Multiple cause-of-death data as a tool for detecting artificial trends in the underlying cause statistics: a methodological study

The aims of the study were: (i) to identify trends in the underlying cause-of-death statistics that are due to changes in the coders' selection and coding of causes, and (ii) to identify changes in the coders' documented registration principles that can explain the observed trends in the statistics. 31 Basic Tabulation List categories from the Swedish national cause-of-death register for 1970-1988 were studied. The coders' tendency to register a condition as the underlying cause of death (the underlying cause ratio) was estimated by dividing the occurrence of the condition as underlying cause (the underlying cause rate) with the total registration of the condition (the multiple cause rate). When the development of the underlying cause rate series followed more closely the underlying cause ratio series than the multiple cause rate series, and a corresponding change in the registration rules could be found, the underlying cause rate trend was concluded to be due to changes in the coders' tendency to register the condition. For thirteen categories (fourteen trends), the trends could be explained by changes in the coders' interpretation practice: five upward, four insignificant, and five downward trends. In addition, for three categories the trends could be explained by new explicit ICD-9 rules.     

Participation of NK1.1+ T cells in the rejection of lpr alphabetaT cells when bone marrow cells of lpr mice are transplanted into B6 mice

BACKGROUND: Cause-of-death statistics are widely used for comparing health characteristics of European Community (EC) countries. Before attempting to interpret between-country differences, it is essential to assess the biases affecting the comparability of the data. EUROSTAT decided to address globally this problem with the objective to improve the quality and comparability of cause-of-death data within the EC. METHODS: The material is based on a review of results of international comparative cause-of-death studies and on specific inquiries among EC. Both cause-of-death certification and codification practices are analysed. Certification is studied comparing the models of death certificates, the type of information captured, certifiers training and querying practices. The different coding systems are analysed (International classification of diseases (ICD) in use, interpretation of the ICD rules, implementation of automated coding systems). RESULTS: International studies on comparability of certification and coding practices between countries are rare. These studies are based on certification of cases histories and recoding of samples of death certificates. Recent studies on respiratory diseases, cancers and diabetes outline differences that influenced on the reported level of mortality. The specific EUROSTAT investigation (1997) outline general discrepancies: models of death certificates, nature and amount of information entered, way to establish the diagnosis, degree of consistency of the certification process, autopsy practices, certifiers practices, implementation of ICD-10 and implementation of automated coding systems. CONCLUSION: EUROSTAT studies are now focused on causes of death requiring special attention for comparability (e.g. suicide, accidental deaths, drug and alcohol related deaths, unknown and ill-defined causes), on procedures to improve the homogeneity of certifiers training and querying practices, on the effect of the transition to ICD-10. The international model of death certificate recommended by the World Health Organization should be adopted as widely as possible. Uniform complementary information (e.g. surgery, pregnancy, autopsy, place of occurrence of accidental deaths, work accident) should also be adopted. The EUROSTAT investigations must result in definitions of common recommendations and guidelines to EC.     

The main causes of death in Spain, 1992; comment

BACKGROUND: To study the mortality from the leading causes of death in Spain in 1992 and trends since 1980. POPULATION AND METHOD: The number of deaths was obtained from mortality statistics. We included the 12 causes with the highest mortality rates in 1992 and calculated for each cause of death the age adjusted mortality rates for each year in the study period, the percent change from 1990 to 1992 and from 1980 to 1992, and the adjusted ratio of rates between men and women in 1992. RESULTS: The leading causes of death in 1992 were malignant neoplasms, with 24.3% of deaths and a mortality rate of 205.6 per 100,000 population; diseases of the heart, with 22.6% and a rate of 191.8 per 100,000; and cerebrovascular disease, with 12.7% and a rate of 107.6 per 100,000 population. Between 1980 and 1992 the adjusted mortality rate increased for four causes of death: malignant neoplasms; chronic obstructive pulmonary disease and similar diseases; nephritis, nephrotic syndrome and nephrosis; and suicide. From 1990 to 1992, the adjusted mortality rate declined for all other causes of death. From 1990 to 1992, the adjusted mortality rate declined for all causes of death except for malignant neoplasms and human immunodeficiency virus (HIV) infection, which rose 0.4% and 69%, respectively. The adjusted mortality rate was higher in men than in women for all causes of death except for diabetes mellitus and atherosclerosis. CONCLUSIONS: Except for malignant neoplasms and HIV infection, mortality from all other leading causes of death declined in 1992 with respect to 1990, independently of the trend experienced by each cause of death in the eighties.     

Evolving trends revealed by autopsies of patients with the acquired immunodeficiency syndrome. 565 autopsies in adults with the acquired immunodeficiency syndrome, Los Angeles, Calif, 1982-1993 [corrected

OBJECTIVE: To determine changes in causes of death, survival, and organ system distribution of major opportunistic infections and neoplasms in adults dying with the acquired immunodeficiency syndrome (AIDS) following the widespread use of antiretroviral therapy and prophylaxis for opportunistic infections since 1988. DESIGN: A retrospective review of autopsy records with gross and microscopic pathologic findings, laboratory data, and clinical histories in cases of AIDS, comparing findings from 1982 through 1988 with those from 1989 through May 1993. SETTING: All autopsies were performed on persons dying in the metropolitan Los Angeles, Calif, area from January 1982 through May 1993. RESULTS: In 565 adult cases of AIDS at autopsy, Pneumocystis carinii pneumonia (PCP) remained the most common cause of death, but both the frequency of and number of deaths of PCP declined over time. Deaths from bacterial sepsis, cytomegalovirus infection, Mycobacterium avium complex infection, and toxoplasmosis also declined during this period, but mortality from fungal infections, tuberculosis, encephalopathy, and causes unrelated to AIDS increased. The death rate from malignant lymphoma remained high. Kaposi's sarcoma (KS) continued to occur more frequently in patients whose risk factor for human immunodeficiency virus infection (HIV) was homosexuality or bisexuality, but the death rate from KS was greatest for patients with a risk factor of blood exposure to HIV. Survival was shorter and deaths from tuberculosis more common in patients with a history of intravenous drug use. Overall survival of patients in other AIDS risk groups increased over time, particularly in those treated with antiretroviral therapy. The organ system distribution of major opportunistic infections and neoplasms was similar throughout the years of the study. The lung was the most frequent organ involved by AIDS-associated diseases leading to death, followed by the gastrointestinal tract and the central nervous system. CONCLUSIONS: The causes of death in AIDS have evolved since 1988 following the widespread use of prophylactic and antiretroviral therapies in patients with HIV infection. This has occurred primarily from changes in overall frequency and death rates from infections. Organ system involvement by AIDS-associated diseases has not changed significantly over time.     

Accuracy of mortality data for interstitial lung diseases in New Mexico, USA

BACKGROUND: The sensitivity and accuracy of death certificates and mortality data as sources of population based data on the occurrence of interstitial lung diseases has received limited attention. To determine the usefulness of these data sources, death certificates and mortality data from patients in New Mexico were examined. METHODS: Patients with an interstitial lung disease were identified from a population based registry. For subjects who had died, diagnostic information from their death certificates and from mortality data was compared with the clinical diagnoses made before death. RESULTS: Of 385 patients with a clinical diagnosis of an interstitial lung disease, 134 died between October 1988 and August 1994. Death certificates were obtained for 96% of these patients. An interstitial lung disease was listed somewhere on the death certificate for only 46% of the patients, and as an immediate cause of death for only 15%. For the patients with an interstitial lung disease listed somewhere on the death certificate the overall concordance between the diagnoses before death and those on the death certificate was 76%. Mortality data for the State of New Mexico showed a diagnosis of interstitial lung disease to be the assigned cause of death for only 22% of the patients. The overall agreement between the diagnoses made before death and those of the state mortality data was only 21%. CONCLUSIONS: These results suggest that death certificates and state mortality data are neither sensitive nor accurate for describing the occurrence of interstitial lung diseases. This finding may partly explain the apparently low mortality rates from idiopathic pulmonary fibrosis in the USA compared with other countries.     

Clinical features, molecular genetics, and pathophysiology of dominant optic atrophy

CONTEXT: Russian life expectancy has fallen sharply in the 1990s, but the impact of the major causes of death on that decline has not been measured. OBJECTIVE: To assess the contribution of selected causes of death to the dramatic decline in life expectancy in Russia in the years following the breakup of the Soviet Union. DESIGN: Mortality and natality data from the vital statistics systems of Russia and the United States. SETTING: Russia, 1990-1994. POPULATION: Entire population of Russia. MAIN OUTCOME VARIABLES: Mortality rates, life expectancy, and contribution to change in life expectancy. METHODS: Application of standard life-table methods to calculate life expectancy by year, and a partitioning method to assess the contribution of specific causes of death and age groups to the overall decline in life expectancy. United States data presented for comparative purposes. RESULTS: Age-adjusted mortality in Russia rose by almost 33% between 1990 and 1994. During that period, life expectancy for Russian men and women declined dramatically from 63.8 and 74.4 years to 57.7 and 71.2 years, respectively, while in the United States, life expectancy increased for both men and women from 71.8 and 78.8 years to 72.4 and 79.0 years, respectively. More than 75% of the decline in life expectancy was due to increased mortality rates for ages 25 to 64 years. Overall, cardiovascular diseases (heart disease and stroke) and injuries accounted for 65% of the decline in life expectancy while infectious diseases, including pneumonia and influenza, accounted for 5.8%, chronic liver diseases and cirrhosis for 2.4%, other alcohol-related causes for 9.6%, and cancer for 0.7%. Increases in cardiovascular mortality accounted for 41.6% of the decline in life expectancy for women and 33.4% for men, while increases in mortality from injuries (eg, falls, occupational injuries, motor vehicle crashes, suicides, and homicides) accounted for 32.8% of the decline in life expectancy for men and 21.8% for women. CONCLUSION: The striking rise in Russian mortality is beyond the peacetime experience of industrialized countries, with a 5-year decline in life expectancy in 4 years' time. Many factors appear to be operating simultaneously, including economic and social instability, high rates of tobacco and alcohol consumption, poor nutrition, depression, and deterioration of the health care system. Problems in data quality and reporting appear unable to account for these findings. These results clearly demonstrate that major declines in health and life expectancy can take place rapidly.     

Accuracy of death certificates for coding coronary heart disease as the cause of death

BACKGROUND: Death certificates are widely used in epidemiologic and clinical investigations and for national statistics. OBJECTIVE: To examine the accuracy of death certificates for coding coronary heart disease as the underlying cause of death. DESIGN: Community-based inception cohort followed since 1948. SETTING: Framingham, Massachusetts. PATIENTS: 2683 deceased Framingham Heart Study participants. MEASUREMENTS: Sensitivity, specificity, and predictive values of the death certificate. The reference standard was cause of death adjudicated by a panel of three physicians. RESULTS: Among 2683 decedents, the death certificate coded coronary heart disease as the underlying cause of death for 942; the physician panel assigned coronary heart disease for 758. The death certificate had a sensitivity of 83.8% (95% CI, 81.1 % to 86.4%), positive predictive value of 67.4% (CI, 64.4% to 70.4%), specificity of 84.1% (CI, 82.4% to 85.7%), and negative predictive value of 92.9% (CI, 91.7% to 94.1%) for coronary heart disease. The death certificate assigned coronary heart disease in 51.2% of 242 deaths (9.0% of total deaths) for which the physician panel could not determine a cause. Compared with the physician panel, the death certificate attributed 24.3% more deaths to coronary heart disease overall and more than twice as many deaths to coronary heart disease in decedents who were at least 85 years of age. When deaths that were assigned unknown cause by the physician panel were excluded, the death certificate still assigned more deaths to coronary heart disease (7.9% overall and 43.1% in the oldest age group). CONCLUSIONS: Coronary heart disease may be overrepresented as a cause of death on death certificates. National mortality statistics, which are based on death certificate data, may overestimate the frequency of coronary heart disease by 7.9% to 24.3% overall and by as much as two-fold in older persons.     

Repeated neonatal deaths in families with special reference to causes of death

It is recognized that one infant death in a family indicates an increased risk of death of a subsequent sibling. This study examines which cause of death of a sibling is related to the mortality of the younger sibling and when. Longitudinal vital events data from the maternal and child health and family planning (MCH-FP) project and the comparison areas in Matlab, Bangladesh, were used. Primary causes of 868 neonatal deaths and 624 post-neonatal deaths resulting from 18,865 singleton live births in 1989-92 and those (967 as neonates and 708 as post-neonates) of their immediate elder siblings were categorised into infectious and non-infectious diseases. Multinomial logistic regression was used to estimate the risk of younger siblings dying in each age period from infectious and non-infectious diseases given the age and cause of deaths of older siblings and controlling for other biosocial correlates of infant mortality. A neonatal death of non-infectious causes in a family was twice as likely to be followed by another one occurring at the same age from similar causes compared with a surviving infant followed by a neonatal death from non-infectious causes. The MCH-FP project, though successful in reducing the risk of neonatal and post-neonatal mortality from infectious diseases, did not reduce the risk of dying from non-infectious diseases.     

An analysis of risk factors for withdrawal from dialysis before death

Withdrawal from dialysis has been a significant cause of mortality among dialysis patients, accounting for 6 to 22% of deaths. Since 1990, a new death notification form has allowed more detailed analyses of withdrawal from dialysis separate from causes of death. Using the U.S. Renal Data System data base, this study examined 116,829 deaths in adult patients from 1990 to 1995. Adjusted odds ratios were calculated for the risk of withdrawal using logistic regression. Adjustments included age at death, ethnicity, gender, cause of death, primary cause of end-stage renal disease, time on dialysis, and dialysis modality. In addition, odds ratios of withdrawal were calculated for deaths in patients who started dialysis after age 65. Death was preceded by withdrawal significantly more frequently in women than in men, more than twice as frequently in Caucasians than in African-Americans or Asians, and more frequently in older than in younger age groups. Patients who died of chronic diseases (e.g., dementia, malignancy) were much more likely to withdraw before death, whereas patients who died from more acute causes (e.g., coronary artery disease) were less likely to withdraw before death. It is concluded that patients who are Caucasian, female, older, or die of chronic or progressive diseases are more likely to withdraw from dialysis before death. The ethnic and gender differences in withdrawal do not appear to have a medical explanation from this analysis. Further research along sociologic lines is needed to better explain the differences in withdrawal from chronic dialysis.     

Quality of the certification of death due to acute reaction to opiates and cocaine among inhabitants of the City of Madrid

BACKGROUND: Deaths by acute reaction from drugs consumption (RAD) particularly heroine or cocaine, collected in routine morality statistics, have not changed substantially during the last ten years, whereas an specific collection system (State Information System on Drug-Abuse SISD) presented a great increase. For this reason, we try to measure the validity of drug-related deaths certificate. METHODS: The cause of death, corresponding to the persons, from 15 to 39 years of age, decreased in 1988 and residing in the Municipality of Madrid, registered in the Civil Register Decease Book and in the death Statistics Bulletins (DSB) was compared with the cause present in the autopsy report. RESULTS: A detection rate of 2.45% for the CR and 3.27% for the DSB were obtained. With the consequent correction, the RAD for this age group would be the second cause of mortality in the Municipality of Madrid and deaths related to circulatory and respiratory system would decrease in a great measure. CONCLUSIONS: It is necessary to improve substantially the collection of this cause of death in mortality statistics if we want a correct measurement of drug abuse lethal effects and the effectiveness of control programmes on this health problem.     

Importance of heart failure as a cause of death. Changing contribution to overall mortality and coronary heart disease mortality in Scotland 1979-1992

AIMS: As heart failure is a syndrome arising from another condition, such as coronary heart disease, it is rarely officially coded as the underlying cause of death regardless of the cause recorded by the physician at the time of certification. We sought to assess the true contribution of heart failure to overall mortality and coronary heart disease mortality and to examine how this contribution has changed over time. METHODS AND RESULTS: We carried out a retrospective analysis of all death certificates in Scotland between 1979 and 1992 for which heart failure was coded as the underlying or a contributory cause of death. From a total of 833622 deaths in Scotland between 1979 and 1992, heart failure was coded as the underlying cause in only 1.5% (13695), but as a contributory cause in a further 14.3% (126073). In 1979, 28.5% of male and 40.4% of female deaths attributed to coronary heart disease (coded as the underlying cause of death) also had a coding for heart failure. In 1992 these percentages had risen significantly to 34.1% and 44.8%, respectively (both P<0.001). Mortality rates for heart failure as the underlying or contributory cause of death, standardized by age and sex, fell significantly over the period studied in all ages and in both sexes: by 31% in men and 41% in women <65 years and 15.8% in men and 5.1% in women > or =65 years, respectively (P<0.01 for all changes). CONCLUSIONS: Death from heart failure is substantially underestimated by official statistics. Furthermore, one third or more of deaths currently attributed to coronary heart disease may be related to heart failure and this proportion appears to be increasing. While the absolute numbers of deaths caused by heart failure remains constant, this study is the first to show that standardized mortality rates are declining.     

Mortality as a function of temperature. A study in Valencia, Spain, 1991-1993

BACKGROUND: Increased mortality is associated with both very low and very high ambient temperatures. This study assesses the relationship between daily numbers of deaths and variations in ambient temperature within the city of Valencia. METHODS: The daily number of deaths from all causes (total deaths and only those occurring in people aged over 70), as well as those deaths from specific causes (e.g. cardiovascular and respiratory diseases, malignant tumours and all causes except external ones) occurring within the city of Valencia were related to the average daily temperature using autoregressive Poisson regression controlling for seasonality, day of the week, holidays, air pollution, influenza incidence, and humidity. Temperature was measured within the regression model as two complementary variables: 'Heat' and 'Cold'; also taken into account were their delayed effects up to 2 weeks after measurement. RESULTS: Graphical analysis revealed a relationship between temperature and mortality according to the time of year. For the cooler months (November-April), the temperature at which mortality was lowest was the 'minimum' (i.e. around 15 degrees C), while for the warmer months (May-October), it occurred at around 24 degrees C. Because of this, a stratified analysis was undertaken with different values for the 'Heat' and 'Cold' variables according to which of the two seasons was involved. During the colder months of the year, higher temperatures tended to exert a rapid influence on mortality and the lower temperatures a more delayed relation. During the hot season it is the heat variable which more clearly manifests an effect, and this is prolonged over the two following weeks. Variations also occur according to age and cause of death. The effect of temperature is greater in persons aged over 70 years of age, and it is also greater in cases of circulatory and respiratory diseases. CONCLUSIONS: A statistically significant association has been found between temperature and mortality. This relationship is not monotonic, but mortality increases in proportion to the variance in ambient temperature from a range of temperatures that varies from winter to summer.     

The evolution of mortality in the first year of life in Spain (1975-1988)

In recent years, the rate of decline in infant mortality and the proportional mortality by some causes of death in the first year of life have had important changes. The objectives of this study are to describe such changes, and to suggest hypotheses about their meaning. Infant, early neonatal, late neonatal and postneonatal mortality rates from 1975 to 1988 were calculated with information from the death register. Also, several indicators of the trends of those rates and proportional mortality by "certain conditions originating in the perinatal period" have been calculated. The reduction in infant mortality was due, mainly, to early neonatal mortality, which had an annual average decline of 4.6% during the study period. The proportional mortality and the mortality rate by perinatal conditions in the postneonatal period increased between 1975 and 1988. The first increased from 1.3% to 5.2%, and the second from 0.07 to 0.15 per 1000 live births. Hypotheses about the meaning of these results are suggested, and some actions are proposed in order to monitor and conduct research on mortality during the first year of life.     

Pooled human immunoglobulins contain anti-idiotypes with reactivity against the SLE-associated 4B4 cross-reactive idiotype

Mortality among adolescents resident in the municipal district of Botucatu, State of S. Paulo, Brazil, according to age group (10 to 14 and 15 to 19 years), sex, occupation and cause of death, during the period from 1984 to 1993, was analysed. The mortality data were obtained from death certificates and the population estimates were based upon census figures. There was great variation in the mortality rates of the years studied. The mortality was greater among the males of the older age group (15 to 19 years), including both students and workers. There was predominance of external causes of mortality which suggests the need for further studies its determining factors. The data indicate that health programs targeted at regarding adolescents, their families and community should be developed since these are avoidable causes of death.     

Viral contamination of food products: a poorly understood public health problem

Throughout the world there have been several epidemics of food-borne diseases (FBD) about which there is lack of sufficient information for public health institutions to take appropriate measures. This study was conducted for the purpose of contributing to the dissemination of information on these diseases and their etiologic agents, epidemiology, and control. The study was based on data from 61 sources, including review articles, reports of outbreaks, and databases. Results reveal considerable underregistration and lack of data on FBD throughout the various countries, with viruses being the second most important cause of FBD in the United States of America. Two agents, Norwalk virus and hepatitis A virus, were the fifth and sixth most frequent causes, respectively, although the former was the single most frequent cause of FBD in 1982 and the second most frequent cause of water-borne diseases during the period from 1986 to 1988. Despite the scarcity of information on the problem, rotavirus, poliovirus, hepatitis E virus, astrovirus, and small gastroenteric viruses are also important causes of FBD. We also discuss the importance of viral zoonoses, especially hemorrhagic fevers transmitted by contact with rodent feces and tick-borne viral encephalitides (Lassa fever). There is discussion of the controversial mad cow disease and its potential transmission through food products, as well as of dietary aspects of the management of AIDS and other viral infections. Finally, measures for the prevention and control of FBD are described.     

Ten years of liver transplantation: an evolving understanding of late graft loss

BACKGROUND: We undertook this study to understand the causes of late graft loss and long-term outcome in orthotopic liver transplantation (OLT) recipients. METHODS: Prospectively collected data of 1174 consecutive OLT in 1045 adult patients who received liver grafts between April 1985 and August 1995 were reviewed. The causes of graft loss, pretransplant patient characteristics, and posttransplant events were analyzed in patients who survived at least 1 year after OLT, in an attempt to establish a link between these factors and graft loss. RESULTS: One hundred fifty-nine (17.9%) grafts were lost after the first year. Of these, 132 grafts were lost by death and 27 by retransplantation. Recipients who survived the first year (n=884) had 5- and 10-year survivals of 81.4% and 67.2%, respectively. Death with a functioning graft occurred in 97 (61%) patients. The main causes of late graft loss were recurrent disease (n=48), cardiovascular and cerebral vascular accidents (n=28), infections (n=24), and chronic rejection (n = 15). Pretransplant heart disease and diabetes were found to be significant risk factors for late graft loss due to cardiovascular diseases and cerebral vascular accidents. CONCLUSIONS: Survival of OLT patients who live beyond the first posttransplant year is excellent. Some patient characteristics may be associated with late graft loss. Compared with previous reports, this study shows an increased incidence of late graft loss secondary to recurrent diseases, de novo malignancies, cardiovascular diseases, and cerebral vascular accidents. Chronic rejection seems to be a less frequent cause of late graft loss. The prevention of recurrent disease and better immunosuppression may further improve these results.     

Mortality among fire fighters in metropolitan Toronto

Fire fighters are exposed to substances which are recognized or suspected causal agents in cancer or heart disease. The purpose of this study was to determine whether or not fire fighters experience increased risk for any specific cause of death. A retrospective cohort study was conducted, with 5,995 subjects recruited from all six fire departments within Metropolitan Toronto. The mortality experience of the cohort was ascertained through computerized record linkage and compared to that of the male Ontario population specific to cause, age, and calendar period from 1950 through 1989. Average duration of follow-up was 21 years, and there were 777 deaths among the 5,414 males included in the analysis, giving an all-cause standardized mortality ratio of 95 (95% confidence interval: 88-102). Three specific causes of death exhibit statistically significant excesses (brain tumors, "other" malignant neoplasms, and aortic aneurysms). There are also slight increases in risk for some other sites of cancer, and for various diseases of the respiratory, circulatory, and digestive systems. This study is consistent with others in demonstrating that fire fighters experience increased risk of death from cancer of the brain, and in suggesting increased risk for various other causes of death.