Abstract
BACKGROUND: It is generally acknowledged that conventional estimates of the potential number of life years to be gained by elimination of causes of death are too generous. This is because these estimates fail to take into account the fact that those who are saved from the cause are likely to have one or more other conditions ("competing" causes of death), which may increase their risks of dying. It is unknown to what extent this introduces bias in comparisons of life years to be gained between underlying causes of death. The purpose of the study was to assess this bias. DATA AND METHODS: A sample of 5975 death certificates from the Netherlands, 1990, was coded for the presence of diseases that, according to a set of explicit rules, could be regarded as potential causes of death "competing" with the underlying cause. Logistic regression analysis was used to quantify age and sex adjusted differences between four main underlying causes of death (neoplasms, cardiovascular diseases, respiratory diseases, all other diseases) in prevalence of the six most frequent competing causes of death (neoplasms, ischaemic heart disease, cerebrovascular disease, other cardiovascular diseases, chronic obstructive lung disease, all other diseases). These prevalence differences were then used to revise conventional calculations of gains in life expectancy, by taking them to indicate differences in risk of dying from these competing causes after the underlying cause has been eliminated. RESULTS: The prevalence of competing causes of death is relatively low among persons dying from neoplasms as the underlying cause, about average among persons dying from cardiovascular diseases, and relatively high among persons dying from respiratory diseases. Taking this into account results in substantial decreases of potential life years to be gained by elimination of cardiovascular diseases and respiratory diseases, relative to the number of years to be gained by elimination of neoplasms. Specifically, while according to the conventional calculations the gain in life expectancy by elimination of cardiovascular diseases exceeds that for neoplasms by more than one year, in the revised calculations the number of life years to be gained is approximately equal. CONCLUSIONS: Despite its limitations, mainly relating to reliance on death certificate data, this study suggests that conventional estimates of differences between underlying causes of death in life years to be gained by elimination are seriously biased by ignoring the effects of competing causes. Specifically, the relative impacts of eliminating cardiovascular diseases and respiratory diseases, as compared with eliminating neoplasms, seem to be overestimated. The implications are discussed.
Full Text
The Full Text of this article is available as a PDF (105.8 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Beaglehole R. International trends in coronary heart disease mortality, morbidity, and risk factors. Epidemiol Rev. 1990;12:1–15. doi: 10.1093/oxfordjournals.epirev.a036048. [DOI] [PubMed] [Google Scholar]
- Bild D. E., Stevenson J. M. Frequency of recording of diabetes on U.S. death certificates: analysis of the 1986 National Mortality Followback Survey. J Clin Epidemiol. 1992 Mar;45(3):275–281. doi: 10.1016/0895-4356(92)90087-4. [DOI] [PubMed] [Google Scholar]
- CORNFIELD J. The estimation of the probability of developing a disease in the presence of competing risks. Am J Public Health Nations Health. 1957 May;47(5):601–607. doi: 10.2105/ajph.47.5.601. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chiang C. L. Competing risks in mortality analysis. Annu Rev Public Health. 1991;12:281–307. doi: 10.1146/annurev.pu.12.050191.001433. [DOI] [PubMed] [Google Scholar]
- Flaten T. P. Mortality from dementia in Norway, 1969-83. J Epidemiol Community Health. 1989 Sep;43(3):285–289. doi: 10.1136/jech.43.3.285. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Goldacre M. J. Cause-specific mortality: understanding uncertain tips of the disease iceberg. J Epidemiol Community Health. 1993 Dec;47(6):491–496. doi: 10.1136/jech.47.6.491. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Israel R. A., Rosenberg H. M., Curtin L. R. Analytical potential for multiple cause-of-death data. Am J Epidemiol. 1986 Aug;124(2):161–179. doi: 10.1093/oxfordjournals.aje.a114375. [DOI] [PubMed] [Google Scholar]
- Keyfitz N. What difference would it make if cancer were eradicated? An examination of the Taeuber paradox. Demography. 1977 Nov;14(4):411–418. [PubMed] [Google Scholar]
- Mackenbach J. P., Kunst A. E., Lautenbach H., Bijlsma F., Oei Y. B. Competing causes of death: an analysis using multiple-cause-of-death data from The Netherlands. Am J Epidemiol. 1995 Mar 1;141(5):466–475. doi: 10.1093/oxfordjournals.aje.a117449. [DOI] [PubMed] [Google Scholar]
- Mackenbach J. P., Kunst A. E., Lautenbach H., Oei Y. B., Bijlsma F. Competing causes of death: a death certificate study. J Clin Epidemiol. 1997 Oct;50(10):1069–1077. doi: 10.1016/s0895-4356(97)00165-0. [DOI] [PubMed] [Google Scholar]
- Manton K. G., Poss S. S. Effects of dependency among causes of death for cause elimination life table strategies. Demography. 1979 May;16(2):313–327. [PubMed] [Google Scholar]
- Prentice R. L., Kalbfleisch J. D., Peterson A. V., Jr, Flournoy N., Farewell V. T., Breslow N. E. The analysis of failure times in the presence of competing risks. Biometrics. 1978 Dec;34(4):541–554. [PubMed] [Google Scholar]
- Puffer R. R. New approaches for epidemiologic studies of mortality statistics. Bull Pan Am Health Organ. 1989;23(4):365–383. [PubMed] [Google Scholar]
- Steenland K., Nowlin S., Ryan B., Adams S. Use of multiple-cause mortality data in epidemiologic analyses: US rate and proportion files developed by the National Institute for Occupational Safety and Health and the National Cancer Institute. Am J Epidemiol. 1992 Oct 1;136(7):855–862. doi: 10.1093/aje/136.7.855. [DOI] [PubMed] [Google Scholar]
- Thom T. J., Epstein F. H., Feldman J. J., Leaverton P. E. Trends in total mortality and mortality from heart disease in 26 countries from 1950 to 1978. Int J Epidemiol. 1985 Dec;14(4):510–520. doi: 10.1093/ije/14.4.510. [DOI] [PubMed] [Google Scholar]
- Tsai S. P., Lee E. S., Hardy R. J. The effect of a reduction in leading causes of death: potential gains in life expectancy. Am J Public Health. 1978 Oct;68(10):966–971. doi: 10.2105/ajph.68.10.966. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Uemura K., Pisa Z. Trends in cardiovascular disease mortality in industrialized countries since 1950. World Health Stat Q. 1988;41(3-4):155–178. [PubMed] [Google Scholar]
- Wong O. A competing-risk model based on the life table procedure in epidemiological studies. Int J Epidemiol. 1977 Jun;6(2):153–159. doi: 10.1093/ije/6.2.153. [DOI] [PubMed] [Google Scholar]