Comparing estimates of road traffic deaths and non-fatal road traffic injuries in Cambodia

Abstract

IntroductionTimely, accurate and detailed information about traffic injuries are essential for managing national road safety programmes. However, there is considerable under-reporting in official statistics of many low and middle-income countries (LMICs) and large discrepancies between estimates from the Global Burden of Disease (GBD) study and WHO’s Global Health Estimates (GHE). We compared all sources of epidemiological information on traffic injuries in Cambodia to guide efforts to improve traffic injury statistics.MethodsWe estimated the incidence of traffic deaths and injuries and household ownership of motor vehicles in Cambodia from nationally representative surveys and censuses. We compared findings with GDB and GHE estimates.ResultsWe identified seven sources for estimating traffic deaths and three for non-fatal injuries that are not included as data sources in GBD and GHE models. These sources and models suggest a fairly consistent estimate of approximately 3100 deaths annually, about 50% higher than official statistics, likely because most hospital deaths are not recorded. Surveys strongly suggest that the vehicle fleet is dominated by motorcycles, which is not consistent with GBD estimates that suggest similar numbers of motorcyclist and vehicle occupant deaths. Estimates of non-fatal injuries from health surveys were about 7.5 times official statistics and 1.5 times GBD estimates.ConclusionIncluding local epidemiological data sources from LMICs can help reduce uncertainty in estimates from global statistical models and build trust in estimates among local stakeholders. Such analysis should be used as a benchmark to assess and strengthen the completeness of reporting of the national surveillance system.

Estimates of road traffic deaths in Tanzania

“…We discuss the implications for estimating the true death toll in the country and elsewhere and efforts to improve national statistics. This study parallels a similar case study for Cambodia 14…”

“…Such differences often result in fairly large discrepancies between country-level estimates. In fact, changes in the modelling strategies between the various revisions of GBD alone result in large changes in estimates 14…”

Addressing discrepancies in estimates of road traffic deaths and injuries in Ethiopia

“…However, GBD estimates are used much less than GSRRS in global road safety advocacy partly because GBD methods and their effects on estimates are poorly understood. We believe country case studies that compare estimates with national data sources, such as this study of Ethiopia and similar work in other countries,8 9 can help build confidence in global statistical models.…”

“…This close correspondence between DHS-2016 and GSRRS-2018 estimates of road traffic deaths is surprising because GSRRS methods do not allow incorporating mortality data from surveys and the other most common sources of epidemiological information from LMICs (eg, verbal autopsies and incomplete death registers)30 31 that are routinely included in GBD. However, as we have recently shown even GBD does not include many key sources for road traffic deaths and injuries 7–9. The 2016 DHS in Ethiopia is an important example of such a data source because it is the only nationally representative source of information on road traffic injury mortality.…”

“…Therefore, we recommend that rather than using record-linkage/capture–recapture studies in countries where police under-reporting is suspected to be high, countries should collect nationally representative epidemiological data to assess under-reporting. This can be achieved, for instance, by including a road traffic injury module in a forthcoming national health survey as was done in the Ethiopian DHS in 2016 or by including questions in the national census or national verbal autopsy study, as has been done in Cambodia routinely for several years 8…”