Estimating mortality using data from civil registration: a cross-sectional study in India.

Introduction Vital statistics are essential for tracking population dynamics, assessing health risks and evaluating health programmes. (1) In India, a national civil registration and vital statistics system --hereafter called the vital statistics system--is still under development. Estimates of mortality are based on alternate data sources--e.g. censuses, the sample registration system and specific projects. (2) Fragmentary data from such sources have been used recently to derive national estimates of mortality by age, sex and cause. (3-5) Inconsistency between estimates has hampered the evaluation of burdens posed by malaria, human immunodeficiency virus and road traffic collisions. (6-8) Before the introduction of the Registration of Births and Deaths Act in 1969, registration was non-uniform across states in India. The current system is supported by a national agency --the Office of the Registrar General of India- and registrars at state and local level. (9) The accuracy of the system, particularly in relation to cause of death, is limited. (10) In 1964-1965, the Office of the Registrar General introduced the sample registration system--as a separate entity from the vital statistics system--to measure fertility and mortality rates at national and state level in both urban and rural areas. In 2013, the sample registration system covered 7597 primary registration units with a combined population of 7.52 million. (11) In urban areas, the Registration of Births and Deaths Act of 1969 requires attending physicians to certify causes of deaths under the medical certification of cause of death scheme (10)--hereafter called the certification scheme. Although this scheme's coverage has gradually expanded over the last four decades, it remains patchy. (12) Between 1962 and 1999, causes of rural deaths were investigated in several surveys implemented by the Office of the Registrar General in collaboration with state health ministries. (13) In selected primary health centres, paramedical staff used disease-specific algorithms and a structured questionnaire on symptoms and signs to assign causes of death. The job of ascertaining causes of deaths in rural areas was transferred to the sample registration system in 1999. (13) Since then, the sample registration system has piloted verbal autopsy procedures and reported national summaries of causes of death as part of the Million Deaths Study. (14,15) Each year, this system captures barely 0.5% of the estimated deaths in India. The current sample is sufficiently powered to measure infant mortality reliably but is inadequate to provide accurate measures of child, maternal or adult mortality or life expectancy at state or district level. Given its nationwide coverage, a strengthened vital statistics system could meet the growing needs for detailed, timely and reliable data on mortality. Therefore, we investigated the system's design and functional status to facilitate the systems development into an accurate and reliable source of mortality data. Methods We used several sources to assess the design of the vital statistics system and to analysis of broad characteristics of the system's performance at national and subnational level (Box 1). (16-25) The quality of coverage was assessed in terms of the completeness of death registration and the quality of the recorded causes of death. The completeness of death registration for individuals aged at least six years at time of death was estimated by two methods: (i) using the number of deaths reported to the vital statistics system (18) and the Brass growth balance indirect demographic technique; (26) and (ii) applying the sample registration system's state-level mortality rates for 201111 to the state populations recorded in the 2011 census, to estimate the total mortality at national scale (the denominator). (19) The number of deaths registered in the civil registration system is the numerator. …