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Improving the public health utility of global cardiovascular mortality data: the rise of ischemic heart disease
Published in Population Health Metrics, March 2011
In order to implement the most effective health policies, decision-makers require high-quality, cause-specific mortality data. However, the utility of mortality data is often limited by the use of nonspecific cause of death codes, such as those for heart failure. Because prevention, detection, and treatment efforts differ for different underlying causes of heart failure, it is important to know the root causes of the heart failure deaths in a population. New research by IHME demonstrates how the quality of mortality data can be improved by redistributing deaths attributed to heart failure to their underlying causes of death according to statistically derived redistribution proportions.
The study, Improving the public health utility of global cardiovascular mortality data: the rise of ischemic heart disease, used this empirical method to reassign a majority of the deaths coded to heart failure to ischemic heart disease, a disease characterized by reduced blood supply to the heart. The method provides better evidence on a major cause of death and ultimately will enable policymakers to make more informed decisions regarding priority health interventions and resource allocation and thus hone the global response to the rising cardiovascular epidemic.
Researchers found that 3.5% of the deaths in the dataset, which included 135 million deaths across 790 country-years, were coded to heart failure. For the adult age groups (15 to 49 years and 50 years and above), in both men and women, and in both developed and developing countries, the highest number of these heart failure deaths were reassigned to ischemic heart disease.
The revised mortality data show that ischemic heart disease becomes the top cause of death in several developed countries, including France and Japan, underscoring the significance of the cardiovascular epidemic in high-income countries. Furthermore, age-adjusted death rates increased for ischemic heart disease in low- and middle-income countries, such as Argentina and South Africa, demonstrating that the cardiovascular disease epidemic is growing in regions where public health efforts have historically focused on infectious diseases.
Chronic obstructive pulmonary disease (COPD) and hypertensive heart disease also made significant gains after heart failure redistribution. In the United States, COPD displaced Alzheimer’s disease to become the No. 3 cause of death in females. In Argentinean women, hypertensive heart disease moved from the 16th to the 6th leading cause of death after redistribution.
Using all available mortality data from the 10th version of the International Classification of Diseases (ICD-10) from the World Health Organization, the authors regressed deaths coded to heart failure with deaths coded to the recognized underlying causes of heart failure. The regression analysis was stratified by sex, age, and country development status to reflect demographic specificity. Researchers estimated the proportion of deaths coded to heart failure that should be redistributed to each target group based on the results of this regression model. The pre- and post-redistribution mortality datasets were then compared to assess the magnitude of the effect of redistributing heart failure.
The availability of high-quality, cause-specific mortality data is limited, even for countries with high vital registration coverage. The aim of this study was to improve the quality of mortality data to provide policymakers with better information to prioritize health interventions, using the heart failure cause of death code as a case study. This study is part of ongoing work by IHME to better understand the current state of population health so that policymakers can make the most informed decisions.
The use of heart failure as an underlying cause of death code obscures the true population causes of death, presenting a marked challenge to setting a health policy agenda that adequately addresses the needs of the population. In regions of the world where the health policy debate has concentrated almost exclusively on infectious diseases, such as sub-Saharan Africa, this method highlights the double burden of disease, in which communicable disease coexists with noncommunicable disease.
As electronic health records become increasingly utilized, safeguards should be considered to prevent the use of nonspecific codes in assigning causes of death. Furthermore, these results imply that health professionals should be provided with better diagnostic tools as well as professional education on the crucial role of death certification in defining health policies.
Citation: Ahern RM, Lozano R, Naghavi M, Foreman K, Gakidou E, Murray CJL. Improving the public health utility of global cardiovascular mortality data: the rise of ischemic heart disease. Population Health Metrics. 2011; 9:8.