Using multiple cause of death coding in occupational mortality studies

Conventional occupational mortality analysis, using underlying cause of death coding, underestimates the contribution of those chronic diseases which are mentioned on the death certificate but which usually do not appear as underlying cause of death. Proportionate occupational mortality analysis, using all the mentioned causes on the Washington State male death records 1968-1984, identified an excess of rheumatoid arthritis in farmers, and asbestosis in plumbers, pipefitters, and steamfitters.     

The impact on relative risk estimates of inconsistencies between ICD-9 and ICD-10

Background

The 10th revision of the International Classification of Diseases (ICD) represents a major change in the ICD system. This paper investigates the impact on relative risk estimates of inconsistencies in outcome classification between ICD‐9 and ICD‐10, including scenarios in which occupational exposure levels are correlated with year of death (and therefore with the ICD revision in effect at death). The setting of interest is a cohort mortality study in which follow up spans the periods during which ICD‐9 and ICD‐10 were in effect. The relative risk estimate obtained when death certificates are coded to the ICD revision in effect at time of death is compared to the relative risk estimate that would be obtained if all death certificates were coded to a consistent ICD revision (that is, ICD‐10). The ratio of these relative risks is referred to as the coefficient of bias.

Methods

Simple equations relate the coefficient of bias to the sensitivity and specificity of the classification of decedents into categories of cause of death via ICD‐9 (treating classifications based upon ICD‐10 as the standard). Bridge coded mortality data for 2 296 922 decedents (that is, death certificates coded to ICD‐9 and ICD‐10) are used to derive estimates of sensitivity and specificity by category of cause of death. Numerical examples illustrate the application of these equations.

Results

Estimates of the sensitivity of classification of decedents into categories of death defined by ICD‐9 ranged from 0.26–1.00. Specificity was above 0.98 for all categories of cause of death. Numerical examples illustrate that inconsistencies in outcome classification between ICD‐9 and ICD‐10 may have substantial impact on relative risk estimates if there is a strong relation between exposure status and the proportion of deaths coded to a given ICD revision.

Conclusions

For analyses of mortality outcomes that exhibit poor comparability between ICD‐9 and ‐10, it may be prudent to recode cause of death information to a standard ICD revision in order to avoid bias that can occur when exposures are correlated with the proportion of deaths coded to a given ICD revision.     

Underlying and multiple cause mortality in a cohort of workers exposed to aromatic amines

Background The National Institute for Occupational Safety and Health (NIOSH) has previously conducted studies of bladder cancer incidence and mortality at a synthetic dye plant that manufactured beta-naphthylamine from 1940 through 1979. This report extends the period of mortality follow-up 13 years and analyzes both underlying and nonunderlying causes of death. Methods The vital status of each cohort member, as of December 31, 1992, was determined by using the National Death Index and information from the Internal Revenue Service and the U.S. Postal Service. The NIOSH life table analysis system (LTAS) was used to generate person-years-at-risk and the expected numbers of death for 92 categories of death, using several referent rates (U.S. underlying, Georgia underlying, U.S. multiple cause). Results There were three bladder cancer deaths listed as underlying cause, yielding a standardized mortality ratio (SMR) based on U.S. rates of 2.4 (95% confidence interval (CI) = 0.5, 7.0) and a total of eight bladder cancers listed anywhere on the death certificates (SMR based on multiple cause referent rates = 5.6; 95% CI = 2.4, 11.1). Mortality from esophageal cancer, which had been significantly elevated in the previous study, was no longer significantly elevated (SMR = 2.0; 95% CI = 0.8,4.1). Mortality from all causes was significantly higher than expected (SMR = 1.5; 95% CI = 1.3, 1.6). Conclusions The elevated bladder cancer risk in this cohort was detected by the multiple cause, but not the underlying cause, analysis. Elevated mortality from other causes of death, especially among short-term workers, may be related to regional and lifestyle factors. Am. J. Ind. Med. 34:506–511, 1998. © 1998 Wiley-Liss, Inc.     

A medical cause of death validation study of adult Aboriginal deaths in the Northern Territory of Australia in 1992

Judged on the criterion of equity, premature adult Aboriginal mortality is the most serious public health problem faced in Australia today. There have been a number of published epidemiological studies that have analysed Aboriginal cause of death data, but this is the first study to formally validate such data. The study sample included all adult Aboriginal people who lived and died in the Northern Territory in 1992, excluding residents of the Alice Springs region. The appropriateness of underlying cause of death codes was assessed by a single reviewer in light of death certificates, medical records, postmortem records and interviews with key health professional informants. Data were collected on 220 deaths. 8% (17 out of 220) of deaths were classified erroneously at the ICD-9 chapter level. Errors in death certification accounted for 64% (11 out of 17) of the chapter errors and diagnostic and coding errors for 18% (3 out of 17) each. The overall impact on mortality statistics was less severe because some cross-chapter classification errors cancelled each other out. Misclassification errors aggregated mainly in chapter VII (circulatory diseases) of the ICD-9 classification which was overcounted by 3.2%, and chapter VIII (respiratory diseases) which was overcounted by 1.3%. Before correction for misclassification error, circulatory diseases were judged to cause the highest proportion of deaths, whereas after correction, respiratory diseases accounted for the highest proportion. Despite this, the overall quality of the medical cause of death statistics was of a sufficiently good standard from a public health perspective to broadly inform health policy. Future attempts to improve the validity of medical cause of death statistics for Australian Aboriginal people should focus on the education of medical practitioners about the purpose and process of death certification.     

Cancer and occupation in Massachusetts: a death certificate study

This study examines cancer mortality patterns by occupation for white males in Massachusetts using 1971-1973 death records. Its purpose is to identify occupation-cancer associations that, when interpreted in conjunction with results from other studies and hypotheses about potential occupational carcinogens, can serve as leads for more definitive etiological investigations. Sixty-two malignancy categories (including grouped categories) were investigated for each of 397 occupational categories (including grouped categories) using an age-standardized mortality odds ratio approach. An important finding was the association between lung cancer and a large number of occupations for which there is support from other epidemiologic studies and/or for which there are reasonable hypotheses as to possible carcinogenic exposures. These occupations include truck drivers, painters, machinists, automobile mechanics, plumbers, cooks, fishermen, heated metal workers, sheet metal workers, and brickmasons/stonemasons/tile setters.     

Use of death certificates in epidemiological studies, including occupational hazards: variations in discordance of different asbestos-associated diseases on best evidence ascertainment.

There is extensive information on discordance in general between accuracy of medical diagnoses on death certificate categorization of cause of death and available clinical and histopathological data. This is as true for occupational disease as for other conditions. But occupational illnesses bear a special problem. Discordance is not equal across the board--it may vary with each occupationally related disease, and no single formula can be applied. It may be high for angiosarcoma and low for acute hydrogen sulfide poisoning, low for bladder cancer, high for unsuspected methyl mercury poisoning. We have found that for one agent--asbestos--there were different rates of discordance for different asbestos-related diseases (e.g., lung cancer, mesothelioma, asbestosis, kidney cancer) among 4,951 deaths studied prospectively from 1967 to 1986. Caution is therefore required before accepting generalizations concerning (unstudied) discordance in occupational mortality studies, and in their use in risk assessment models.     

江苏省第三次死因回顾调查恶性肿瘤死亡水平分析

目的:了解江苏省21世纪初居民主要恶性肿瘤的死亡特征.方法:利用2003年～2005年江苏省第三次死因回顾调查数据,分析人群中恶性肿瘤的死亡率、标化死亡率、死因构成、死因顺位等指标及死亡率之性别、年龄、城乡、地区差别.结果:江苏省2003年～2005年居民恶性肿瘤死亡率为208.99/10万,标化死亡率为116.45/...     

Death certificate-based occupational mortality surveillance in the United States

Surveillance of cause-specific mortality patterns by occupation and industry through the use of death certificate records is a simple and relatively inexpensive approach to the generation of leads as to potential occupational disease problems. Researchers from the National Institute for Occupational Safety and Health (NIOSH) have been working with the National Center for Health Statistics, other federal agencies, and state health departments on a number of programs to foster the development of standardized, routine coding of occupation and industry entries on death certificates by state health departments. Thirty-one states and the District of Columbia are now doing such coding. These data are being analyzed currently by investigators at NIOSH and at individual state health departments for the purpose of hypothesis generation on occupation-disease relationships. The proportionate mortality ratio method is the predominant method being used, as appropriate denominator data are not generally available. This type of surveillance is particularly useful for the study of occupation and industry groups for which it is difficult to assemble cohorts, such as groups that are predominantly non-union and in small workplaces. Limitations of this surveillance include its inappropriateness for monitoring those occupational diseases which are not often fatal, and the limited scope and accuracy of death certificate information.     

A comparison of analyses of occupational bladder cancer: Death certificate vs. population-based case-control interview data

The authors examined the utility of death certificate data for occupational health surveillance by comparing the ability of the data to identify high-risk occupations for bladder cancer with that of a population-based case-control study. Death certificate data for white males from 23 states for 1979–1987 were analyzed using proportionate mortality ratios. The case-control study used cancer registry cases for 1977–1978. Results were compared for 21 a priori suspect occupations. A broad definition of agreement resulted in agreement for 62% of the occupations; the death certificate study identified eight of 15 occupations identified by the case-control study and neither study identified five of the categories. While death certificate data have many limitations, our results indicate that death certificate data can provide clues to some potential occupational health problems. With the advantages of inexpensive data, large sample size, and industrial coverage, more refined analyses of the data should prove useful for occupational mortality surveillance and hypothesis generation. © 1994 Wiley-Liss, Inc.     

四川省婴儿可避免死亡分析

【目的】 明确四川省婴儿可避免死亡指标,为制定该省婴儿死亡率的卫生政策和医疗保健措施提供一定的理论依据。 【方法】 根据Rutstein等提出的可避免死亡指标,采用四川省与美国、本省城乡婴儿死因死亡率对比,计算相对危险度。 【结果】 四川省婴儿可避免死因为:败血症、肺炎、腹泻、新生儿破伤风、新生儿硬肿症、颅内出血、先天愚型、出生窒息、意外窒息、溺水和意外跌落。 【结论】 要降低本省婴儿死亡率,应加强可避免死因疾病的控制。     

421例萤石矿矽肺死因分析

目的　探讨萤石矿矽肺职工的死亡原因 ,为矽肺治疗提供依据。方法　对浙江东风萤石矿 1 963～ 2 0 0 0年矽肺职工的死亡资料作死因分析。结果　 37年间累计矽肺职工 82 8人 ,累计死亡 42 1人 ,死亡率 50 85 %。平均死亡年龄 54 60岁 ,因肺结核死亡年龄低于其他疾病 (t=5 0 8,P <0 0 0 1 ) ,随年代推移平均死亡年龄增加 (F =2 1 0 2 1 ,P<0 0 0 1 )。从死因构成看 ,全死因的前 3位分别为肺结核、矽肺、恶性肿瘤。随年代推移肺结核比例逐渐下降 ,而矽肺与恶性肿瘤死亡比例逐渐上升 ,90年代后 ,肺癌的上升趋势明显。结论　应继续加强巩固结核病防治 ,保护肺功能 ,进一步加强对恶性肿瘤尤其是肺癌的三早预防     

Employment grade differences in cause specific mortality. A 25 year follow up of civil servants from the first Whitehall study

STUDY OBJECTIVE: To test the hypothesis that the association between socioeconomic status and mortality rates cuts across the major causes of death for middle aged and elderly men. DESIGN: 25 year follow up of mortality in relation to employment grade. SETTING: The first Whitehall study. PARTICIPANTS: 18,001 male civil servants aged 40-69 years who attended the initial screening between 1967 and 1970 and were followed up for at least 25 years. MAIN OUTCOME MEASURE: Specific causes of death. RESULTS: After more than 25 years of follow up of civil servants, aged 40-69 years at entry to the study, employment grade differences still exist in total mortality and for nearly all specific causes of death. Main risk factors (cholesterol, smoking, systolic blood pressure, glucose intolerance and diabetes) could only explain one third of this gradient. Comparing the older retired group with the younger pre-retirement group, the differentials in mortality remained but were less pronounced. The largest decline was seen for chronic bronchitis, gastrointestinal diseases and genitourinary diseases. CONCLUSIONS: Differentials in mortality persist at older ages for almost all causes of death.     

2000～2004年西安市孕产妇死亡率及原因分析

目的通过孕产妇死亡资料的分析,为进一步降低孕产妇死亡率提供科学的依据。方法采用回顾性研究的方法,对2000～2004年来西安市孕产妇死亡情况进行分析。结果5年来西安市孕产妇死亡率为30.92/10万～50.51/10万。产科出血居死因顺位第一位,从2002年起,妊娠期高血压疾病所占死亡比例开始升高,2003年和2004年分别居死因第三位和第二位。结论西安市孕产妇死亡率与39/10万的目标仍有很大差距,要进一步降低全市孕产妇死亡率,必须加强孕产妇的保健管理。     

仪征市2006-2013年5岁以下儿童死亡率及死亡原因分析

目的分析江苏省仪征市5岁以下儿童死亡变化趋势和死亡原因,探讨降低5岁以下儿童死亡的干预措施。方法对2006-2013年5岁以下儿童死亡报告卡进行统计分析。结果 5岁以下儿童死亡率5.68‰,婴儿死亡率4.06‰和新生儿死亡率2.56‰,婴儿死亡占5岁以下儿童死亡比例为71.43%,新生儿死亡占婴儿死亡比率为63.08%。5岁以下儿童死因排在前5位是：溺水、先天性心脏病（先心病）、早产低体重、出生窒息、新生儿肺炎。5岁以下儿童死亡率与孕产妇系统管理率呈负相关,相关系数为-0.9221（P〈0.01）。结论加强对基层妇幼保健人员危急重症患儿救治等适宜技术培训,大力宣传与指导孕期保健知识,是降低5岁以下儿童死亡率、减少出生缺陷、提高人口素质的有力措施。     

2006—2010年金华市O～14岁儿童死因分析

目的：分析金华市近5年O～14岁儿童主要死亡原因,为制定干预措施提供依据。方法：对金华市2006—2010年O～14岁儿童死亡监测资料进行描述性分析。结果：0～14岁儿童年平均死亡率0．51‰,0岁组死亡率最高（5．94％。）,10～14岁组最低（O．15‰）,随着年龄的增长,死亡率下降。意外伤害、围生因素、先天畸形染色体异常是导致O～14岁儿童死亡的前3位原因,而意外伤害中引起儿童死亡的主要原因是溺亡和机动车交通事故。结论：针对0～14岁的主要死亡原因,在加强孕期检查和围生期保健工作的同时,应加强预防意外伤害健康教育,提高家长和儿童的伤害防范意识,有效降低儿童死亡率。     

Assessment of cancer clusters using limited cohort data with spreadsheets: Application to a leukemia cluster among rubber workers

This paper presents methods for initial investigation of occupational cancer clusters using limited data. Phase 1 of the methods developed uses basic data from the cluster of cases, but with cohort data limited to the size of the workforce at the plant. Phase 2 of the methods requires knowledge of the number of workers entering and leaving the workforce in each year. In the absence of data concerning age, the spreadsheet programs explore a variety of worker age distributions in synthetic cohort analyses. The methods were used to assess a cluster of six cases of leukemia with an average duration of work of 11 years in a tire manufacturing plant. It was concluded that the relative risk for the age range 30-50 was at least 7, providing further evidence for the association of leukemia with work in tire manufacture. The use of spreadsheet programs can provide a valuable first step assessment of apparent workplace cancer clusters.     

Adjustment for smoking, alcohol consumption, and socioeconomic status in the California Occupational Mortality Study.

This paper presents methods for adjusting for smoking, alcohol, and socioeconomic status in death certificate-based occupational mortality surveillance. The methods were applied in the California Occupational Mortality Study, a statewide study of rates based on 180,000 deaths and census estimates of occupations. For each occupation, levels of smoking, alcohol consumption, and socioeconomic status were estimated using National Health Interview Survey and U.S. Census data, and an empirical Bayes procedure was used to improve the stability of smoking and alcohol estimates for small occupations. Expected death rates for occupations were calculated by modeling rates as a function of age, smoking, alcohol, and socioeconomic status with Poisson regression. The effect of adjustment was usually moderate and in the expected direction, and the adjusted mortality ratios were generally closer to 1.0. Full data on agricultural occupations are presented for illustration.     

西安市2000～2008年孕产妇死亡趋势与原因探析

目的 探讨孕产妇死亡的变化趋势、影响因素、根本原因及其风险因素,以改善应对措施,确保母婴安全.方法 对西安市2000～2008年常住人口和流动人口中死亡的孕产妇资料,使用Excel数据库进行资料录入,利用SPSS 13.0软件包进行统计学分析.结果 西安市常住人口中孕产妇死亡率有逐年下降的趋势,平均为36.06/10万,2008年在2000年的基础上显著下降了57.28%(χ2=5.205,P=0.030<0.05);流动人口中的孕产妇死亡率平均为213.45/10万,流动人口中的孕产妇死亡率显著高于常住人口中的孕产妇死亡率(χ2=60.814,P=0.000<0.05);孕产妇死亡的前5位死因依次是产后出血、羊水栓塞、妊娠期高血压疾病、妊娠合并症、胎盘早剥;孕产妇产后出血的死亡率有逐年下降的趋势;死亡孕产妇中高危年龄占到17.24%,88.28%居住在农村地区;孕期仅有37.24%产前检查达到5次;死亡孕产妇的孕期系统保健管理率(χ2=410.648,P=0.000<0.05 )与住院分娩率(χ2=56.485,P=0.000<0.05)显著低于全市;孕产妇死亡率与孕期系统保健管理率(r =-0.719,P<0.05)、住院分娩率(r=-0.799,P<0.01)呈显著负相关;评审结果显示死亡孕产妇中有85.90%是可以避免或创造条件可以避免的死亡.结论 西安市常住人口中孕产妇死亡率已经达到<西安市妇女发展纲要(2001～2010年)>目标,但85.9%是可以避免的死亡.应不断提高孕产妇的早孕检查率、系统保健管理率、住院分娩率,加强高危孕产妇的监管,将可避免的孕产妇死亡降到最低水平.