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.     

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.     

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.     

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.     

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.     

Malignant melanoma in the printing industry

In an occupational mortality surveillance study, cause-specific mortality patterns by occupation and industry, among Rhode Island residents who died during the period 1968-78, were examined using the age-standardized proportionate mortality ratio (PMR) method. A noteworthy finding was an elevated PMR for malignant melanoma among white males in the printing industry (PMR = 460, observed deaths = 6, p less than .01). When the results of other epidemiologic studies are reviewed in aggregate, they are consistent with this finding. A wide variety of chemicals, some of which are known or suspected human or animal carcinogens, are used in the printing industry. There is also potential exposure to ultraviolet radiation. The hypothesis of a relationship between malignant melanoma and occupational exposures in the printing industry should be investigated further.     

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.     

广西三城市居民伤害死亡的流行病学特征分析

目的 了解广西壮族自冶区城市居民伤害死亡情况及对居民健康危害程度，为伤害的预防决策提供科学依据。方法 对三城市1997～2001年居民死亡资料按年龄和性别应用伤害标化死亡率时行分析。结果 三城市5年1～89岁居民伤害总死亡人数为3954人，男性占71，5％。近一半的伤害死亡者为25～49岁，机动车和运输事故有关的伤害最常见，溺水是15岁以下儿童的主要死因，尤其是男性儿童；跌倒是70岁以上年龄组主要的死因。三城市伤害标化死亡率随时间推移有增高趋势。结论 伤害已对该区三城市居民健康构成了严重的危害，应根据不同年龄段的人群，制定不同的伤害预防措施。     

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。     

苏州市2008-2013年围产儿死亡率变化趋势及影响因素分析

目的分析苏州市围产儿死亡率变化及相关因素,探索降低围产儿死亡率的综合措施。方法对2008-2013年苏州市围产儿死亡资料进行统计分析。结果 6年中苏州市围产儿平均死亡率为7.11‰,并呈逐年下降趋势;多胎妊娠的发生率逐年上升;产妇年龄〈20岁及〉34岁组的围产儿死亡率较高;多胎妊娠的围产儿死亡率高于单胎妊娠;围产儿死亡原因依次为胎儿先天异常、原因不明、脐带因素、母体因素、早产低体重。结论要降低围产儿死亡率,应加大宣传力度,全面做好婚前、孕前、孕期、产时、产后宣教,提供各阶段的服务;加强人员培训,及早发现异常,尽早处理;加强对助孕机构的监管,减少多胎妊娠的发生;做好围产儿死亡评审工作,提高医务人员综合救治水平。     

2014—2018年南山区居民恶性肿瘤死因及减寿分析

目的:了解2014—2018年深圳市南山区居民恶性肿瘤死因情况及潜在减寿影响,为制定和调整卫生策略提供依据。方法:根据国家死因登记报告系统的数据和人口学资料,对2014—2018年深圳市南山区居民死因监测资料进行分析。结果:2014—2018年深圳市南山区居民恶性肿瘤粗死亡率为37.08/10万,其中男性粗死亡率为40.96/10万,女性粗死亡率为32.70/10万。45岁以上年龄组恶性肿瘤死亡率随年龄的增大明显升高,深圳市南山区居民的前5位死因顺位依次是肺癌、肝癌、直肠癌和肛门癌、胃癌以及乳腺癌。南山区居民平均期望寿命为85.84岁,去除恶性肿瘤的影响,居民平均期望寿命分别将增加2.20岁。结论:恶性肿瘤死因中肺癌、肝癌占比较高,应当在生活中控制一些危险因素,特别是控烟和控制感染,提高人群对肿瘤的防治意识。     

2018年甘肃省定西市居民死亡原因及期望寿命分析

摘 要 目的 了解脑卒中患者运动自我效能及生活质量水平并探讨两者的相关性。方法 采用一般资料调查表、运动自我效能量表(ESES)和脑卒中影响量表(SIS)对福州市2所三甲医院202例脑卒中患者进行问卷调查。结果 脑卒中患者运动自我效能总得分为（30.72±2.94）分,生活质量总得分为（67.14±4.54）分,均处于中等水平;患者运动自我效能总得分与生活质量总得分及力气、情绪、交流、日常生活活动能力、移动能力和手功能6个维度得分均呈正相关关系(P<0.01)。结论 脑卒中患者运动自我效能与生活质量密切相关,提示医护人员可以通过提高脑卒中患者运动自我效能来促进其生活质量的提升。     

Death certificates in epidemiological studies, including occupational hazards: inaccuracies in occupational categories.

We compared death certificates for asbestos-associated diseases (mesothelioma, lung cancer, asbestosis) in two asbestos workers' cohorts. One (insulation workers) had current or recent employment and a strong, continuing union support system which gave them much information about the effects of asbestos exposure. The second cohort, asbestos factory workers, had no such advantage. The factory had closed almost 30 years before, and its workers had dispersed into many areas of the state and nation. Accuracy of medical diagnosis was comparable in the two groups, but occupational listings were not. Three-quarters of the insulators' death certificates told of asbestos work, while virtually none of the factory workers' certificates provided such information, even for deaths of mesothelioma and asbestosis. The data indicate that disease categories, based on medical and pathological diagnoses, at least for asbestos-associated disease, tend to be accurate. Attempts to identify groups at risk by sorting occupational categories can give variable results, good for those with current exposures, much less satisfactory for those with long-past occupational exposures.     

Methodology in industrial health studies: Social security disability data and the medical care system

This paper is directed at the exploration and development of the Social Security data, in the ascertainment and evaluation of industrial health effects. The focus of the study is on disability data, as a national uniform means to identify illnesses and disease that occurred prior to death, that were not recorded on the death certificates. A cohort of employees of an industrial company was processed through the Social Security System to simultaneously identify the disability and death claims that were filed. The total number of white males that filed disability claims was 1,333 and for white females 278. The total number of claims filed for the white males was 1,734 and for white females 382. Comparisons were made of all causes of disability with all causes of death for white males and white females. A remarkably high percentage of causes of disability were not recorded or available by death certificate for ICD categories of diseases and specific cancer sites. The study also demonstrated that disability data contribute significantly to the confirmation of the diagnosis for the cancer sites. The development of the methodology linking Social Security data on disability, medical care, and mortality with industrial medical and environmental exposure data in epidemiological studies is discussed. © 1993 Wiley-Liss, Inc.     

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.     

2012年达州市全死因监测信息分析

目的了解达州市人群死亡原因及其相关因素。方法对2012年居住在达州市境内的死亡居民进行调查并填写《死亡医学证明书》,推断根本死因,及时录入,进行统计分析。结果全市全年监测人口6 906 332人,报告死亡36 705人,粗死亡率5.31‰,标化死亡率4.28‰。其中男性22 474人,粗死亡率6.18‰,标化死亡率4.91‰;女性14 231人,粗死亡率4.36‰,标化死亡率3.52‰。死因前5位为：心脑血管疾病、肿瘤、呼吸系统疾病、伤害、消化系统疾病。结论心脑血管疾病、肿瘤和呼吸系统疾病等是威胁达州市人民生命的主要原因。