Evaluation of the quality of cause of death statistics in rural China using verbal autopsies

Abstract

BACKGROUND: Death registration systems in rural China are in a developmental stage. The Disease Surveillance Points (DSP) system provides the only nationally representative information on causes of death. In this system, there are no standard procedures or instruments for ascertaining causes of death; hence available statistics require careful evaluation before use. AIM: To assess the reliability of data from the DSP. METHODS: 14 DSP sites were selected through stratified sampling, enrolling 2482 deaths registered during June-November 2002. Defined verbal autopsy (VA) procedures were used to derive underlying causes of death. kappa Measures of agreement between VA and registered diagnoses were computed. VA diagnoses were used as references to compute sensitivity and positive predictive values. Finally, patterns of cause-specific discordance between the two data sources were studied. RESULTS: kappa Scores indicate only moderate agreement for chronic obstructive pulmonary disease (COPD) and ischaemic heart disease (IHD). The results also suggest that COPD is undercounted in registration data. A significant degree of cross attribution of cause was found between the two data sources. Overall, the VA was successful in limiting deaths with ill-defined causes to <10%. CONCLUSIONS: Diagnoses based on structured symptom questionnaires in the VA approach seem plausible and reliable as compared with lay-reported diagnoses in registration data. Concerns with attribution of cause of death due to COPD, IHD and tuberculosis in registration data suggest caution in their use for research and health programme purposes. The VA methods tested in this study offer promise for implementation in the routine registration system.