vs. 26.7 in 1997 and 1998), in African Americans as in whites (84.9 vs. 35.9 in 1997 and 1998), and increased with age. From 1989-1990 to 1997-1998, the age-adjusted OHCD death rates increased in both men (11%) and women (33%), and in African Americans (11%) and whites (19%).

CONCLUSIONS

Although cardiac death remains rare in U.S. adolescents and young adults, the increased trend in OHCD rates in this age group warrants further investigation of etiology and prevention strategies.

Day-night pattern of sudden death in obstructive sleep apnea

BACKGROUND

The risk of sudden death from cardiac causes in the general population peaks from 6 a.m. to noon and has a nadir from midnight to 6 a.m. Obstructive sleep apnea is highly prevalent and associated with neurohormonal and electrophysiological abnormalities that may increase the risk of sudden death from cardiac causes, especially during sleep.

METHODS

We reviewed polysomnograms and the death certificates of 112 Minnesota residents who had undergone polysomnography and had died suddenly from cardiac causes between July 1987 and July 2003. For four intervals of the day, we compared the rates of sudden death from cardiac causes among people with obstructive sleep apnea and the following: the rates among people without obstructive sleep apnea, the rates in the general population, and the expectations according to chance. For each interval, we assessed the median apnea-hypopnea index and the relative risk of sudden death from cardiac causes. We similarly analyzed sudden death from cardiac causes during three time intervals that correlate with usual sleep-wake cycles.

RESULTS

From midnight to 6 a.m., sudden death from cardiac causes occurred in 46 percent of people with obstructive sleep apnea, as compared with 21 percent of people without obstructive sleep apnea (P=0.01), 16 percent of the general population (P<0.001), and the 25 percent expected by chance (P<0.001). People with sudden death from cardiac causes from midnight to 6 a.m. had a significantly higher apnea-hypopnea index than those with sudden death from cardiac causes during other intervals, and the apnea-hypopnea index correlated directly with the relative risk of sudden death from cardiac causes from midnight to 6 a.m. For people with obstructive sleep apnea, the relative risk of sudden death from cardiac causes from midnight to 6 a.m. was 2.57 (95 percent confidence interval, 1.87 to 3.52). The analysis of usual sleep-wake cycles showed similar results.

CONCLUSIONS

People with obstructive sleep apnea have a peak in sudden death from cardiac causes during the sleeping hours, which contrasts strikingly with the nadir of sudden death from cardiac causes during this period in people without obstructive sleep apnea and in the general population.

Retinal microvascular abnormalities and 10-year cardiovascular mortality: a population-based case-control study

PURPOSE

Retinal microvascular abnormalities reflect persistent arteriolar damage from hypertension and independently predict stroke. We examined their associations with long-term cardiovascular mortality.

DESIGN

Population-based, nested, case-control study.

POPULATION

Cases were Beaver Dam Eye Study participants (age range, 43-84 years) who died of coronary heart disease or stroke between the baseline examination in 1988 to 1990 and 1999 (n = 413). Nearly 3 controls per case were selected from the baseline cohort, frequency-matched on 5-year age intervals and gender (n = 1198).

METHODS

Retinal photographs of cases and controls at baseline were evaluated for retinopathy, focal arteriolar narrowing, and arteriovenous nicking by graders masked to case-control status using standardized protocols. To obtain an estimate of generalized arteriolar narrowing, photographs were digitized and diameters of individual retinal vessels were measured and summarized by a computer program.

MAIN OUTCOME MEASURE

Ten-year cardiovascular mortality.

RESULTS

After controlling for systolic blood pressure, diabetes, glycosylated hemoglobin levels, and other risk factors, retinopathy was associated with increased cardiovascular mortality, with odds ratios of 1.8 (95% confidence interval [CI], 1.2, 2.7). For other retinal abnormalities, associations with cardiovascular mortality were present only in younger people, with odds ratios of 2.7 (95% CI, 1.0, 7.4) for focal arteriolar narrowing, 1.8 (95% CI, 0.8, 4.5) for arteriovenous nicking, and 1.9 (95% CI, 1.2, 2.9) for generalized arteriolar narrowing in persons 43 to 74 years of age but odds ratios of 1.1, 0.4, and 1.0 for the corresponding retinal abnormalities in persons 75 years and older.

CONCLUSIONS

Retinopathy is independently associated with cardiovascular mortality. Associations for other retinal abnormalities were only observed in middle-aged persons. These data support recent studies that suggest retinal microvascular abnormalities provide independent information regarding cardiovascular risk.

Coronary disease surveillance in Olmsted County objectives and methodology

The community surveillance study of coronary heart disease (CHD) in Olmsted County, MN, is designed to estimate trends in myocardial infarction (MI) incidence, case fatality rate, and CHD mortality, while including all ages. A distinctive feature of this study is its ability to capture longitudinal data before and after index events via the medical record linkage system of the Rochester Epidemiology Project. The goal of this report is to describe the methods implemented to measure CHD trends, the implications of including elderly individuals on MI ascertainment and trends in prior CHD among persons with incident MI. The methods are based on standardized criteria involving the review of death certificate information and hospital records to identify CHD deaths, and incident MIs in Olmsted County. The medical record linkage system in place under the auspices of the Rochester Epidemiology Project was used to ascertain antecedent CHD and outcomes. Hospitalized MIs were screened from sampled events coded ICD9 codes 410-414 and classified using enzyme values, cardiac pain, and ECG coding. After screening 5,042 records, a cohort of 1,658 validated incident MIs was assembled 35% (575) among persons aged 75 years or greater. The proportion of MIs validated with cardiac pain and enzymes without Minnesota ECG coding was lower among the elderly than among persons less than 75 years of age (35 vs. 29%, respectively; P <.001). The proportion of events validated without requiring ECG coding decreased over time in both age strata (P for trend.001). Reliability analyses indicated excellent agreement in event classification. More than half of the incident MIs did not have antecedent CHD, and this proportion increased overtime. These data indicate that the elderly contribute approximately one-third of the cases of incident MI, underscoring the importance of including all ages to fully characterize the burden of CHD. Cases among elderly persons more frequently require ECG coding for validation, but standardized ascertainment procedures are feasible and reliable in all age groups. More than half of the incident MIs occurred among persons with no prior CHD, and this proportion increased over time. The combination of standardized methodology and of the longitudinal data via the record linkage system of the Rochester Epidemiology Project will allow reliable measures of CHD trends and help define preventive strategies.

Sudden cardiac death in the United States, 1989 to 1998

BACKGROUND

Sudden cardiac death (SCD) is a major clinical and public health problem.

METHODS AND RESULTS

United States (US) vital statistics mortality data from 1989 to 1998 were analyzed. SCD is defined as deaths occurring out of the hospital or in the emergency room or as "dead on arrival" with an underlying cause of death reported as a cardiac disease (ICD-9 code 390 to 398, 402, or 404 to 429). Death rates were calculated for residents of the US aged >/=35 years and standardized to the 2000 US population. Of 719 456 cardiac deaths among adults aged >/=35 years in 1998, 456 076 (63%) were defined as SCD. Among decedents aged 35 to 44 years, 74% of cardiac deaths were SCD. Of all SCDs in 1998, coronary heart disease (ICD-9 codes 410 to 414) was the underlying cause on 62% of death certificates. Death rates for SCD increased with age and were higher in men than women, although there was no difference at age >/=85 years. The black population had higher death rates for SCD than white, American Indian/Alaska Native, or Asian/Pacific Islander populations. The Hispanic population had lower death rates for SCD than the non-Hispanic population. From 1989 to 1998, SCD, as the proportion of all cardiac deaths, increased 12.4% (56.3% to 63.9%), and age-adjusted SCD rates declined 11.7% in men and 5.8% in women. During the same time, age-specific death rates for SCD increased 21% among women aged 35 to 44 years.

CONCLUSIONS

SCD remains an important public health problem in the US. The increase in death rates for SCD among younger women warrants additional investigation.

Trends in acute coronary heart disease mortality, morbidity, and medical care from 1985 through 1997: the Minnesota heart survey

BACKGROUND

Coronary heart disease (CHD) mortality continued to decline from 1985 to 1997.

METHODS AND RESULTS

We tabulated CHD deaths (ICD-9 codes 410 through 414) in the Minneapolis/St Paul, Minnesota, area. For 1985, 1990, and 1995, trained nurses abstracted the hospital records of patients 30 to 74 years old with a discharge diagnosis of acute CHD (ICD-9 codes 410 or 411). Acute myocardial infarction (AMI) events were validated and followed for 3-year all-cause mortality. Between 1985 and 1997, age-adjusted CHD mortality rates in Minneapolis/St Paul fell 47% and 51% in men and women, respectively; the comparable declines in US whites were 34% and 29%. In-hospital mortality declined faster than out-of-hospital mortality. The rate of AMI (ICD-9 code 410) hospital discharges declined almost 20% between 1985 and 1995, whereas the discharge rate for unstable angina (ICD-9 code 411) increased substantially. The incidence of hospitalized definite AMI declined approximately 10%, whereas recurrence rates fell 20% to 30%. Three-year case fatality rates after hospitalized AMI decreased consistently by 31% and 41% in men and women, respectively. In-hospital administration of thrombolytic therapy, emergency angioplasty, ACE inhibitors, beta-blockers, heparin, and aspirin increased greatly.

CONCLUSIONS

Declining out-of-hospital death rates, declining incidence and recurrence of AMI in the population, and marked improvements in the survival of AMI patients all contributed to the 1985 to 1997 decline of CHD mortality in the Minneapolis/St Paul metropolitan area. The effects of early and late medical care seem to have had the greatest contribution to rates during this time period.

Community-wide coronary heart disease mortality in Mexican Americans equals or exceeds that in non-Hispanic whites: the Corpus Christi Heart Project

PURPOSE

Previous comparisons of coronary heart disease mortality between Mexican Americans and non-Hispanic whites have given paradoxic results: despite their adverse cardiovascular risk profiles, especially a greater prevalence of diabetes, Mexican Americans are reported to have lower rates of mortality from coronary heart disease.

SUBJECTS AND METHODS

We performed a community-based surveillance among all residents of Nueces County, Texas, aged 25 to 74 years, from 1990 to 1994. All death certificates were obtained and coded, and deaths potentially related to coronary heart disease were selected and validated by standardized methods blinded to ethnicity. Validated in-hospital and out-of-hospital coronary heart disease mortality was compared between 785 Mexican Americans and 862 non-Hispanic white women and men.

RESULTS

Validated coronary heart disease mortality in Mexican Americans exceeded that for non-Hispanic whites in the same community. Among women, definite coronary heart disease mortality was 40% greater among Mexican Americans (rate ratio [RR] 1.43, 95% confidence interval [CI]: 1.12 to 1.82), as was all coronary heart disease mortality (RR, 1.32, 95% CI: 1.08 to 1.63). Among men, Mexican Americans had greater rates of all (RR, 1.11; 95% CI: 0.96 to 1.28) and definite coronary heart disease mortality (RR, 1.16; 95% CI: 0.91 to 1.47), but the associations were not statistically significant.

CONCLUSIONS

When community-wide mortality rates from coronary heart disease are properly validated, Mexican Americans have rates equal to or higher than those of non-Hispanic whites. Community-based surveillance with validation of coronary heart disease as the cause of death is necessary to avoid the errors that occur with the use of death certificates alone.

Validation of death certificate diagnosis for coronary heart disease: the Atherosclerosis Risk in Communities (ARIC) Study

The validity of the death certificate in identifying coronary heart disease deaths was evaluated using data from the community surveillance component of the Atherosclerosis Risk in Communities Study (ARIC). Deaths in the four ARIC communities of Forsyth Co., NC; Jackson, MS; Minneapolis, MN; and Washington Co., MD were selected based on underlying cause of death codes as determined by the rules of the ninth revision of the International Classification of Diseases (ICD-9). Information about the deaths was gathered through informant interviews, physician or coroner questionnaires, and medical record abstraction, and was used to validate the cause of death. Sensitivity, specificity, and positive predictive value of the death certificate classification of CHD death (ICD-9 codes 410-414 and 429.2) were estimated by comparison with the validated cause of death based on physician review of all available information. Results from 9 years of surveillance included a positive predictive value 0.67 (95% CI 0.66-0.68), sensitivity of 0.81 (95% CI 0.79-0.83), and a false-positive rate (1-specificity) of 0.28 (95% CI 0.26-0.30). Comparing CHD deaths as defined by the death certificate with validated CHD deaths indicated that the death certificate overestimated CHD mortality by approximately 20% in the ARIC communities. Within subgroups, death certificate overestimation was reduced with advancing age (up to age 74), was consistent over time, was not dependent on gender, and exhibited considerable variation among communities.

Mortality impact of an integrated community cardiovascular health program

BACKGROUND

Preventing cardiovascular disease through community interventions makes theoretical sense but has been difficult to demonstrate. We set out to determine whether a community cardiovascular health program had an impact on mortality.

DESIGN

Program evaluation plus ecologic observational analysis of program encounters and mortality rates with external comparisons.

SETTING

Franklin County and two comparison counties in rural Maine.

PARTICIPANTS

Program encountered >50% of regional adults, broadly distributed by site, gender, and age.

INTERVENTIONS

From 1974 to 1994, a community program, integrated with primary medical care and staffed by professional nurses, provided education, screening, counseling, referral, tracking, and follow-up for cardiovascular risk factors.

MAIN OUTCOME MEASURES

Age-adjusted mortality rates (total, heart, coronary, cerebrovascular, cancer) for three counties and Maine, plus annual program encounters.

RESULTS

Relative to Maine, the Franklin heart disease death rate was 0.97 at baseline (1960-1969; 95% confidence interval, 0.91 to 1.03), 0.91 during the program (0.85 to 0.97), 0.83 during the 11 years of program growth (0.78 to 0.88), but 1.0 during the 10 years of decreasing encounters. Franklin's total death rate was 1.01 at baseline, 0.95 during the program (0.92 to 0.98), and 0.90 during program growth (0.86 to 0. 94). Results were similar for coronary disease, stroke, and cancer. Relative death rates did not fall in either comparison county. Nurse-client encounters totaled 120,280 over 21 years. Relative to Maine, heart disease death rates correlated inversely with program encounters (r = -0.53) but not with unemployment or physician supply.

CONCLUSIONS

Integrated with primary medical care, a comprehensive, nurse-mediated community cardiovascular health program in rural Maine has been associated with significant time-dependent and dose-dependent reductions in cardiovascular and total mortality.

Validation of death certificate diagnosis of out-of-hospital coronary heart disease deaths in Olmsted County, Minnesota

OBJECTIVE

To evaluate the validity of death certificate diagnosis of out-of-hospital (OOH) coronary heart disease (CHD) and sudden cardiac death (SCD) in Olmsted County, Minnesota, between 1981 and 1994.

METHODS

In this review of the medical records, autopsy reports, and coroner's files, OOH deaths with heart disease as the underlying cause of death on the death certificate were classified into CHD (International Classification of Diseases, 9th Revision, Clinical Modification [ICD-9-CM] codes 410-414) and non-CHD (other ICD-9-CM heart disease codes) deaths. A 10% random sample (n = 174) of these death certificates was reviewed by physicians, and published validation criteria were applied to classify these deaths into validated CHD or non-CHD categories. Sudden cardiac death was defined as validated CHD that occurred at an OOH location with less than 24 hours between symptom onset and death.

RESULTS

The death certificate definition of OOH CHD death (ICD-9-CM codes 410-414) had high sensitivity and positive predictive value of 91% and 96%, respectively. The specificity and the negative predictive value were slightly lower at 86% and 72%, respectively. The sensitivity of death certificate diagnosis of CHD for validated SCD was 89%, and the positive predictive value was 77%. Using a more restrictive definition of SCD, that is, less than 1 hour between the onset of symptoms and death, the positive predictive value of CHD codes for SCD was lower at 52%.

CONCLUSIONS

In Olmsted County, the positive predictive values of death certificate diagnosis for OOH CHD and SCD are high. Relying on death certificate diagnoses results in about 5% underestimation of the true CHD rates, whereas their use as a surrogate for SCD yields a 16% overestimation of the true SCD rates.

Predicting sudden death in the population: the Paris Prospective Study I

BACKGROUND

Sudden death was found to share the same set of usual risk factors as coronary events and therefore could not be specifically predicted in the population. It appears, however, that parental history of sudden death has not been investigated yet as a risk factor for sudden death. Therefore, we assessed risk factors, including parental sudden death, associated with the occurrence of sudden death in a long-term cohort study.

METHODS AND RESULTS

We included 7746 men employed by the city of Paris who were 43 to 52 years of age in 1967 to 1972 in the Paris Prospective Study I. Each subject underwent a physical examination and an ECG, provided blood for laboratory tests, and answered questionnaires administered by trained interviewers who paid particular attention to family medical history. Men with known ischemic cardiac disease were further excluded from analysis. For 95.5% of the men, vital status was obtained from specific inquiries until retirement, then by death certificates. Resting heart rate, systolic or diastolic blood pressure, tobacco consumption, body mass index, diabetes status, serum cholesterol, and parental history of sudden death were independent factors associated with sudden death during follow-up (23 years on average). When adjusted for confounding variables, including parental history of myocardial infarction, relative risk of sudden death associated with parental sudden death was 1.80 (95% CI, 1.11 to 2.88).

CONCLUSIONS

Parental sudden death is an independent risk factor for sudden death in middle-aged men. The existence of familial risk factors for sudden death may help provide better identification of subjects at high risk of and early prevention of sudden death.

The validity of the routine mortality statistics on coronary heart disease in Finland: comparison with the FINMONICA MI register data for the years 1983-1992. Finnish multinational MONItoring of trends and determinants in CArdiovascular disease

We compared the diagnoses obtained from the routine mortality statistics with the standardized World Health Organization (WHO) MONICA (multinational MONItoring of trends and determinants in CArdiovascular disease) classification in suspect coronary heart disease (CHD) deaths registered in the FINMONICA myocardial infarction (MI) register during 1983-1992. All CHD deaths from routine mortality statistics (International Classification of Diseases codes 410-414) were registered in the MI register. Of the CHD deaths in routine mortality statistics 1.7% in men and 4.8% in women did not fulfill the MONICA criteria for CHD death (P<0.001 for the difference between the sexes). In men 4.7% and in women 7.3% (P=0.004) of the deaths registered in the MI Register and classified as CHD deaths by MONICA criteria had another underlying cause of death than CHD in routine mortality statistics; this proportion increased over time in both sexes (P=0.002 in men and P=0.77 in women). The CHD mortality trends obtained separately from the routine mortality statistics and from the FINMONICA MI Register were very similar. In conclusion, the high CHD mortality in Finland reported by the routine mortality statistics is real. It is possible that some CHD deaths have escaped registration, but the decline seen in the CHD mortality is also real.

Validation of death certificate diagnosis of out-of-hospital sudden cardiac death

The validity of death certificate diagnosis of out-of-hospital sudden cardiac death (OOH-SCD) was studied among 108,676 30- to 74-year-old residents in 5 Minnesota communities using 6-year mortality data (1985 to 1990). Among 4,244 total deaths, location of death was listed on the certificate as out of hospital in 2,035 cases. Of those, 911 were judged not to have OOH-SCD because they had actually been admitted to the hospital or were noncardiovascular deaths. Among the remaining 1,124, 254 were diagnosed as OOH-SCD using a thorough, physician-based procedure that used clinical records, autopsy reports, and an informant (next-of-kin) interview. We used only death certificate information to define OOH-SCD simply and inexpensively as ICD-9 code 427.5 (cardiac arrest) plus location of death listed as out-of-hospital. Compared with the physician diagnosis, sensitivity was only 24%, whereas specificity was 85%. When the definition of OOH-SCD was expanded to include ICD codes 410-414 (acute myocardial infarction and chronic coronary artery disease), sensitivity improved to 87%, whereas specificity became 66%. However, even with this higher sensitivity and specificity, only 27% of the cases labeled OOH-SCD by death certificate agreed with the physician diagnosis. Death certificate diagnosis of OOH-SCD included many erroneous cases, and may not have been suitable for study of etiologic factors, such as cardiac dysrhythmias. Death certificate diagnosis may be useful to assess population time trends in OOH-SCD, provided that misclassification (false-positive rate) remains constant over time.

[Mortality trends for acute rheumatic fever and chronic rheumatic heart disease in Venezuela, 1955-1994]

This study reports on deaths due to acute rheumatic fever (ARF) and chronic rheumatic heart disease (CRHD) in Venezuela from 1955 to 1994. Census publications and other official sources provide the population data. Yearly age -and sex- specific mortality rates per 100,000 inhabitants were calculated and adjusted by the direct method to the WHO's standard population. The RF-adjusted mortality rate (AMR) declined: total from 7.68 to 1.08 (-85.9%); male from 7.53 to 0.84 (-88.8%); and female from 7.83 to 1.33 (-83.0%). In all cases female RF-AMRs were higher than male. There was a reduction of 88.5% in the ratio of RF deaths to cardiovascular deaths (ICD-6330-334,400-447; ICD-7330-334,400-447; ICD-8 390-438; ICD-9 390-438). ARF-AMR declined (-93.5%) as did CRHD-AMR (-85.1%). Proportional death by ARF and CRHD in patients 45 years old and younger increased. Venezuela experienced a continuous decline in RF-AMR from 1955 to the l980s, followed by a period of stabilization lasting until l994. The reduction could be the consequence of improvement in socioeconomic status and of RF prevention with penicillin, a standard practice in the health care system. The 1980s and 1990s RF-AMR stabilization could be associated with economic setbacks in Venezuela and changes in the agent's virulence patterns.

Use and accuracy of state death certificates for classification of sudden cardiac deaths in high-risk populations

In a large cohort of patients with known or suspected coronary disease, we evaluated the characteristics of 407 patients who died after hospital discharge and tested whether the state death certificate can be used to classify deaths as sudden cardiac versus nonsudden. Compared with a paramedic classification system based on heart rhythm, the death certificate-based classification resulted in a sensitivity that ranged from 78% to 85% and a specificity that ranged from 25% to 58%. We conclude that the death certificate can be used to identify cases of sudden cardiac death in patients at high risk; however, there is a substantial rate of false-positive sudden death classification.

[Validation of "myocardial infarction" as cause of death on death certificates in Barquisimeto, Lara state, Venezuela]

Death rates due to Ischemic Heart Disease (IHD) are widely used to assess regional and national cardiovascular health status. However, their validity is questionable, essentially because they are based on death certificates (DCs). The present study was conducted in the Greater Metropolitan Area of Barquisimeto (Lara State, Venezuela), from June 1991 to July 1992. The purpose was to establish the validity of the diagnosis of myocardial infarction in DCs of intrahospital deaths. Efforts were made to locate all clinical charts and any other relevant information. To validate the diagnosis of MI in the DC we used the MONICA project criteria. During the study period a total of 247 eligible DCs were recorded. Sufficient clinical information was located for 136 cases (55%). The results were as follows: definite MI - 62 cases (45.6%); probable MI - 31 cases (22.8%); and non MI - 43 cases (31.6%). These results may indicate an overestimation of MI death rates of about 32% [95% Confidence Interval = 23.8% - 39.4%]. Since these data are from a region with an organized cardiovascular health system, it is expected that the overestimation for the rest of the country may be even higher. Thus, in order to enhance quality and accuracy of DCs, it is necessary to develop a system to improve adherence to existing norms for filling out and processing such forms.

Race differences in estimates of sudden coronary heart disease mortality, 1980-1988: the impact of ill-defined death

Coronary heart disease (CHD) deaths occurring outside of hospitals or in emergency rooms (OH/ER) have been used to estimate sudden CHD mortality. This study quantifies the potential impact of natural deaths coded to an unspecified cause on race differences in sudden CHD estimates, during 1980-1988. Death certificate data for OH/ER deaths in 40 U.S. states were used to create annual age-adjusted rates for sudden CHD and sudden CHD rates revised to include deaths with an unspecified cause (ICD9, 780-799). Revising the mortality rates to include unspecified deaths results in greater racial disparities for estimates of sudden CHD. In 1980, black-white race differences went from 89 to 128 and 103 to 121 (per 100,000) for men and women, respectively, with revision. Among blacks, revised sudden CHD mortality declined approximately 22%, during 1980-1988, compared to 10% for unrevised sudden CHD; with no observed effect of revision on percent declines among whites. Previous studies may have underestimated declines in racial disparities of sudden CHD, due to improved quality of OH/ER death certification among blacks. Improved access to routine and emergency medical care, through increased affordability and greater availability, may be important to address higher OH/ER CHD among blacks.

Recent trends in acute coronary heart disease--mortality, morbidity, medical care, and risk factors. The Minnesota Heart Survey Investigators

BACKGROUND

Mortality from coronary heart disease (CHD) has declined in the United States since the late 1960s. To understand the reasons for the decline during the period form 1985 to 1990, we examined trends in mortality and morbidity due to CHD, medical care, and risk factors for CHD in a large metropolitan population.

METHODS

We identified all deaths from CHD in residents of the Minneapolis-St. Paul, Minnesota, metropolitan area who were 30 to 74 years old and classified the deaths according to whether they occurred in or out of the hospital. For 1985 and 1990, we obtained lists of patients in this age range who were discharged with a diagnosis of acute CHD from all area hospitals, and we selected the medical records of 50 percent of these patients for abstraction. Definite myocardial infarctions were identified with standardized diagnostic algorithm. The 1985 and 1990 cohorts of patients hospitalized for myocardial infarction were followed for at least three years to identify those who died from any cause. Trends in risk factors for CHD were investigated through surveys of 25-to-74-year-olds that were conducted in 1985 through 1987 and 1990 through 1992.

RESULTS

Between 1985 and 1990, mortality from CHD fell by 25 percent for both men and women, and the decline in in-hospital mortality (41 percent) exceeded the decline in out-of-hospital mortality (17 percent) among men. The rates of hospitalization for acute myocardial infarction declined slightly, by 5 to 10 percent, between 1985 and 1990. Survival among patients hospitalized for acute myocardial infarction increased substantially during that period. After adjustment for age and previous myocardial infarction, the relative risk of dying within three years of hospitalization for a myocardial infarction (for the 1990 cohort as compared with the 1985 cohort) was 0.76 for men (95 percent confidence interval, 0.65 to 0.89) and 0.84 for women (95 percent confidence interval, 0.71 to 1.00). Substantial increases in the use of thrombolytic therapy, heparin, aspirin, and coronary angioplasty paralleled the survival trends. In general, the risk-factor profile of the area population with respect to CHD also improved considerably during that time.

CONCLUSIONS

The recent decline in mortality due to CHD in the Minneapolis-St. Paul metropolitan area can be explained by both the declining incidence of myocardial infarction in the population and the improved survival of patients with myocardial infarction.

Challenges in cardiac arrest research: data collection to assess outcomes

To enhance comparability in reports on survival from out-of-hospital cardiac arrest, an international task force recently developed a set of guidelines for uniform terminology, definitions, and data collection for outcome research on cardiac arrest--the Utstein style. Because the data collection recommended is limited to information available through emergency medical services systems, the potential for bias in comparisons of cardiac arrest outcomes remains. By expanding data collection to include the identification of all cases of cardiac arrest in the community, including patients who do not present for care by an emergency medical services system, a population-based approach can be achieved. We review the strengths and limitations of both emergency medical services-based and population-based data collection to assess outcomes of cardiac arrest, outline practical steps required to implement a population-based approach, and suggest that extension of the Utstein style guidelines to include all cardiac arrest cases within a defined population is needed to minimize potential bias in comparisons of cardiac arrest outcomes across communities or over time.

Risk factors for coronary heart disease mortality among persons with diabetes

Although coronary heart disease is a leading cause of morbidity and mortality among persons with diabetes, the risk factors for coronary heart disease have not been well established for this population. The authors performed a case-control analysis by using data from two large population-based surveys. Cases of persons who died of coronary heart disease were identified from the 1986 National Mortality Followback Survey, and controls were taken from behavioral risk factor surveys conducted in 35 states in 1988. Diabetic women younger than 55 years with no other risk factors for coronary heart disease had a 16-fold higher risk of dying from coronary heart disease than did women without diabetes. About one-third of younger women who died of coronary heart disease had diabetes. Diabetic men less than 45 years old with no other risk factors for coronary heart disease had an eightfold higher risk of coronary heart disease mortality. Among older white men and women, diabetes increased the risk of mortality from coronary heart disease about twofold. In younger diabetics, current cigarette smoking was associated with a 50% increase in risk, and high blood pressure increased the risk more than threefold. In the older age group, risk factors for coronary heart disease mortality were similar among those with and those without diabetes: Cigarette smoking and high blood pressure each were associated with about a twofold increase in risk. Diabetes is a particularly strong risk factor for mortality from coronary heart disease in young adults. Smoking and blood pressure control represent major opportunities to reduce the risk of coronary heart disease among persons with diabetes.

Recording of deaths in hospital information systems: implications for audit and outcome studies

STUDY OBJECTIVE

The aim was to report on the extent to which death certificates which specify that death occurred in hospital can be matched and linked with routine hospital inpatient information systems.

DESIGN

The study involved linkage of hospital records which specified that death occurred in hospital to corresponding death certificates; and linkage of death certificates which specified that death occurred in hospital to corresponding hospital records.

SETTING

Six health districts in southern England covered by medical record linkage.

SUBJECTS

Records were examined of patients aged 65 years and over, which specified that death occurred in hospital between 1979 and 1985.

MAIN RESULTS

98.2% of hospital record abstracts which specified that death occurred in hospital were linked by our standard computer-based techniques to death certificates. Conversely, however, only 94.4% of death certificates which specified that death occurred in hospital could be linked to the abstracts of corresponding hospital inpatient records. A major factor contributing to the latter failures may be a difference of definition of what constitutes a death "following hospital admission" in patients who die shortly after arrival at hospital.

CONCLUSIONS

Linkage of hospital records to death certificates is both feasible and desirable. Error rates are generally small; but hospital inpatient record abstracts corresponding to death certificates for deaths in hospital may not invariably exist when death occurs shortly after the arrival of the patient at hospital.

Causes of death in a cohort of 50,465 young men--validity of recorded suicide as underlying cause of death

We studied causes of death in a cohort of all young males (n = 50,465) conscripted for military service in 1969-70. Six hundred eighty three deaths occurred in the cohort during the follow-up through 1983. Injury-related deaths accounted for 75% of all deaths. Of these, 38% were definite suicides, 10% undetermined suicides and 30% motor vehicle accidents. The validity of officially recorded causes of death was studied by scrutinizing all death certificates (n = 683) and forensic reports, including police reports, toxicological and histological data, from a sample (n = 322) of deaths with unclear circumstances. Of 161 officially recorded suicides (E950-959), only one case was reevaluated into poisoning, "undetermined" (E980). Of 47 cases officially recorded "undetermined" (E980-989), 9 were reevaluated into definite suicide (E950-959) although we believe that this is still an underestimation of "true" suicide cases. An alcohol concentration of more than 0.1 g% was found in 45% of all violent deaths (E800-999), 34% of all suicides and 60% of all "undetermined" deaths. We conclude that the causes of death in most cases of injury related death in young age are recorded with high accuracy. Reevaluation of recorded deaths from "undetermined" causes revealed a number of definite suicides, although the "true" number of suicides is difficult to assess even after close scrutiny of the information available.

An approach to several problems in using large databases for population-based case-control studies of the therapeutic efficacy and safety of anti-hypertensive medicines

In this paper we discuss approaches to two distinct problems in using large computerized databases to conduct population-based case-control studies. The first topic, concerning case ascertainment, is a methodologic problem, and the second, concerning confounding by indication, is an analytic problem. The first involves attempting to ascertain all incident cases of coronary disease among enrollees of Group Health Cooperative of Puget Sound (GHC), a large health-maintenance organization. Methodologic studies reported here have helped us improve the efficiency of using the large computerized databases for case ascertainment at GHC. The second problem involves the issue of confounding by drug indication. Drugs such as beta-blockers have multiple indications, including the treatment of both high blood pressure and angina. These two indications may make it difficult in an observational study to determine whether beta-blockers may prevent coronary disease in patients with high blood pressure. We discuss here our current thinking about the best analytic approach to this problem.

Geographic variation in sudden coronary death

To describe geographic variations in an indicator of sudden coronary death, data from the National Center for Health Statistics were examined for deaths occurring out of hospital or in emergency rooms in 1984 to 1986 in 42 states. In white males aged 55 to 64 years, the percent of ischemic heart disease deaths coded as occurring out of hospital or in the ER ranged from 49.6% to 70.4%. The percents tended to be higher in mountain states and around Lake Michigan. However, neighboring states sometimes had very different percents. Within regions, percents were higher in nonmetropolitan than in metropolitan areas. Standard mortality ratios for white males of all ages revealed that several states had relatively high rates of death out of hospital or in the ER. These included New York, Michigan, and Wisconsin. High rates of coronary death out of hospital or in the ER may be due to high overall coronary death rates, high percent of coronary deaths occurring out of hospital or in the ER, or both. Further studies are needed of geographic variation in sudden coronary death and cardiac arrest and factors that might explain the variation such as emergency medical services. Place of death data from death certificates may be useful in monitoring efforts to prevent sudden coronary death.

[Mortality analysis: when is single evaluation of the basic cause of death allowable, when should multi-causality be assessed?]

Data quality is often a critical point in mortality studies. The purpose of the present report is to present criteria for assessing the value of death-certificate-based mortality studies. For this purpose all 57,454 Swiss death certificates of the year 1979 were analysed. Reliability of the diagnosis listed on the death certificate was investigated by comparing for each case of a linked sample of 12,478 deaths the cause of death with medical information available from the hospital record. Retrieval rates (percentage of cases for which the given diagnosis appears in both registries) were calculated for the primary diagnoses named in each data set. These can be considered as measures of reliability of diagnoses. The graphs given indicate a high reliability for cancers and accidents. Reliability was lower for other causes of death such as cardiovascular diseases, diabetes mellitus, rheumatic diseases. Restriction to the primary cause of death can be accepted for most cancers, accidents and violent deaths. For other causes of death, decisions must be made individually and multicausal analysis may be indicated. In addition, knowledge of the reliability of the diagnoses of interest is necessary for the interpretation of results derived from death certificate-based mortality studies.

Sudden coronary death in the United States: 1980-1985

To describe patterns of an indicator of sudden coronary death, data from the National Center for Health Statistics were examined for deaths occurring out of hospital and in the emergency room (OH/ER) from 1980 to 1985 in 40 states. In 1985, 56% of ischemic heart disease deaths occurred OH/ER among persons aged 35-74 years. The percentage occurring OH/ER declined with age, was higher in men than women, and higher in blacks than whites. At age 55-64, 61% of ischemic heart disease deaths in white and 66% in black men occurred OH/ER. Between 1980 and 1985, age-adjusted death rates in white men aged 35-74 years declined 19% for OH/ER and 18% for in-hospital ischemic heart disease deaths. The percentage of deaths in ER increased. The decline in deaths occurring OH/ER accounted for 61% of the total absolute decline in ischemic heart disease death rate in white men, 55% in white women, and about 70% in nonwhites. The decline in rates of death OH/ER should encourage further efforts at preventing coronary heart disease and improving emergency medical services.