Background In rural China, mortality surveillance data may be an alternative to primary data collection in clinical trials; SmartVA (verbal autopsy) is also a potential alternative for endpoint adjudication. The feasibility and validity of both need to be assessed.
Methods We used mortality data from the first 24 months of the China Salt Substitute and Stroke Study (SSaSS) trial and assessed the agreement between (1) mortality surveillance data and face-to-face visits for fact of death; (2) mortality surveillance data and SSaSS adjudication for causes of death; (3) SmartVA and SSaSS adjudication for causes of death; (4) cause-specific mortality fraction of different methods. Face-to-face visits and SSaSS adjudication were taken as reference methods. The agreement was measured by sensitivity, specificity and positive predictive value (PPV) across different 10th Revision of International Statistical Classification of Diseases chapters.
Results One thousand three hundred and sixty-five deaths were included. Mortality surveillance data had 82% sensitivity for fact of death and 81% sensitivity for causes of death, with substantial variances across different disease types and reasonable quality for circulatory death (91% sensitivity and 94% PPV). The sensitivity of SmartVA for causes of death was 61%, with reasonable quality for deaths of external causes of morbidity (90% sensitivity). The leading causes of death from different sources were the same with some variances in the fractions.
Conclusion Using mortality surveillance data for fact of death in clinical trials need to account for under-reporting. A face-to-face visit to all participants at the completion of trials may be warranted. Neither mortality surveillance data nor SmartVA provided valid data source for endpoint events.
- outcome research evaluation
- randomised trials
- death certification
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LH and JY are joint first authors.
Twitter @Huang_LP, @JieYu43856396, @BruceNeal1, @XuejunYin, @Dr_WuJ, @rohinajoshi, @MaoyiT
Deceased Professor Jingpu Shi deceased on 27 October 2020.
Contributors LH: software, formal analysis, investigation, data curation, writing—original draft, Visualisation. JY: data curation, project administration. BN: conceptualisation, methodology, writing—review and editing, supervision, funding acquisition. YL: investigation, data curation, project administration. XY: investigation, data curation, project administration. JH: writing—review and editing. YW: conceptualisation, methodology, writing—review and editing, funding acquisition. LLY: conceptualisation, Methodology, writing—review and editing. ZH: supervision, project administration. RJ: writing—review and editing. JS: investigation, supervision, resources. XF: investigation, supervision, resources. JZ: investigation, supervision, resources. YZ: investigation, supervision, resources. RZ: investigation, supervision, resources. BZ: investigation, data curation, project administration, supervision. ZL: investigation, data curation, project administration, supervision. JS: investigation, data curation, project administration, supervision. YZ: investigation, data curation, project administration, supervision. YY: investigation, data curation, project administration, supervision. S-AP: writing—review and editing. ZC: writing—review and editing. MT: investigation, supervision, project administration, writing—review and editing, funding acquisition.
Funding The SSaSS trial is funded by Australian National Health and Medical Research Council (Grant ID: APP1049417 & APP1164206). BN is supported by an NHMRC Principal Research Fellowship (APP1106947). JHW is supported by a UNSW Scientia Fellowship. LH, BN and JHW are researchers within a National Health and Medical Research Council Centre for Research Excellence in reducing salt intake using food policy interventions (APP1117300). RJ is supported by an NHF Future Leader Fellowship (APP 102059).
Competing interests After 24 months, salt substitute has been provided by Jiangsu Sinokone Technology for free to the SSaSS trial.
Patient consent for publication Not required.
Ethics approval Both the University of Sydney Ethics Committee and the Peking University Institutional Review Board issued ethical approvals.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request. These data come from an ongoing clinical trial and can only be shared with a reasonable request.
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