Concordance between road mortality indicators in high-income and low- and middle-income countries.

Objective: Compare concordance between road mortality indicators in high-income (HICs) and low- and middle-income countries (LMICs).

Study Design: Ecological study.

Population: The most recent (from 2001 to 2006) one-year road traffic data were extracted from the World Road Statistics report, 2008.

Analyses: Three road mortality indicators: per 100,000 inhabitants (M1), per 10,000 vehicles registered (M2), per 100 million vehicle kilometers traveled (M3) were computed. Concordances between indicators were assessed using scatterplots and intraclass correlation coefficient (ICC).

Results: Out of 192 countries, M1 was available for 125, M2 for 114, and M3 for 60. Despite significant concordances between indicators in HICs (All ICC > or = 0.42, P < or = 0.002), M1 rates were widely dispersed against M3, whereas M2 rates were relatively more dispersed at higher M3. Scatter of indicators in LMICs was inconclusive.

Conclusion: Indicators in LMICs were not concordant possibly due to methodological differences in measuring traffic exposition and underreporting of fatalities.