The Swedish cause of death register

Sweden has a long tradition of recording cause of death data. The Swedish cause of death register is a high quality virtually complete register of all deaths in Sweden since 1952. Although originally created for official statistics, it is a highly important data source for medical research since it can be linked to many other national registers, which contain data on social and health factors in the Swedish population. For the appropriate use of this register, it is fundamental to understand its origins and composition. In this paper we describe the origins and composition of the Swedish cause of death register, set out the key strengths and weaknesses of the register, and present the main causes of death across age groups and over time in Sweden. This paper provides a guide and reference to individuals and organisations interested in data from the Swedish cause of death register.     

New dimensions in cause of death statistics.

This article discusses the limitations of traditional national cause of death statistics. These limitations derive from an attempt to conceptualize a multidimensional phenomenon and reduce down to a unidimensional framework. The article outlines the characteristics of a new multidimensional approach which involves the codification and tabulation of all causes (multiple causes) listed on death certificates. Preliminary data are presented which illustrate that multiple cause of death data do indeed represent a major new dimension to cause of death statistics. These data indicate that most major causes of death are contributory factors in many deaths in which they are not the underlying cause of death. For example, in 1976, diabetes mellitus was the underlying cause of approximately 35,000 deaths but was a contributing factor in another 100,000 deaths. This paper also demonstrates the contribution of multiple cause of death data to identifying patterns of association among diseases and the kinds of injuries resulting from various external causes. Finally, data are presented which depict the use of multiple cause data in evaluating the efficacy of the coding rules used to classify the underlying cause of death.     

The coding of underlying cause of death from fetal death certificates: issues and policy considerations.

Recently, plans to implement nationwide coding of underlying cause of fetal death have been promulgated. To examine the validity and potential utility of nationwide coding, this paper presents data from a five-state (Wisconsin, Arkansas, Maine, North Carolina, California) analysis of underlying causes of fetal death from vital records for 1985 through 1987. Nosological coding rules varied somewhat from state to state. Underlying causes were grouped into categories; distributions were similar for each state. Many deaths (20.3% to 32.9%) were coded as unspecified conditions. Congenital anomalies accounted for only 6.9% to 10.3% of fetal deaths, including implausible and nonspecific causes. In total, 29.5% to 42.8% of the reports were not valid or useful. To obtain better data, researchers must focus on improving fetal death reporting, which will entail the promotion of comprehensive autopsy, placental and laboratory evaluation, systematic vital records query procedures, and implementation of multiple-cause-of-fetal-death coding.     

Mortality and cause of death in Down''s syndrome.

Mortality in sufferers from Down's syndrome over the age of 1 year in the 1970s was analysed using the Wessex Mental Handicap Register linked to the NHS Central Register. Of the 1045 subjects, 37 died during the period of the study; the standardised mortality ratio based on England and Wales mortality was 5.39. Mortality ratios were high between the ages of 1 and 14 compared with older ages. Bronchopneumonia and congenital heart disease were the main causes of death. Problems with certification and selection of underlying cause of death showed the potential value of multiple-cause coding.     

The accuracy of liver cancer as the underlying cause of death on death certificates

Studies of liver cancer mortality are subject to confusion attributable to the changes in categories by which liver cancer is identified in successive revisions of the International Classification of Diseases. To determine the effects of these changes, diagnoses of 2,388 cases of primary liver cancer in the years 1973-80 were compared to the underlying causes of death recorded on the death certificates, using data from the National Cancer Institute's Surveillance, Epidemiology, and End Results Program. Results showed that only 53 percent of the deaths were attributed on death certificates to primary liver cancer. In a reverse comparison of 2,977 death certificates from the years 1973-85 with an underlying cause of death of primary liver cancer, 83 percent had been diagnosed as liver cancer. However, among the certificates that specified cancer of the liver, not specified as primary or secondary, as the cause of death, only 40 percent had been diagnosed originally as liver cancer. The mortality of liver cancer can be either underestimated or overestimated depending on which disease classification categories are used.     

Certification of cause of death in French diabetic patients.

STUDY OBJECTIVE--The aim was to assess the level of mortality related to diabetes in France. In other countries, an underrecording of diabetes on the death certificates of diabetic patients has been reported. DESIGN AND SETTING--Estimated death rate of diabetic patients was calculated using (a) the actual number of death certificates where diabetes was registered either as an underlying or as a contributory cause of death, and (b) estimates of the prevalence of diabetes in the population, by sex and age group, from which expected numbers of diabetic deaths were determined. Standardised mortality ratios were calculated using 1988 French mortality statistics as reference. MAIN RESULTS--The estimated standardised mortality ratio for diabetic subjects, with diabetes registered as the underlying cause, was 0.36. This standardised mortality ratio increased to 0.92 if both the underlying and contributory causes were considered. The estimated death rate, by sex and age group, implies that diabetes has a protective effect between the ages of 45 and 64 years, particularly in men. CONCLUSIONS--Evidence suggests that diabetes is completely omitted on the death certificates of many diabetic subjects, especially for those between the ages of 45 and 64 years. Using mortality statistics underestimates the prevalence of diabetes and its effects on public health. The difference in diabetes mortality between countries will not be reliable until there is a better registration of the causes of death in diabetic patients, and contributory as well as the underlying cause are coded and published.     

Nosological coding of cause of death

Death certificates representing 766 decedents who had participated in the Hypertension Detection and Follow-up Program (1973-1979) at one of 14 US centers were given to three nosologists for purposes of coding underlying cause of death. Analyses examined interobserver variability among the three nosologists as well as intraobserver variability for each of the three nosologists. All three nosologists agreed on a three-digit International Classification of Diseases, Adapted (ICDA) code in 90.2% of the cases and at least two out of three agreed in 99.7% of the death certificates examined. Agreement rates improved when disease codes were collapsed into broader categories utilized in the Hypertension Detection and Follow-up Program. When particular disease classifications (e.g., cerebrovascular, ischemic heart disease, myocardial infarction, and neoplasms) were examined, three out of three agreement rates were highest for neoplasms (97.8%) and lowest for myocardial infarction (86.5%). Similarly, two out of three agreement was highest for neoplasms (98.5%) and lowest for myocardial infarction (88.0%). Intranosologist agreement rates were based on a recoded 20% sample of death certificates. Agreement rates for three-digit ICDA codes ranged from 94.8% to 96.1% for the three nosologists. The agreement rates for the general disease categories ranged from 96.7% to 97.4%.     

2011年长春市居民死亡原因调查分析

目的了解长春市全死因监测点死因分布特点,计算长春市5城区居民期望寿命以及重要死因对期望寿命的影响,为慢性病的预防、控制提供依据。方法利用死亡率、构成比及期望寿命对2011年五城区居民死亡资料进行统计分析。结果 2011年5城区居民总死亡率5.23‰,男性高于女性。前5位死因依次是心脏病、恶性肿瘤、脑血管病、呼吸系统疾病及其他疾病,占总死因的83.43%。本市5城区居民期望寿命78.56岁,女性期望寿命高于男性。如果去除主要死因,长春市期望寿命将有提高。结论慢性病在总死亡中所占比例最高,是目前危害本市居民健康的主要疾病和死因,预防和控制慢性病是当务之急。     

Diabetes mellitus as cause of death

Certification and coding of diabetes mellitus as a cause of death were investigated by sending a random sample of 300 physicians a set of 6 case histories. Of these, 228 (76%) participated in the study by completing a death certificate for each of these cases. The certificates were subsequently coded by the Central Bureau of Statistics. The main finding was that doctors varied enormously in the way in which diabetes mellitus was mentioned on the death certificate: not at all, as a contributory cause of death, or as an underlying cause of death. Coding removes some of the inconsistencies, but induces additional variation: a higher age of the deceased is associated with a lower probability of having diabetes mellitus coded as the underlying cause of death, and a higher probability of not receiving a code of diabetes mellitus at all. It is concluded that the cause-of-death registration does not provide an accurate picture of the contribution of diabetes mellitus to the cause-of-death pattern of the Netherlands. This is due, amongst other things, to the conceptualization of causes of death on which the registration is based. On the other hand, changes in certification and coding practice within the current system may already lead to some improvement.