The international comparability of cancer mortality data. Results of an international death certificate study

In preparation for the 10th revision of the International Classification of Diseases (ICD-10), a two-part study was undertaken to assess the international comparability of the coding, by the 9th revision (ICD-9), of death certificates mentioning cancer, to see whether there had been improvement since the 8th revision (ICD-8). Part I repeated a 1978 study in which nine countries coded the same 1,234 United States death certificates mentioning cancer by ICD-9. The proportion of disagreements in coding the underlying cause of death fell about 35% between 1978 and the present study. This reduction was probably due to the new more detailed rules for coding cancer death certificates given in ICD-9. To combat the criticism of the possible bias associated with using United States death certificates only, in Part II of the study, each of seven countries submitted about 100 certificates translated into English which had posed problems in coding cancer. Discrepancies in assigning the underlying cause of death were found for 54% of these problem certificates. The major types of problems identified were coding when multiple cancer sites were mentioned on the death certificate, whether to select heart disease or cancer as the underlying cause of death, and the interpretation of the coding rules. Better rules for ICD-10 must be provided for both physicians and coders if international comparability of cancer mortality data is to be achieved.     

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.     

Serum concentrations of carotenoids and vitamins A, E, and C in control subjects from five European countries

High intakes of fruits and vegetables, or high circulating levels of their biomarkers (carotenoids, vitamins C and E), have been associated with a relatively low incidence of cardiovascular disease, cataract and cancer. Exposure to a high fruit and vegetable diet increases antioxidant concentrations in blood and body tissues, and potentially protects against oxidative damage to cells and tissues. This paper describes blood concentrations of carotenoids, tocopherols, ascorbic acid and retinol in well-defined groups of healthy, non-smokers, aged 25-45 years, 175 men and 174 women from five European countries (France, UK (Northern Ireland), Republic of Ireland, The Netherlands and Spain). Analysis was centralised and performed within 18 months. Within-gender, vitamin C showed no significant differences between centres. Females in France, Republic of Ireland and Spain had significantly higher plasma vitamin C concentrations than their male counterparts. Serum retinol and alpha-tocopherol levels were similar between centres, but gamma-tocopherol showed a great variability being the lowest in Spain and France, and the highest in The Netherlands. The provitamin A: non-provitamin A carotenoid ratio was similar among countries, whereas the xanthophylls (lutein, zeaxanthin, beta-cryptoxanthin) to carotenes (alpha-carotene, beta-carotene, lycopene) ratio was double in southern (Spain) compared to the northern areas (Northern Ireland and Republic of Ireland). Serum concentrations of lutein and zeaxanthin were highest in France and Spain; beta-cryptoxanthin was highest in Spain and The Netherlands; trans-lycopene tended to be highest in Irish males and lowest in Spanish males; alpha-carotene and beta-carotene were higher in the French volunteers. Due to the study design, the concentrations of carotenoids and vitamins A, C and E represent physiological ranges achievable by dietary means and may be considered as 'reference values' in serum of healthy, non-smoking middle-aged subjects from five European countries. The results suggest that lutein (and zeaxanthin), beta-cryptoxanthin, total xanthophylls and gamma-tocopherol (and alpha- : gamma-tocopherol) may be important markers related to the healthy or protective effects of the Mediterranean-like diet.     

Comparison of LDL fatty acid and carotenoid concentrations and oxidative resistance of LDL in volunteers from countries with different rates of cardiovascular disease

Within Europe there are differences in cardiovascular disease (CVD) risk between countries and this might be related to dietary habits. Oxidative modification of LDL is suggested to increase the risk of CVD and both the fatty acid and antioxidant content of LDL can affect its oxidation. In the present study, concentration of LDL fatty acid and antioxidant micronutrients (tocopherols and carotenoids) and ex vivo oxidative resistance of LDL (lag phase) was compared in volunteers from five countries with different fruit and vegetable intakes and reported rates of CVD. Eighty volunteers (forty males, forty females per centre), age range 25-45 years, were recruited from France, Northern Ireland, UK, Republic of Ireland, The Netherlands, and Spain, and their LDL composition and lag phase were measured. There were some differences in LDL carotenoid and alpha-tocopherol concentrations between countries. alpha-Tocopherol was low and beta- + gamma-tocopherol were high (P<0.001) in the Dutch subjects. Beta-Carotene concentrations were significantly different between the French and Spanish volunteers, with French showing the highest and Spanish the lowest concentration. LDL lycopene was not different between centres in contrast to lutein, which was highest in French (twofold that in the Dutch and Spanish and threefold that in Northern Ireland and the Republic of Ireland, P<0.001). However absolute LDL saturated, monounsaturated, polyunsaturated and total unsaturated fatty acid concentrations were different between countries (P<0.001, total unsaturated highest in Northern Ireland) there was little difference in unsaturated:saturated fatty acid concentration ratios and no difference in polyunsaturated:saturated fatty acid concentration ratios. LDL from the Republic of Ireland (a region with a high rate of CVD) had greater resistance to Cu-stimulated oxidation than samples obtained from volunteers in other countries. In conclusion, LDL composition did not predict resistance to Cu-stimulated oxidation, nor is there evidence that LDL from volunteers in countries with lower rates of CVD have greater resistance to oxidation.     

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.     

Patterns of alcohol consumption in middle-aged men from France and Northern Ireland. The PRIME study

OBJECTIVE: To assess the patterns of alcohol consumption in France and Northern Ireland. DESIGN: Four cross-sectional studies. SETTING: Sample of 50-59 y old men living in France and Northern Ireland, consuming at least one unit of alcoholic beverage per week. SUBJECTS: 5363 subjects from France and 1367 from Northern Ireland. INTERVENTIONS: None. RESULTS: Consumption of wine was higher in France whereas consumption of beer and spirits was higher in Northern Ireland. Alcohol drinking was rather homogeneous throughout the week in France, whereas Fridays and Saturdays accounted for 60% of total alcohol consumption in Northern Ireland. In both countries, current smokers had a higher consumption of all types of alcoholic beverages than non-smokers. Similarly, obese and hypertensive subjects had a higher total alcohol consumption than non-obese or normotensive subjects, but the type of alcoholic beverages differed between countries. In Northern Ireland, subjects which reported some physical activity consumed significantly less alcoholic beverages than sedentary subjects, whereas no differences were found in France. Conversely, subjects with dyslipidemia consumed more alcoholic beverages than normolipidemic subjects in France, whereas no differences were found in Northern Ireland. In France, total alcohol, wine and beer consumption was negatively related to socioeconomic status and educational level. In Northern Ireland, total alcohol, beer and spirits consumption was negatively related whereas wine consumption was positively related to socioeconomic status and educational level. CONCLUSIONS: Alcohol drinking patterns differ between France and Northern Ireland, and also according to cardiovascular risk factors, socioeconomic and educational levels. SPONSORSHIP: Merck, Sharp & Dohme-Chibret (France), the NICHSA and the Department of Health and Social Service (Northern Ireland).     

The burden of diabetes-related mortality in France in 2002: an analysis using both underlying and multiple causes of death

Aim To describe the burden of diabetes-related mortality in France. Methods Underlying and multiple causes (all causes listed) of death were extracted from the 2002 French national mortality registry. Death rates were standardized on the age structure of the European population. Results Diabetes was reported as the underlying cause of death in 11,177 certificates (2.1%), and as multiple causes in 29,357 certificates (5.3%), giving a ratio (multiple/underlying causes) of 2.6. When diabetes was a multiple cause, the mean age at death was 75 years in men, 81 years in women. The age-standardized mortality rates were 41.0/100,000 in men, 24.6/100,000 in women. The excess mortality observed in men (men/women ratio = 1.7) decreased with age. Geographic differences were observed: higher rates in the North-East, lower rates in the West of the country. In certificates mentioning diabetes, the most frequent cause of death was diseases of the circulatory system (76%). Coronary heart diseases, foot ulcers and renal diseases were more likely to be mentioned in certificates referring to diabetes than in those that did not. Discussion The use of multiple rather than underlying causes of death more than doubled diabetes-related mortality rates. While probably still under-estimated, the burden of diabetes-related mortality corresponds to a high proportion of the total mortality, especially in men. Geographic differences partially reflect disparities in diabetes prevalence. Causes more frequently associated with diabetes include coronary heart disease and complications related to neuropathy and nephropathy.     

The reliability of cause-of-death coding in The Netherlands

Cause-of-death statistics are a major source of information for epidemiological research or policy decisions. Information on the reliability of these statistics is important for interpreting trends in time or differences between populations. Variations in coding the underlying cause of death could hinder the attribution of observed differences to determinants of health. Therefore we studied the reliability of cause-of-death statistics in the Netherlands. We performed a double coding study. Death certificates from the month of May 2005 were coded again in 2007. Each death certificate was coded manually by four coders. Reliability was measured by calculating agreement between coders (intercoder agreement) and by calculating the consistency of each individual coder in time (intracoder agreement). Our analysis covered an amount of 10,833 death certificates. The intercoder agreement of four coders on the underlying cause of death was 78%. In 2.2% of the cases coders agreed on a change of the code assigned in 2005. The (mean) intracoder agreement of four coders was 89%. Agreement was associated with the specificity of the ICD-10 code (chapter, three digits, four digits), the age of the deceased, the number of coders and the number of diseases reported on the death certificate. The reliability of cause-of-death statistics turned out to be high (>90%) for major causes of death such as cancers and acute myocardial infarction. For chronic diseases, such as diabetes and renal insufficiency, reliability was low (<70%). The reliability of cause-of-death statistics varies by ICD-10 code/chapter. A statistical office should provide coders with (additional) rules for coding diseases with a low reliability and evaluate these rules regularly. Users of cause-of-death statistics should exercise caution when interpreting causes of death with a low reliability. Studies of reliability should take into account the number of coders involved and the number of codes on a death certificate.     

Multiple causes of death in diabetics in the municipality of Recife, 1987]

In 1987, diabetes mellitus was mentioned in 492 death certificates of the population of the city of Recife, Brazil, 202 of them for males and 290 for females. Diabetes mellitus was the underlying cause of death according to 80 certificates for men and 290 for women, as a result of which premature death occurred in 16.2% of men and 11.1% of women. Multiple cause of death analysis showed that cardiovascular diseases were the most frequent underlying cause of death in individuals over 50 years of age and acute complications of diabetes mellitus in individuals under 50. Cerebrovascular diseases were the most frequent in the cardiovascular group, particularly in females. Arterial hypertension was the most frequent associated cause of death appearing in death certificates mentioning diabetes mellitus (not as the underlying cause of death), also more often in females. The acute complications of diabetes mellitus (keto-acidosis and coma) and peripheral circulatory disorders peculiar to this disease caused 23% and 30% of the deaths, respectively, in cases where diabetes mellitus was the underlying cause. Infectious and parasitic diseases were the most frequent associated causes of death according to those certificates which gave diabetes mellitus as the underlying cause.     

Making COD statistics useful for public health at local level in the city of Cape Town: utilidad para la salud pública a nivel local en Ciudad del Cabo

OBJECTIVE: To review the quality of the coding of the cause of death (COD) statistics and assess the mortality information needs of the City of Cape Town. METHODS: Using an action research approach, a study was set up to investigate the quality of COD information, the accuracy of COD coding and consistency of coding practices in the larger health subdistricts. Mortality information needs and the best way of presenting the statistics to assist health managers were explored. FINDINGS: Useful information was contained in 75% of death certificates, but nearly 60% had only a single cause certified; 55% of forms were coded accurately. Disagreement was mainly because routine coders coded the immediate instead of the underlying COD. An abridged classification of COD, based on causes of public health importance, prevalent causes and selected combinations of diseases was implemented with training on underlying cause. Analysis of the 2001 data identified the leading causes of death and premature mortality and illustrated striking differences in the disease burden and profile between health subdistricts. CONCLUSION: Action research is particularly useful for improving information systems and revealed the need to standardize the coding practice to identify underlying cause. The specificity of the full ICD classification is beyond the level of detail on the death certificates currently available. An abridged classification for coding provides a practical tool appropriate for local level public health surveillance. Attention to the presentation of COD statistics is important to enable the data to inform decision-makers.     

Reporting of diabetes on death certificates of 1872 people with type 2 diabetes in Tayside, Scotland

BACKGROUND: It has been suggested that diabetes is under-recorded on death certificates. METHODS: We examined the death certificates of 1,872 people with type 2 diabetes in Tayside, Scotland, to determine how frequently diabetes was recorded. RESULTS: Diabetes was mentioned on the certificates of 42.8% and was the underlying cause of death for 6.4%. There was mention of diabetes for 51.3% of the 811 people for whom cardiovascular disease was the underlying cause of death. Being male was associated with less frequent mention of diabetes, with more frequent mention associated with increasing duration of diabetes, increasing age and underlying cardiovascular cause of death. CONCLUSIONS: This study highlights the limitations of using routine mortality data for monitoring the burden of diabetes in populations.     

Multiple-cause coding of death from myocardial infarction: population-based study of trends in death certificate data

BACKGROUND: Data on long-term trends in mortality are generally unavailable for multiple-cause coding of deaths. We wanted to know whether multiple-cause coding of deaths for myocardial infarction contributes much to the interpretation of death certificate data on mortality rates for this condition. METHODS: We analysed all causes of death on death certificates in the former Oxford health service region from 1979 to 1998. RESULTS: Of 69,333 death certificates that included myocardial infarction as a cause of death, it was the underlying cause of death in 93.6 per cent. The ratio of 'mentions' to 'underlying cause' was broadly similar over the study period, during which time there were substantial falls in mortality rates. There were significant changes to the ratios, associated with timing of changes to coding rules; but their effects were small. The ratio of mentions to underlying cause was similar in men and women and in different age groups. CONCLUSION: The underlying cause of death was a robust and almost complete measure of certified deaths for myocardial infarction.     

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.     

Underlying cause of death from external causes: validation of official data in Recife, Pernambuco, Brazil]

OBJECTIVE: To validate the underlying cause of death recorded on the death certificates for individuals under 20 years of age who died from external causes in 1995 in Recife, Pernambuco, Brazil. METHODS: We divided the study into two stages, coding and validation. In both stages we compared the official data concerning causes of death to the data we obtained during our study. We grouped the death certificates into 5 broad categories according to the cause of death; we later subdivided them into 14 categories. We also individually compared the death certificates applying the four-digit system of the International Classification of Diseases, Ninth Revision (ICD-9). We assessed the agreement between the official data and our data in terms of sensitivity and the kappa coefficient. We took as the standard the categorization of the cause of death that we had made during our investigation. RESULTS: In the coding stage, considering all the external causes of death, the overall agreement between the official data and our study data was 94% for the 5 categories, 92% for the 14 categories, and 81% for the four-digit ICD-9 system. In the validation stage the overall agreement was 94% for the 5 categories, 91% for the 14 categories, and 73% for the four-digit ICD-9 system. CONCLUSIONS: Our results suggest that for the death certificates to be reliable, the Institute of Legal Medicine must fill them out following recommended standards. In addition, hospitals and police departments must use greater care in completing the transfer slips that accompany the bodies that are sent to the Institute. More accurate data need to be generated and disseminated for a society to better understand its patterns of violence.     

Pandemic strain of foot-and-mouth disease virus serotype O

A particular genetic lineage of foot-and-mouth disease virus (FMDV) serotype O, which we have named the PanAsia strain, was responsible for an explosive pandemic in Asia and extended to parts of Africa and Europe from 1998 to 2001. In 2000 and 2001, this virus strain caused outbreaks in the Republic of Korea, Japan, Russia, Mongolia, South Africa, the United Kingdom, Republic of Ireland, France, and the Netherlands, countries which last experienced FMD outbreaks decades before (ranging from 1934 for Korea to 1984 for the Netherlands). Although the virus has been controlled in all of these normally FMD-free or sporadically infected countries, it appears to be established throughout much of southern Asia, with geographically separated lineages evolving independently. A pandemic such as this is a rare phenomenon but demonstrates the ability of newly emerging FMDV strains to spread rapidly throughout a wide region and invade countries previously free from the disease.     

Variation in mortality by country of birth in Northern Ireland: a record linkage study

The study of health differences between those residing in the same country but originating in different countries is a potential source of insight into the causes of ill-health. Within Northern Ireland, those born in England, Wales, the Republic of Ireland and outside of the British Isles have a lower mortality risk than the Northern Ireland born; however, these differentials are largely explained by the demographic and socio-economic characteristics of these migrants. Conversely, the Scottish born residing in Northern Ireland have higher mortality than the Northern Ireland born, especially from ischemic heart disease, suggesting that the Scottish immigrants maintain the health disadvantage of their country of birth.     

Population-based breast cancer screening is not worthwhile. Screening has little effect on mortality

Comparison of breast cancer mortality between pairs of similar countries (Sweden and Norway, Northern Ireland and the Irish Republic, the Netherlands and Belgium or Flanders), each of which had implemented its population-wide breast cancer screening programme at a different point in time, demonstrated little effect of screening on mortality. In the Netherlands, a well-organised population-wide screening programme was started in the early nineties, ten years before such a programme was introduced in Flanders. We used the 1989-1992 period as a baseline and compared breast cancer mortality in the Netherlands with that in Flanders during the 2005-2008 period. The added value of organised screening was low: 11% in the target age group of 55-79 years, or 180 prevented breast-cancer deaths annually. A total of 5000 screening mammograms were needed to prevent one death from breast cancer. Breast cancer screening is not a public health priority. Impartial and transparent information on the disadvantages and benefits of breast cancer screening is urgently needed.     

Comparing hospital discharge records with death certificates: Can the differences be explained?

STUDY OBJECTIVE: The quality of mortality statistics is important for epidemiological research. Considerable discrepancies have been reported between death certificates and corresponding hospital discharge records. This study examines whether differences between the death certificate's underlying cause of death and the main condition from the final hospital discharge record can be explained by differences in ICD selection procedures. The authors also discuss the implications of unexplained differences for mortality data quality. DESIGN: Using ACME, a standard software for the selection of underlying cause of death, the compatibility between the underlying cause of death and the final main condition was examined. The study also investigates whether data available in the hospital discharge record, but not reported on the death certificate, influence the selection of the underlying cause of death. SETTING: Swedish death certificates for 1995 were linked to the national hospital discharge register. The resulting database comprised 69 818 people who had been hospitalised during their final year of life. MAIN RESULTS: The underlying cause of death and the main condition differed at Basic Tabulation List level in 54% of the deaths. One third of the differences could not be explained by ICD selection procedures. Adding hospital discharge data changed the underlying cause in 11% of deaths. For some causes of death, including medical misadventures and accidental falls, the effect was substantial. CONCLUSION: Most differences between underlying cause of death and final main condition can be explained by differences in ICD selection procedures. Further research is needed to investigate whether unexplained differences indicate lower data quality.     

根本死因自动编码工具的应用研究

为提高常规死因监测中根本死因编码的准确性，按照WHO的ICD-10根本死因编码规则及国际上同类软件开发设计原理，并参照美国编码策略表，通过计算机语言实现根本死因编码的自动化，研制基于全国死因登记报告信息系统的根本死因自动编码工具，其根本死因编码正确率达到85 %，实现了对死亡个案数据的自动编码，且编码正确率达到国际同类软件水平。     

Prevalence of neural tube defects in 20 regions of Europe and the impact of prenatal diagnosis, 1980-1986. EUROCAT Working Group.

STUDY OBJECTIVE--The aims were (1) to determine whether in Europe, 1980-86, geographical differences in total prevalence of neural tube defects persist; (2) to examine the stability of total prevalence rates over time; (3) to evaluate the impact of prenatal diagnosis in terms of frequency and timing of termination of pregnancy. DESIGN--Prevalence rates of neural tube defects were determined from case registration data in 20 EUROCAT regional registers of congenital anomalies, 1980-86. The chi 2 test for homogeneity in proportions was used to test whether differences in total prevalence rates were significant between regions or over time. SETTING--Geographically defined populations were used in the Republic of Ireland, United Kingdom, Belgium, The Netherlands, Luxemburg, Denmark, France, Italy, Yugoslavia, and Malta. PATIENTS--The patients were 3113 cases of anencephaly, spina bifida, encephalocele, and iniencephaly. Total cases (livebirths, stillbirths and induced abortions following prenatal diagnosis) were registered in 14 regions. Induced abortions were excluded from registration in six regions. MEASUREMENTS AND MAIN RESULTS--Total prevalence rates (including livebirths, stillbirths and induced abortions) were 24 to 38 per 10,000 in six areas of Ireland and United Kingdom. Average total prevalence rate in eight continental European areas was 11.5 per 10,000. There was a secular decline in total prevalence in Dublin (Republic of Ireland) and Northern Ireland (United Kingdom) and a fluctuation in Glasgow, Liverpool, and South Glamorgan (United Kingdom). Total prevalence in continental Europe was stable over time. There was no significant geographical or secular variation in the spina bifida to anencephaly ratio (1.3). The ratio of encephalocele to other neural tube defects was lower in the British Isles (0.09) than in continental Europe (0.18). The impact of prenatal diagnosis and termination of pregnancy is increasing over time. Terminations were performed 1984-86 in at least 80% of total cases of anencephaly in 6/11 centres registering induced abortions, and in at least 40% of total cases of spina bifida in four centres. Serum alpha fetoprotein screening in British centres was associated with earlier prenatal diagnosis of spina bifida than ultrasound screening in other centres. CONCLUSIONS--Geographical and secular variation in total prevalence of neural tube defects persists in Europe 1980-86, independent of the practice of prenatal diagnosis. There is considerable regional variation in the impact of prenatal diagnosis in terms of frequency and timing of diagnosis and pregnancy termination linked to different policies and practices of prenatal screening.