Accuracy of industry and occupation on death certificates of electric utility workers: implications for epidemiologic studies of magnetic fields and cancer

A substantial epidemiologic literature has relied on occupation and industry information from death certificates to make inferences about the association of electric and magnetic field exposure with cancer, but the validity of the occupational data on death certificates is questionable. We compared occupation and industry information from death certificates to company work histories for 793 electric utility workers who died from brain cancer (n=143), leukemia (n=156), lung cancer (n=246, randomly sampled), and non-cancer causes (n=248, randomly sampled). Nearly 75% of death certificates correctly indicated utility industry employment and of those, 48% matched the longest held occupation derived from company work histories. Hence, only 36% matched on both industry and occupation. We computed odds ratios relating occupations involving magnetic field exposure to brain cancer and leukemia both for the occupation listed on the death certificate and for the longest-held occupation based on company records in order to examine the impact of exposure misclassification based on reliance on the death certificate information. For brain cancer, the odds ratio was 1.2 based on death certificates and 1.7 based on company work history, suggesting some attenuation due to misclassification. For leukemia, death certificate information yielded an odds ratio of 0.9, whereas company work histories yielded an odds ratio of 1.3. Although work histories are limited to the period of employment in a specific company, these data suggest that there is substantial misclassification in use of death certificate information on industry and occupation of utility workers, as found in other industries. The limited quality of occupation and industry information on death certificates argues against relying on such information to evaluate modest associations with mortality.     

The validity of cancer information on death certificates in Norway and the impact of death certificate initiated cases on cancer incidence and survival

BackgroundDeath certificates are an important source of information for cancer registries. The aim of this study was to validate the cancer information on death certificates, and to investigate the effect of including death certificate initiated (DCI) cases in the Cancer Registry of Norway when estimating cancer incidence and survival.MethodsAll deaths in Norway in the period 2011–2015 with cancer mentioned on the death certificates were linked to the cancer registry. Notifications not registered from other sources were labelled death certificate notifications (DCNs), and considered as either cancer or not, based on available information in the registry or from trace-back to another source.ResultsFrom the total of 65 091 cancers mentioned on death certificates in the period 2011–2015, 58,425 (89.8%) were already in the registry. Of the remaining 6 666 notifications, 2 636 (2 129 with cancer as underlying cause) were not regarded to be new cancers, which constitutes 4.0% of all cancers mentioned on death certificates and 39.5% of the DCNs. Inclusion of the DCI cases increased the incidence of all cancers combined by 2.6%, with largest differences for cancers with poorer prognosis and for older age groups. Without validation, including the 2 129 disregarded death certificates would over-estimate the incidence by 1.3%. Including DCI cases decreased the five-year relative survival estimate for all cancer sites combined with 0.5% points.ConclusionIn this study, almost 40% of the DCNs were regarded not to be a new cancer case, indicating unreliability of death certificate information for cancers that are not already registered from other sources. The majority of the DCNs where, however, registered as new cases that would have been missed without death certificates. Both including and excluding the DCI cases will potentially bias the survival estimates, but in different directions. This biases were shown to be small in the Cancer Registry of Norway.     

Deaths from rhesus haemolytic disease in England and Wales in 1977: accuracy of records and assessment of anti-D prophylaxis.

All the death certificates for deaths in 1977 where haemolytic disease of the newborn (HDN) was the principal, an antecedent, or a contributory cause were obtained from the Office of Population Censuses and Surveys (OPCS). The hospital notes of all 54 of the live-born cases and all of the 101 stillbirths were also obtained. The cause of the death indicated by the notes was compared with the cause and coding on the death certificate. In about a quarter of the cases death was not due to haemolytic disease of any type. The commonest errors arose because the International Classification of Diseases (8th edition) stipulates that hydrops without mention of cause should be coded as HDN and because stillbirths to rhesus-negative mothers tend to be attributed to rhesus HDN automatically. Though deaths from HDN may be overestimated in this way, they are also underestimated because rhesus disease, although mentioned on the certificate, is not selected as the underlying cause, which it may be. These cases were found through multiple coding of all the contributory causes of death, which OPCS performs on a 25% sample of all death certificates for research purposes. These two sources of inaccuracy tend to cancel each other out, but statistics from death certificates give a misleading picture of the efficacy of anti-D prophylaxis because anti-D can never prevent cases which are not in fact due to rhesus HDN. Most of the mothers studied had become immunised before anti-D became available, but in those who could have been treated 75% had not received prophylaxis. As this was a sample of deaths, however, it would not be accurate to extrapolate this high figure to the population at risk. Nevertheless, the organisation of prophylaxis is clearly deficient and should be remedied before providing antenatal anti-D to supplement postnatal treatment.     

Perinatal death recording: time for a change?

The new perinatal death certificate proposed by the World Health Organisation was examined in relation to existing measures for recording perinatal death statistics and also with regard to new information gathered. Present procedures appear to underestimate the number of perinatal deaths by roughly 10%, though late registrations may lower this figure slightly. The use of a minimum birth weight as the criterion for inclusion in perinatal statistics removed much of the uncertainty associated with definitions of live birth and stillbirth. The new certificate led to duplication of some information already recorded through birth notification yet failed to provide information on some other factors generally considered relevant to perinatal mortality. The format proposed for recording cause of death provided a more logical presentation of events. Standardizing birth information recorded on all infants, modifying death certificates, and developing efficient record-linkage schemes would be more valuable than introducing the WHO certificate. Useful interpretation of the meaning of the characteristics of infants dying in the perinatal period awaits these timely changes.     

LIVE BIRTH CERTIFICATES—Evaluation of Medical and Health Data in California

In a study of 1,609 single live births occurring in San Francisco County, the information on the birth certificate was compared with that on the hospital record to determine completeness and accuracy of the items reported on the certificate.Items such as color or race of mother, age of mother, birth weight and birth length of child were well recorded on the certificate and agreed with information found in the hospital record.Medical conditions were grossly underreported on the birth certificate. Conditions relating to the mother were more frequently recorded than those relating to the infant, but the birth certificates recorded less than one-fifth of all medical conditions of both mother and infant that were entered in the hospital records.Methods suggested for improving the quality of maternal and newborn morbidity information include revision of the medical section of the present certificates of live birth and fetal death and use of a precoded hospital record.     

医学检验专业实践教学改革与毕业生质量评价

目的：寻求医学检验专业教学改革新方案。方法：以我校检验专业2000、2001届毕业生为对照组,以2002、2003届毕业生为实验组,对实验组进行实践教学改革。毕业前分别进行综合实践技能考核,并对部分毕业生进行了追踪调查。结果：实验组的技能考核成绩明显高于对照组,毕业生质量明显提高。结论：实践教学改革有利于提高医学检验专业教学质量。     

Mortality rates in subjects with fetal alcohol spectrum disorders and their siblings

BACKGROUND: Our objective was to estimate the mortality rate in subjects with fetal alcohol spectrum disorders (FASD) and their siblings whose FASD status was unknown. METHODS: We used the state FASD Registry to link subjects with FASD to a North Dakota birth certificate. We were able to link 304 of 486 cases (63%). We used the birth certificates to identify the mother and children born to the mother (siblings). We then searched for death certificates for both the FASD cases and their siblings. We then calculated the annual and age‐adjusted mortality rates for the siblings of the Registry cases and compared them with mortality rates from North Dakota. RESULTS: The FASD case mortality rate was 2.4%, with a 4.5% mortality rate for their sibings, accounting for 14% of all deaths when compared to the North Dakota residents matched by age and year of death. The sibling deaths accounted for 21.5% of all cause mortality matched by age and year of death. The age‐standardized mortality ratios were 4.9 for the FASD cases and 2.6 for their siblings whose FASD status was unknown. CONCLUSIONS: Mortality rates for FASD cases and their siblings were increased and represent a substantial proportion of all cause mortality in North Dakota. Prevention of FASD may be a useful strategy to decrease mortality. Birth Defects Research (Part A), 2008. © 2008 Wiley‐Liss, Inc.     

Impact of using multiple causes of death codes to compute site-specific, death certificate-based cancer mortality statistics in the United States

Background: Cancer mortality statistics, an important indicator for monitoring cancer burden, are traditionally restricted to instances when cancer is determined to be the underlying cause of death (UCD) based on information recorded on standard certificates of death. This study's objective was to determine the impact of using multiple causes of death codes to compute site-specific cancer mortality statistics. Methods: The state cancer registries of California, Colorado and Idaho provided linked cancer registry and death certificate data for individuals who died between 2002 and 2004, had at least one cancer listed on their death certificate and were diagnosed with cancer between 1993 and 2004. These linked data were used to calculate the site-specific proportion of cancers not selected as the UCD (non-UCD) among all cancer-related deaths (any mention on the death certificate). In addition, the retrospective concordance between the death certificate and the population-based cancer registry, measured as confirmations rates, was calculated for deaths with cancer as the UCD, as a non-UCD, and for any mention. Results: Overall, non-UCD deaths comprised 9.5 percent of total deaths; 11 of the 79 cancer sites had proportions greater than 3 standard deviations from 9.5 percent. The confirmation rates for UCD and for any mention did not differ significantly for any of the cancer sites. Conclusion and impact: The site-specific variation in proportions and rates suggests that for a few cancer sites, death rates might be computed for both UCD and any mention of the cancer site on the death certificate. Nevertheless, this study provides evidence that, in general, restricting to UCD deaths will not under report cancer mortality statistics.     

Understanding and enhancing compliance with the second dose of hepatitis B vaccine: a cohort analysis and a randomized controlled trial

OBJECTIVE: To determine the predictors and extent of noncompliance with a second dose of hepatitis B vaccine and the effectiveness of a compliance enhancement strategy. DESIGN: Cohort analysis and randomized clinical trial. SUBJECTS: A total of 256 consecutive adults attending a sexually transmitted diseases clinic from October 1992 to July 1993 who were seronegative for hepatitis B virus and agreed to receive hepatitis B vaccination. SETTING: Hamilton, Ont. INTERVENTION: Subjects were followed up for 4 months. Those who did not return for the second dose of vaccine by 6 weeks after the first (2 weeks overdue) were randomly assigned to the enhanced intervention group (telephone and mail reminders) or the regular intervention group (mail reminder only). Subjects were considered noncompliant if they did not return for the second dose by 4 months after the first. RESULTS: The risk of not returning for the second dose of vaccine within 4 months after the first was strongly and linearly associated with level of education (p = 0.004). The noncompliance rate among those with less than a grade 10 education was 50%, grade 10-13 education 34%, some college education 15% and some university education 9%. In the randomized controlled trial the enhanced intervention group had twice the compliance rate of the regular intervention group (48% v. 25%; p = 0.008). Subjects with no postsecondary education were highly responsive to the enhanced intervention (relative risk 2.1; p = 0.02) compared with those with a higher level of education (relative risk 1.0; p = 1.0). CONCLUSION: Hepatitis B vaccine recipients with lower educational levels are at increased risk of noncompliance with the second dose of vaccine but are highly responsive to telephone reminders.     

Causes of Mortality for Indonesian Hajj Pilgrims: Comparison between Routine Death Certificate and Verbal Autopsy Findings

Background

Indonesia provides the largest single source of pilgrims for the Hajj (10%). In the last two decades, mortality rates for Indonesian pilgrims ranged between 200–380 deaths per 100,000 pilgrims over the 10-week Hajj period. Reasons for high mortality are not well understood. In 2008, verbal autopsy was introduced to complement routine death certificates to explore cause of death diagnoses. This study presents the patterns and causes of death for Indonesian pilgrims, and compares routine death certificates to verbal autopsy findings.

Methods

Public health surveillance was conducted by Indonesian public health authorities accompanying pilgrims to Saudi Arabia, with daily reporting of hospitalizations and deaths. Surveillance data from 2008 were analyzed for timing, geographic location and site of death. Percentages for each cause of death category from death certificates were compared to that from verbal autopsy.

Results

In 2008, 206,831 Indonesian undertook the Hajj. There were 446 deaths, equivalent to 1,968 deaths per 100,000 pilgrim years. Most pilgrims died in Mecca (68%) and Medinah (24%). There was no statistically discernible difference in the total mortality risk for the two pilgrimage routes (Mecca or Medinah first), but the number of deaths peaked earlier for those traveling to Mecca first (p=0.002). Most deaths were due to cardiovascular (66%) and respiratory (28%) diseases. A greater proportion of deaths were attributed to cardiovascular disease by death certificate compared to the verbal autopsy method (p<0.001). Significantly more deaths had ill-defined cause based on verbal autopsy method (p<0.001).

Conclusions

Despite pre-departure health screening and other medical services, Indonesian pilgrim mortality rates were very high. Correct classification of cause of death is critical for the development of risk mitigation strategies. Since verbal autopsy classified causes of death differently to death certificates, further studies are needed to assess the method’s utility in this setting.     

Death Certificates Underestimate Infections as Proximal Causes of Death in the U.S

Background

Death certificates are a primary data source for assessing the population burden of diseases; however, there are concerns regarding their accuracy. Diagnosis-Related Group (DRG) coding of a terminal hospitalization may provide an alternative view. We analyzed the rate and patterns of disagreement between death certificate data and hospital claims for patients who died during an inpatient hospitalization.

Methods

We studied respondents from the Health and Retirement Study (a nationally representative sample of older Americans who had an inpatient death documented in the linked Medicare claims from 1993–2007). Causes of death abstracted from death certificates were aggregated to the standard National Center for Health Statistics List of 50 Rankable Causes of Death. Centers for Medicare and Medicaid Services (CMS)-DRGs were manually aggregated into a parallel classification. We then compared the two systems via 2×2, focusing on concordance. Our primary analysis was agreement between the two data sources, assessed with percentages and Cohen''s kappa statistic.

Results

2074 inpatient deaths were included in our analysis. 36.6% of death certificate cause-of-death codes agreed with the reason for the terminal hospitalization in the Medicare claims at the broad category level; when re-classifying DRGs without clear alignment as agreements, the concordance only increased to 61%. Overall Kappa was 0.21, or “fair.” Death certificates in this cohort redemonstrated the conventional top 3 causes of death as diseases of the heart, malignancy, and cerebrovascular disease. However, hospitalization claims data showed infections, diseases of the heart, and cerebrovascular disease as the most common diagnoses for the same terminal hospitalizations.

Conclusion

There are significant differences between Medicare claims and death certificate data in assigning cause of death for inpatients. The importance of infections as proximal causes of death is underestimated by current death certificate-based strategies.     

Death certification and epidemiological research. Medical Services Study Group of the Royal College of Physicians of London.

The cause of death shown on 191 death certificates was compared with the cause indicated by the hospital case notes, the consultants'' opinions, and the necropsy findings. All 191 deaths occurred among medical hospital patients aged under 50. In 39 cases there was a major discrepancy between the two sources over the cause of death and in another 54 ther was a minor but epidemiologically important difference. Death certificates are not primarily intended for epidemiological research, but researchers often rely on them. This and other studies have shown, however, that death certificates are often inaccurate records of the cause of death--even coroner''s certificates issued after a coroner''s necropsy. The accuracy of death certificates might be improved if coroners consulted clinicians more closely and if senior hospital staff completed hospital death certificates.     

Cause‐specific mortality among older African‐Americans: Correlates and consequences of age misreporting

Abstract

This paper examines the quality of age reporting on death certificates of elderly African‐Americans by major causes of death. We utilize a sample of death certificates linked to early census records and to Social Security Administration records to establish a “true” age at death. We then examine the patterns, predictors, and consequences of age misreporting for major causes of death. We find a pattern of greater age misreporting among females, identify educational background as a key predictor of accurate age reporting, and show that mortality crossovers are eliminated for most causes of death when more accurate age data are used.     

Failure to deliver hepatitis B vaccine: confessions from a genitourinary medicine clinic.

OBJECTIVE--To audit hepatitis B immunisation of homosexual or bisexual men in a genitourinary medicine clinic. DESIGN--Retrospective case note review of all homosexual and bisexual men presenting to a genitourinary clinic as new patients during 12 months in 1988 and follow up review of notes to May 1990. SETTING--One department of genitourinary medicine, Middlesex Hospital. PATIENTS--758 homosexual or bisexual men, of whom 207 started a course of hepatitis B vaccine in 1988. Case notes were unavailable for one patient. MAIN OUTCOME MEASURES--The proportion of patients screened for hepatitis B virus markers, the proportion of susceptible patients immunised, the proportion completing the vaccine course, and the proportion rendered immune. RESULTS--25 men had been previously tested for hepatitis markers; of the 732 not previously tested, 440 (60.1%) were screened for hepatitis B markers. 207 (69%) of the 300 patients without hepatitis B serological markers started the vaccine course, and 141 (68%) completed it, with 75 (84%) of the 89 tested after immunisation being immune. An estimated 24% of susceptible new patients were rendered immune as a result of the immunisation policy. Patients who presented with a further episode of a sexually transmitted disease were more likely to have been screened (25% v 12%, p less than 0.0001) and immunised (31% v 18% p = 0.02); those known or found to be positive for HIV antibody were more likely to have been screened (23% v 14%, p = 0.047) but less likely to have been immunised (6% v 17%, p = 0.004). CONCLUSIONS--The major failure was that in not screening; failure to immunise patients found to be susceptible and failure of compliance with the vaccine course contributed. Non-response to the vaccine was of minor importance. Improvements in vaccine delivery are required. IMPLICATIONS--Other providers should be encouraged to review their performance.     

Pregnancy outcome of women exposed to azathioprine during pregnancy

BACKGROUND: Azathioprine (AZP) interferes with nucleic acid synthesis and is teratogenic in animals. In view of the paucity of information on the use of AZP during pregnancy we investigated this subject in a prospective, controlled, multicenter study. Our objective was too determine whether exposure to AZP during pregnancy increases the risk for major malformations and to determine the effect on pregnancy outcome. METHODS: Pregnant women on AZP who contacted one of seven teratogen information services were compared to a cohort of pregnant women who contacted two of the seven teratogen information services and took nonteratogenic treatments during their pregnancy. RESULTS: Follow-up was completed on 189 women in the AZP group and compared to 230 women in the control group. The rate of major malformations did not differ between groups with six neonates in each; the AZP rate was 3.5% and the control group rate was 3.0% (p = .775; OR 1.17; CI: 0.37, 3.69). The mean birth weight and gestational age were lower in the AZP group (2,995 g vs. 3,252 g [p = .001, difference of mean: 257, 95% CI: 106.3, 408.1] and 37.8 weeks vs. 39.1 weeks [p = .001, difference of mean: 1.3, 95% CI: .5, 2.0], respectively). The AZP group had more cases of prematurity (21.4% vs. 5.2% [p < .001; OR 4.0; 95% CI: 2.0, 8.06]) and low birth weight (23% vs. 6.0% [p < .001; OR 3.81; 95% CI: 2.0, 7.2]). CONCLUSIONS: These results suggest that AZP (50-100 mg/day) does not triple the rate of birth defects; however, it is associated with lower birth weight, gestational age, and prematurity. Larger studies are needed to confirm these observations.     

Problems in using birth certificate files in the capture-recapture model to estimate the completeness of case ascertainment in a population-based birth defects registry in New York State

BACKGROUND: The limitations and underlying assumptions of the capture-recapture methods have hindered their application in epidemiological settings, especially in evaluating the completeness of birth defects registries. This study explored the possibility of using birth certificates as the secondary data source in a simple two-source capture-recapture model to estimate the completeness of case ascertainment of the Congenital Malformations Registry (CMR) for selected major birth defects. METHODS: The CMR and the birth certificates were used as the primary and secondary sources, respectively. Children who were born in 1996-2001 and had selected major birth defects were identified from the two sources. The accuracy of the diagnoses was examined by comparing the individual birth defect categories of the children from the two sources. RESULTS: Discrepancies in birth defect categories in the two data sources and false positives in the birth certificates were the major problems encountered in estimating the completeness of the CMR using the simple two-source capture-recapture method. The estimated completeness for selected major birth defects was only about 71%. Stratified analyses resulted in relatively high estimated completeness for oral clefts (90%) and Down syndrome (88%). CONCLUSIONS Although the birth certificate data was not a good source for estimating the completeness of case ascertainment of the CMR using capture-recapture methods, the analyses provided reasonable estimates for some conditions that were relatively easy to identify and diagnose at birth, such as oral clefts and Down syndrome.     

Trends in mortality statistics in England and Wales with particular reference to AIDS from 1984 to April 1987

Death certification should be able to provide accurate data on the number of deaths due to AIDS as a basis for predicting future deaths from the syndrome. Trends in deaths from other causes may identify conditions that have not been recognised to be associated with HIV infection. Mortality statistics with reference to AIDS in England and Wales were completed from death certificates. Increases in deaths from selected causes likely to be associated with AIDS or HIV infection suggested that in some patients with HIV infection, AIDS was not stated on the death certificate or subsequently notified by the doctor who signed the certificate. From calculations of excess deaths between the beginning of 1985 and the end of April 1987, compared with 1984 at least 495 deaths possibly associated with HIV infection were estimated to have occurred among men aged 15-54 during that period. In 261 AIDS or HIV infection was stated on the original or amended death entry as the cause of death, and of these 198 were included in the estimated number of excess deaths.Accurate notification of the underlying cause of death and associated diseases is required for the precise monitoring of trends in mortality from AIDS and possible identification of unrecognised conditions associated with HIV infection.     

Mortality in neurofibromatosis 1: an analysis using U.S. death certificates

Although neurofibromatosis 1 (NF1) is a relatively common autosomal dominant condition, information about its effect on mortality is limited. We used Multiple-Cause Mortality Files, compiled from U.S. death certificates by the National Center for Health Statistics, for 1983 through 1997. We identified 3,770 cases of presumed NF1 among 32,722,122 deaths in the United States, a frequency of 1/8,700, which is one-third to one-half the estimated prevalence. Mean and median ages at death for persons with NF1 were 54.4 and 59 years, respectively, compared with 70.1 and 74 years in the general population. Results of proportionate mortality ratio (PMR) analyses showed that persons with NF1 were 34 times more likely (PMR=34.3, 95% confidence interval [CI] 30.8-38.0) to have a malignant connective or other soft-tissue neoplasm listed on their death certificates than were persons without NF1. Overall, persons with NF1 were 1.2 times more likely than expected (PMR=1.21, 95% CI 1.14-1.28) to have a malignant neoplasm listed on their death certificates, but the PMR was 6.07 (95% CI 4.88-7.45) for persons who died at 10-19 years of age and was 4.93 (95% CI 4.14-5.82) for those who died at 20-29 years of age. Similarly, vascular disease was recorded more often than expected on death certificates of persons with NF1 who died at <30 years of age (PMR=3.26, 95% CI 1.31-6.71 at age <10 years; PMR=2.68, 95% CI 1.38-4.68 at age 10-19 years; and PMR=2.25, 95% CI 1.46-3.32 at 20-29 years) but not in older persons. This study supports previous findings of decreased life expectancy for persons with NF1 and, within the limitations of death certificates, provides population-based data about NF1 morbidity and mortality that are useful to clinicians caring for patients with NF1.