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

Our plain-English summary of Use of death certificates in epidemiological studies, including occupational hazards: variations in discordance of different asbestos-associated diseases on best evidence ascertainment, by I.J. Selikoff, H. Seidman (American Journal of Industrial Medicine, 1992).

The study

• Authors: I.J. Selikoff, H. Seidman
• Journal: American Journal of Industrial Medicine
• Published: 1992;22(4):481-92
• Cited by: 40 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

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.

In plain English

This was a prospective study of all 17,800 men on the rolls of the asbestos insulation workers' union in the United States and Canada. They were followed from January 1, 1967, through December 31, 1986, and 4,951 died. For each death, the authors compared the death certificate cause with a "best evidence" cause based on available autopsy, surgical and clinical records. For about 10% of deaths no supplementary material was available, and the certificate served as best evidence. Mesothelioma, however, was accepted only after their own pathologists had reviewed slides. Agreement differed by disease. Of 1,008 death certificates listing lung cancer, 969 were confirmed. Of 458 verified mesotheliomas (173 pleural, 285 peritoneal), mesothelioma was mentioned on 287 certificates. Only 181 (39.5%) would have been found by investigating just the deaths properly coded as mesothelioma. For kidney cancer, death certificates identified 31 of 37 cases (83.8%). The authors concluded that discordance varies from disease to disease. In their view, death-certificate rates are therefore less suitable for studying specific diseases in occupational groups unless discordance for those diseases is known.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Prospective cohort study comparing death certificate causes of death with causes established by review of available clinical and pathology material ("best evidence")
• Who was studied: All 17,800 men on the rolls of the International Association of Heat and Frost Insulators and Asbestos Workers in the United States and Canada on January 1, 1967, followed through December 31, 1986; 4,951 deaths
• Exposure: Occupational asbestos exposure as insulation workers; the date of first insulation employment was used as the onset of exposure. The article does not name specific fiber types or give doses.
• Main results:
  • There were 4,951 deaths among the 17,800 insulators over 301,592.6 person-years of observation
  • Lung cancer: 969 of the 1,008 death certificates listing lung cancer were confirmed by best evidence. The authors described the overall discordance for lung cancer as limited, not much more than ten percent.
  • Best evidence identified 1,168 lung cancer deaths in total. The text states some were otherwise categorized on death certificates (139/1,168), but this figure is inconsistent with the article's own table (see text_problems).
  • Mesothelioma showed much greater discordance than lung cancer, especially peritoneal mesothelioma. Of the 458 histologically verified cases, 173 were pleural and 285 were peritoneal.
  • Among the 458 verified mesothelioma cases, some cancer was listed as the cause of death on 439 certificates (95.9%), and mesothelioma in some wording was mentioned on 287 certificates (62.7%)
  • Investigating only the 181 deaths properly coded as mesothelioma would have found 39.5% of the mesotheliomas; finding the other 60.5% required review of all deaths in the cohort
  • There were 30 additional death certificates designating mesothelioma that were not confirmed. Of the 24 with slides reviewed, 21 were lung cancer, 1 cancer of the pleura, 1 metastatic carcinoma and 1 Wegener's granulomatosis.
  • Kidney cancer: death certificates identified 31 of the 37 best-evidence cases (83.8%); 16.2% would have been missed without investigating everyone in the cohort
  • Discordance for kidney cancer was greater than for lung cancer but much less than for mesothelioma
• The authors' conclusion: The authors concluded that discordance between death certificates and best-evidence causes of death differs by disease: one level for lung cancer, others for pleural mesothelioma, peritoneal mesothelioma and kidney cancer. In their view, death-certificate death rates are suitable for total mortality but less suitable for specific diseases in occupational cohorts, unless there is information on discordance for the specific diseases of interest. They also concluded that additional data, such as best-evidence ascertainment, are needed.
• Limitations the authors state:
  • The authors had no information on work before insulation employment or on possible family contact exposure
  • For about 10% of deaths no supplementary material was available, so the death certificate cause was used as the best evidence
  • Six cases designated mesothelioma on death certificates could not be evaluated because the authors' pathologists had no chance to review slides
  • The best-evidence ratios for less common cancers were calculated for information only. They are not strictly comparable with expected rates based on death certificates, because the quality of ascertainment differs.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Death Certificate, Occupational Disease, Lung Cancer, Mesothelioma.

Related studies

• Death certificates in epidemiological studies, including occupational hazards: inaccuracies in occupational categories — I.J. Selikoff (1992)
• Influence of age at death on accuracy of death certificate disease diagnosis: findings in 475 consecutive deaths of mesothelioma among asbestos insulation workers and asbestos factory workers — I.J. Selikoff (1992)
• Estimation of the incidence of pleural mesothelioma according to death certificates in France — Y. Iwatsubo, M. Matrat, et al. (2002)
• Recovering missing mesothelioma deaths in death certificates using hospital records — V.S. Santana, E. Algranti, et al. (2018)
• Risk of stomach cancer associated with 12 workplace hazards: analysis of death certificates from 24 states of the United States with the aid of job exposure matrices — P. Cocco, M.H. Ward, et al. (1999)
• Validation of death certificates in asbestos workers — M.L. Newhouse, J.C. Wagner (1969)

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