Prospective Study of One Million Deaths in India: Rationale, Design, and Validation Results

Abstract

BackgroundOver 75% of the annual estimated 9.5 million deaths in India occur in the home, and the large majority of these do not have a certified cause. India and other developing countries urgently need reliable quantification of the causes of death. They also need better epidemiological evidence about the relevance of physical (such as blood pressure and obesity), behavioral (such as smoking, alcohol, HIV-1 risk taking, and immunization history), and biological (such as blood lipids and gene polymorphisms) measurements to the development of disease in individuals or disease rates in populations. We report here on the rationale, design, and implementation of the world's largest prospective study of the causes and correlates of mortality.Methods and FindingsWe will monitor nearly 14 million people in 2.4 million nationally representative Indian households (6.3 million people in 1.1 million households in the 1998–2003 sample frame and 7.6 million people in 1.3 million households in the 2004–2014 sample frame) for vital status and, if dead, the causes of death through a well-validated verbal autopsy (VA) instrument. About 300,000 deaths from 1998–2003 and some 700,000 deaths from 2004–2014 are expected; of these about 850,000 will be coded by two physicians to provide causes of death by gender, age, socioeconomic status, and geographical region. Pilot studies will evaluate the addition of physical and biological measurements, specifically dried blood spots.Preliminary results from over 35,000 deaths suggest that VA can ascertain the leading causes of death, reduce the misclassification of causes, and derive the probable underlying cause of death when it has not been reported. VA yields broad classification of the underlying causes in about 90% of deaths before age 70. In old age, however, the proportion of classifiable deaths is lower. By tracking underlying demographic denominators, the study permits quantification of absolute mortality rates. Household case-control, proportional mortality, and nested case-control methods permit quantification of risk factors.ConclusionsThis study will reliably document not only the underlying cause of child and adult deaths but also key risk factors (behavioral, physical, environmental, and eventually, genetic). It offers a globally replicable model for reliably estimating cause-specific mortality using VA and strengthens India's flagship mortality monitoring system. Despite the misclassification that is still expected, the new cause-of-death data will be substantially better than that available previously.

Methodological trends in studies based on verbal autopsies before and after published guidelines

“…17,18 The establishment of an international network of researchers involved in conducting verbal autopsy projects may facilitate the design of future studies, although it would clearly be impossible to see to it that they were all performed within the framework of such a group. More systematic interaction between international collaborations, such as the INDEPTH Network, 10 the Adult Morbidity and Mortality Project, 11 India's Sample Registration System's prospective study 19 and the Sample Vital Registration with Verbal Autopsy 14 initiative, might be one practical way of enhancing the way verbal autopsy studies are conducted. A recent publication by WHO, representing one more effort to set international standards for verbal autopsy methods, is a positive step forward but unlikely to suffice in and of itself.…”

Cardiovascular Risk and Events in 17 Low-, Middle-, and High-Income Countries

“…The patterns were similar among persons with prevalent cardiovascular disease. 14 The frequency of coronary revascularization (either coronary-artery bypass grafting or percutaneous coronary intervention) was highest in high-income countries, intermediate in middle-income countries, and lowest in low-income countries.…”

Stillbirths: Where? When? Why? How to make the data count?

“…77,82 Novel approaches are needed to record pregnancies and outcomes accurately; for example, in India, sentinel surveillance sites are used. 83 In view of the large diff erences in stillbirth rates in urban versus rural residences, ethnic origins, and socioeconomic metrics, data for programme design and tracking need to be as local and specifi c as possible. Even in high-income settings, there are major inequalities in stillbirth rates.…”