Experiences with linked birth and infant death certificates from the NIMS project

The National Infant Mortality Surveillance (NIMS) project aggregated data provided by 53 vital statistics reporting areas--50 States, New York City, the District of Columbia, and Puerto Rico (subsequently called States)--from their files of linked birth and death certificates and compared individual States' total infant mortality experiences for the 1980 birth cohort by age at death, race, birth weight, and plurality. Therefore, it was essential to achieve maximum uniformity among the separate data sets and to specify when this uniformity could not be obtained. In working with these multiple sources, we identified five key issues that relate to data from linked birth and death certificates: Variations in definitions of variables are often embedded in data that have been gathered from several independent sources. (For NIMS, the sources were 53 reporting areas and the National Center for Health Statistics.) Variations in States' linking procedures--these are based on an individual State's primary purpose for linking the data--affect the completeness and comparability of the 1980 resident birth cohorts used for NIMS. Variations in the recording of some pregnancy outcomes as fetal deaths or live births are known to be a problem in vital statistics data that particularly affects data for events among infants weighing less than 500 g at birth. Ambiguities occur frequently in unknowns or zero values. For NIMS this effect was most pronounced for the pregnancy history variables. Examination of the values reported for unknown or zero categories helps in uncovering problems with and improving quality of data.(ABSTRACT TRUNCATED AT 250 WORDS)     

Identification of cases of sudden infant death syndrome from death certificates.

A method is proposed for identification of cases of sudden infant death syndrome (SIDS) from information available on death certificates. Deaths at ages between 7 days and 2 years, referred to a coroner, having certain specified causes of death codes, identified 160 of 169 cases of SIDS confirmed as such by a pathologist. The sensitivity of the method was 94% and the specificity was 97%.     

Using linked birth and infant death files for program planning and evaluation: NIMS workshop lessons

Health planners should base program decisions on the best information available. Combining information from different sources can be valuable in identifying problems--the essential first step in program planning. To facilitate this process, a workshop was conducted during the National Infant Mortality Surveillance Conference in Atlanta, GA. Maternal and child health directors explored the use of linked birth and infant death data for program planning and evaluation. Linked birth and infant death certificate files permit evaluation of infant mortality by birth weight and other infant and maternal characteristics, thus providing more detailed information than birth or death certificates alone. An assessment of the birth weight distribution of live births, birth weight specific-mortality risks, distribution of deaths by birth weight, and birth weight-specific causes of death can help identify problems in the childbearing population and with the delivery of health services. Once the infant health problems are defined clearly, the selection and delivery of services can be better targeted and evaluated for the reduction of these problems.     

Overview of the National Infant Mortality Surveillance (NIMS) project

A slowdown in the decline of infant mortality in the United States and a continuing high risk of death among black infants (twice that of white infants) prompted a consortium of Public Health Service agencies, in collaboration with all states, to develop a national data base of linked birth and infant death certificates for the 1980 birth cohort. This project, referred to as National Infant Mortality Surveillance (NIMS), provides neonatal, postneonatal, and infant mortality risks for blacks, whites, and all races in 12 categories of birthweights. Tabulations were requested for infants born in single and multiple deliveries. For single-delivery births, tabulations included birthweight, age at death, race of infant, and each of these characteristics: infant's live-birth order, sex, gestation, type of delivery, and cause of death; and mother's age, education, prenatal care history, and number of prior fetal losses at greater than or equal to 20 weeks' gestation. An estimated 95% of eligible infant deaths were included in the NIMS tabulations. Analyses have focused on various components of infant mortality, including birthweight distribution of live births, neonatal mortality, and postneonatal mortality. The most important predictor for infant survival is birthweight; survival increases exponentially as birthweight increases to its optimal level. The nearly twofold higher risk of infant mortality among blacks than among whites was related to a higher prevalence of low birthweights, to higher mortality risks in the neonatal period for infants with birthweights of greater than or equal to 3,000 g, and to higher mortality during the postneonatal period for all infants, regardless of birthweight. Moreover, the black-white gap persisted for infants with birthweight of greater than or equal to 2,500 g, regardless of other infant or maternal risk factors.     

A comparison of occupational data from death certificates and interviews

A comparison was made of the occupational data reported on the death certificates of 586 men with their employment history obtained by interviews. Agreement was assessed for 19 occupational and 14 industrial categories of usual employment, with the highest levels of concordance (greater than or equal to 80%) found for agricultural, medical, and public administration activities. Between the two sources of information, there was overall agreement of 56% for usual occupation and 51% for usual industry of employment. Concordance was highest among the 68 self-respondents (usual occupation 66%; usual industry 53%). Among the 518 surrogates, spousal agreement was highest (58% for occupation and 51% for industry). For other surrogate types, agreement was 49% for both industry and occupation. Agreement varied by duration of employment and by level of education, with concordance tending to increase as length of employment and educational attainment rose. These relationships remained when examined by respondent type. Evaluation of agreement levels by age and other study subject characteristics showed little effect on concordance. Review of verbatim data from the interviews and death certificates revealed that most disagreements could be attributed to coding problems caused by vague or misleading information on the death certificates, although some disconcordance was due to uncodable and missing information in the interview history. Based on results from this and prior studies, the value of occupational data derived from death certificates in epidemiologic studies may be limited, although the addition of explicit instructions on the death certificate itself may aid in providing more useful and complete information for usual employment.     

Comparison of occupation and industry information from death certificates and interviews

Information on occupation and industry obtained via an interview prior to death was compared to occupation and industry on the death certificate of 184 colon cancer patients in Utah. The data were coded blindly using a five-digit code. Overall, agreement in the five-digit codes was found for 63 per cent. The industry codes agreed for 67 per cent of the individuals, and the occupation was identical for 68 per cent. Agreement by subjective evaluation of the two data sources, disregarding the five-digit codes, was 73 per cent. There were no differences in agreement of the five-digit codes by age, sex, and county of residence. The number of years worked at the job given by interview was related to agreement. Misclassification occurred in a random manner. It is concluded that the use of death certificates to study the association of occupation and disease is most appropriate for pilot studies.     

A study of selected death certificates from three Dublin teaching hospitals

One hundred death certificates were compared over two time periods with the corresponding autopsy reports on the cases to ascertain if the causes of death from the two sources were similar. There was poor concordance between the two and it seems likely that reasons for requesting an autopsy did not extend to using the information to complete the death certificates. There were 55 errors on 45 certificates, and 19 certificates were so inaccurate as to warrant a change in the underlying cause of death. In only 10 cases was the certificate signed before the autopsy report was available; however, should clinicians have wished to add autopsy findings to the certificate later, there is no facility on the Irish death certificate to do so. A revision of the format of the certificate is recommended. An examination of death certificates from varied medical sources would be welcome to see if the serious errors identified in this study are more widespread.     

Misclassification of childhood homicide on death certificates

Suspect classification of homicide deaths of Connecticut residents under 20 years of age was noted for 29 percent of cases examined. Misclassification was attributed to incomplete or erroneous information recorded on the death certificates, rather than errors in the designation of ICD-9 homicide codes. The results have important implications in the interpretation of vital statistics when homicide is listed as the cause of death and underscore the value of record linkage systems.     

Validation of death certificates in asbestos workers

Newhouse, M. L., and Wagner, J. C. (1969).Brit. J. industr. Med.,26, 302-307. Validation of death certificates in asbestos workers. The Registrar General has supplied the certified cause of death of 436 past workers in an asbestos factory. An attempt was made to follow up the 301 (69%) deaths which had occurred in hospital or had been the subject of an inquest or coroner's post-mortem examination. Necropsy reports were obtained for 158 (52%) of this group and histological material was reviewed in 84 (28%). The additional information, particularly that obtained from review of the histology, led to the revision and extension of the diagnosis suggested by the certified cause of death in a number of cases. The incidence of carcinoma of the bronchus had not been grossly underestimated, four additional tumours of this type were identified by scrutiny of the necropsy reports, and a further four by review of histological sections. The incidence of mesothelial tumours was underestimated, endothelioma or mesothelioma was the certified cause of death in four of the series, and a further 15 mesotheliomata were identified by review of histological material. Five patients with pleural mesotheliomata had been certified as dying of carcinoma of the lung or pleura. Ten deaths from peritoneal mesotheliomata had been attributed either to carcinomatosis without mention of a primary tumour or to cancer of the gastro-intestinal tract. Lung sections were submitted for review in 67 of the series; some degree of asbestosis was found in all but seven. Asbestosis graded as either moderate or severe was found in all the confirmed cases of carcinoma of the lung.     

Causes of death in Minamata disease: analysis of death certificates

Summary The causes of death in Minamata disease were analyzed and compared with those of control subjects. Of the 1422 Minamata disease patients in the Kumamoto Prefecture, 378 had died by the end of 1980. Of these 378, the first death occurred in 1954 with a peak incidence in 1956 when Minamata disease was officially reported for the first time. The number of deaths increased rapidly after 1972 with a second peak in 1976. The male: female ratio was 1.8: 1 and the mean age-at-death was 67.2 years (SD = ± 18.65). The mean age-at-death was younger in the cases of the initial outbreak than in those recently. There were, on the average, 2.8 causes of death per person. Of these cases, 157 (41.5%) had Minamata disease indicated on the death certificate, though 64 (16.9%) had Minamata disease coded as the underlying cause. Minamata disease and the noninflammatory diseases of the central nervous system (CNS) were the main underlying causes of death between 1954 and 1969, while, in the multiple cause data, pneumonia and non-ischemic heart disease were the most prevalent. Cerebrovascular diseases (18.0%) were the main underlying causes of death followed by malignant neoplasms (14.7%), cardiovascular diseases (14.1%) and Minamata disease (14.1%) in 1970 or later, while cardiovascular diseases (18.6%), Minamata disease (14.5%), cerebrovascular diseases (10.4%) and malignant neoplasms (7.1%) were the major multiple causes of death. As compared with the control, the proportions of deaths due to noninflammatory diseases of CNS and pneumonia were higher in the initial outbreak. Although the difference in the causes of death was less apparent recently, malignant neoplasms and hypertensive diseases tended to be lower. These results suggest that there is a need for a long-term follow-up of Minamata disease patients. The data also show the potential value of multiple causes of death coding in analyses of mortality.     

白银市2003～2010年婴儿死亡分析

目的:根据白银市2003～2010年婴儿死亡的调查统计资料,对婴儿死亡率的变化及其主要死因进行统计分析,为确定妇幼保健工作的重点与对策提供参考依据。方法:根据甘肃省5岁以下儿童死亡监测方案,利用全市5个县区5岁以下儿童死亡监测点2003～2010年儿童死亡监测资料中婴儿死亡相关资料进行统计、分析。结果:2003～2010年来全市婴儿死亡率下降明显,但农村婴儿死亡率明显高于城市;2003～2008年婴儿前3位死因顺位为肺炎、出生窒息、早产和低出生体重;其中肺炎、早产低出生体重死亡率下降明显,出生窒息死亡率下降不明显,2009～2010年婴儿前3位死因顺位为出生窒息、早产和低出生体重、先天性心脏病。先天性心脏病、其他先天异常等出生缺陷死因顺位上升。婴儿死亡构成中,新生儿占84.60%,其中早期新生儿占69.57%。结论:降低新生儿死亡率是降低婴儿乃至5岁以下儿童死亡率的关键。儿童保健工作的重点应放在农村,应加大对农村及边远贫困地区的妇幼卫生投入,加强农村三级妇幼卫生网络和卫生服务能力建设,促进城乡间协调发展;重视先天异常的预防、提高其检测水平。     

Causes of death in Huntington disease as reported on death certificates

Huntington disease (HD) is a late onset autosomal dominant neurological disorder. Two hundred fifty-three death certificates of HD-affected individuals from four midwestern states were examined to determine the completeness of reporting HD on the death certificates. Overall, 66% of death certificates indicated HD as a primary or contributory cause of death. There was significantly better reporting on more recent death certificates, but even since 1979, 16% did not report HD. The implications to those researching HD family histories and to the accuracy of mortality rates are discussed.