Incorporating verbal autopsy into the civil registration and vital statistics system
Sampling strategies for verbal autopsy in national CRVS systems
Integrating automated VA into national CRVS systems should be done carefully and incrementally, ensuring that VA procedures and methods are producing reliable data for planning in a cost-effective manner. Full scale national implementation is not recommended until proposed VA procedures have been fully tested, and, where necessary, adjusted according to country needs and existing systems.
Sample registration (notification) systems (SRS) offer many advantages for assessing the applicability of proposed VA methods. Because the sites are, or should be, chosen to be a representative sample of the population, they will yield nationally representative data for planning at the same time as allowing a fine-tuning of VA procedures. Moreover, these systems yield data on current COD patterns in populations where otherwise such information would not be available for decades, pending the availability of sufficient physicians to certify causes of death. Third, the procedures for notification, diagnosis using VA, tabulation and use of data generated by SRS systems provide an excellent means for building essential data management, analysis and use capacity that is also required in CRVS systems.
Large, nationally representative SRS systems have been established in China, India and Indonesia and are under consideration elsewhere. Although such systems are not formally designed to ensure registration of births and deaths, they can be used as an efficient notification mechanism to inform birth and death registration offices about the occurrence of events in the sample population, and can be formally integrated into national CRVS systems. Their primary policy value, however, is their role in generating policy-relevant information on births, deaths and causes of death applicable to national populations.
Although there is increasing experience with sample vital event registration systems that include VA, this information has generally not been fully integrated with CRVS systems (China is an exception1) This should be kept in mind if SRS systems are being considered by countries. There remains a number of open questions and a lack of practical guidance for how to estimate the sample size required so that the number, age and sex distribution of VAs collected will provide valid and representative CSMFs of use to policy. It is also important to carefully consider how to stratify the population, using the most recent population census or similar national data source to address possible disparities in mortality patterns and epidemiologic risks among various ethnic, socioeconomic, and demographic (for example, urban or rural) groups. These population groups need to be adequately represented in any SRS system to ensure the data are representative of mortality conditions in the population.
Various sampling strategies are available to do so and are described in a short practical guidance document to assist countries to design sample registration/notification systems in order to scale up their exploratory VA experiences from demonstration phases to national CRVS-VA systems.
1 Zhou M, Yin P. The experience of China with the Disease Surveillance Point system. Chinese National Center for Disease Control and Prevention.
Jha P et al (2005). Prospective study of one million deaths in India: rationale, design, and validation results. PLoS ONE
Joshi R et al (2015). How much does a verbal autopsy based mortality surveillance system cost in rural India? PLoS ONE.
Liu S et al (2016). An integrated national mortality surveillance system for death registration and mortality surveillance, China. Bulletin of the World Health Organization.
Mahapatra P (2010). An overview of the sample registration system in rural India. Prince Mahidol Award Conference and Global Health Information Forum.
Pratiwi ED et al (2013). Development of an Indonesian sample registration system: a longitudinal study. The Lancet.