Incidence of road injuries in Uruguay


[Download detailed results tables: Uruguay-WebTables]
Last Updated: Sept 27 2009

Important: Please note that the results presented here are preliminary. Additional adjustments will be necessary as the results are made consistent with the ongoing Global Burden of Disease (GBD-2005) project, for which the results presented here are an input. Final estimates of the GBD-2005 study will be released in late 2010.  

About this report

Reliable statistics of road injuries are an essential input for describing the public health burden of injuries, evaluating the impact of safety policies, and benchmarking achievements. While injury surveillance systems are common in high income countries, most low and middle income countries are unlikely to have such capacity for several decades. In the interim, estimates should be derived by harmonizing injury statistics from the wide array of data sources that may be available in a country or region. 

This report summarizes our findings for the incidence of deaths and non-fatal injuries from road crashes in Uruguay. It is one of a series of national road injury assessments that we are producing during the course of this project. The intended audience of these reports includes the global donor community, the international research community, and national health and transport policy makers. We are committed to keeping this project open-source and collaborative in nature. All readers are encouraged to provide feedback to help improve methods, incorporate other sources of information, and suggest more effective methods for communicating these results.


Summary Results
In 2004, road crashes resulted in 457 deaths in Uruguay representing an annual injury rate of 13.8 deaths per 100,000 people. In addition, over 43,000 people were victims of non-fatal injuries due to road crashes. While the road injury death rate in Uruguay is typical of other countries in the Latin American region (Figure 1), it is 2.4 times the death rate in countries with the best road safety performance (Sweden, UK, and Netherlands). 

Injuries as a whole, including from unintentional and intentional causes, resulted in 1900 deaths or 6% of all deaths in Uruguay in 2004. When compared with deaths from other diseases, this estimate puts injuries at the third leading cause of death in Uruguay. 

Road injuries are the second leading cause of injury deaths in Uruguay, second only to suicides and substantially in excess of deaths from homicides (Table 1). In 2004, road injuries account for nearly one-fourth of all injury deaths in Uruguay. 

How did we compute these estimates?

Our general methodology for estimating deaths and non-fatal injuries involves piecing together data from a wide array of sources that typically include death registers, hospital records, funeral records, health surveys, and police reports. This requires filling information gaps, mapping from varying case definitions, deriving population based incidence estimates from sources that may not track denominator populations, and appropriately reapportioning cases assigned to poorly specified causes. For a general description of the broad methodology, please visit the Methods-overview section of our website.

The following sections describe the specific data sources used, the estimation methods, and the key results for our estimates of road injuries Uruguay. The analytical adjustments to the data introduce uncertainty in the estimates. Thus, wherever possible, we have outlined the effects of the adjustments on the estimates. 

Overview of data sources

We estimated the incidence and distribution of road injury deaths in Uruguay using national death registration data obtained from the WHO Mortality Database. We estimated the incidence and distribution of non-fatal injury deaths using the results of the 2002/2003 World Health Surveys.

Estimates of road injury deaths

Our review of data sources for estimating national road injury deaths in Uruguay revealed two potential data systems: national death registration data and police reports. In this study, we have computed estimates of national road injury deaths from the former (death registration) and compared them with those reported by the police. We obtained death registration data from the publicly available WHO Mortality Database. These data are tabulations of deaths recorded by national civil registration systems. Typically these systems record age, sex, and causes of death coded using principles of the International Statistical Classification of Diseases (ICD). 

A total of 43 years of data were available, most recently for the year 2004. We only analyzed data for the most recent six years available (1997, 1998, 1999, 2000, 2001, and 2004), which had causes of death coded to ICD-10 categories. Data from prior years was not analyzed because it is not reported at a level of detail that allows us to use our analytical estimation methods. In particular, 15 years of data from the ICD-9 coding era has not been analyzed because the data was reported in the WHO Mortality Database using a condensed tabulation list (ICD-9 BTL). 

Reclassification to GBD-2005 definitions: We reclassified age into 38 age-sex groups. The age definitions match those used by the GBD-2005 project and are available on the GBD-Injury expert group website. Click here to go directly to the age definitions. 

We reclassified the ICD coded deaths to the definitions of road injuries (and other injuries) as recommended by the GBD-Injury expert group [Click here for full details]. These definitions map all ICD codes for external causes of injury to 48 fully-specified cause categories and 21 partially-specified and undetermined cause categories. The fully-specified cause categories include nine road-user categories:
  • Pedestrian (V01-V04, V06, V09), 
  • Bicyclist (V10-V19), 
  • Two-wheeler rider (V20-V29), 
  • Three-wheeler occupant (V30-V39), 
  • Car occupant (V40-V49), 
  • Van occupant (V50-V59), 
  • Truck occupant (V60-V69), 
  • Bus occupant (V70-V79), and,
  • Other road injury (V80, V82, V83, V84, V85). 
In addition, there are two partially-specified sub-categories of road injuries:
  • Road injury - unspecified occupant, i.e. not pedestrian or bicyclist (V87-V88), and,
  • Road injury - unspecified road user (V89, Y85.0)
Table 2 shows the distribution of the 1900 injury deaths reported in the death registration data for the year 2004. It should be noted that the 21 partially-specified categories have a hierarchical structure of specificity and many of these categories are not related with road injuries. 

We assessed the quality of the death registration data based on the distribution of the number of deaths in the partially specified categories. As shown in Table 2, almost all (94.3%) of the deaths that are specified as being from road injuries do not have a road-user specified. Because road-user is known for only a small fraction of road injury cases, disaggregation of deaths by type of road-user based on death registration data will likely lead to biased estimates. Over one-quarter (27.4%) of the injury deaths specified as being from unintentional injuries do not have an injury mechanism specified. While this is not unusual for a death registration system (our analysis of global data has found that this category can exceed 20% in many countries), it is nevertheless a large number that can lead to biases in the estimates.  

Reallocation of injury deaths coded to partially-specified causes: The deaths classified to partially-specified and undetermined cause categories were redistributed over the fully-specified categories. All redistributions were done in proportion to the number of cases in the fully-specified causes within age-sex groups. The redistribution is done in 21 steps, one for each partially-specified category. This respects the information content in the hierarchical structure of the partially-specified categories. Thus, several of these steps do not affect the road injury estimates.  For instance, the category of firearm: undetermined intent was  redistributed over the categories for firearm: unintentional, firearm: self-inflicted, and firearm: inter-personal. This redistribution step has no effect on the road injury estimates. Only the redistribution of the following partially-specified categories has an effect on road injury estimates:
  • Road injury - unspecified occupant, i.e. not pedestrian or bicyclist, 
  • Road injury - unspecified road user,
  • Unspecified transport injury,
  • Unspecified unintentional injury,
  • Unspecified mechanism - undetermined intent,
  • Unspecified mechanism - unspecified intent,
The effect of these redistribution steps is evident from Figure 2. The death registration data has 353 deaths specified as road injuries. As expected from the distribution of deaths shown in Table 2, the only substantial increase in the estimates of road injury deaths occurs when deaths coded to unintentional injuries- unspecified mechanism are reallocated. This results in an increase of 100 deaths. 

Adjustments that have not applied yet: Two key adjustments that are likely to modify the road injury death counts have not been applied yet. First, we have not reallocated deaths coded to unspecified causes outside the ICD injury chapter. This reallocation has not been done yet because research into the causes of deaths coded to this category is currently ongoing. However, it should be noted that in Uruguay, only a relatively small fraction (7.4%) of deaths are coded to this category and the effect on road injury death counts is thus expected to be small. 

Second, we have made no adjustments to account for incomplete death registration because estimates of completeness of global death registration data are currently being developed. However, our preliminary comparison of total all-cause deaths reported in the death registration data analyzed by us with deaths reported by the UN Population Division suggests that death registration in Uruguay is near complete. It should be noted that both of these adjustments would increase the estimated death counts. Thus, the mortality results presented here likely underestimate the true number of road injury deaths.

Comparison of our estimates with other sources

Our estimate of road injury deaths in Uruguay are similar to those reported in the 2009 WHO Global Status Report on Road Safety, which are based on police reports (Figure 3). 









Road deaths by age and sex

Most road deaths occur among adult males (Figure 4a). Over 3/4th (76%) of all road injury deaths were men and most of these men (88%) were adults older than 20 years. Death rates (Figure 4b) among men are over three times higher than those among women overall. Men have higher death rates for all age groups but the gender differential is smaller among the elderly.  Both death counts and death rates rise dramatically in the transition in age from childhood to young adults (see age groups 10-14 years and 15-19 years). Death rates continue to rise with age and are highest among the elderly. 

Such age and sex patterns in deaths and death rates are consistent with those seen in other countries. For the most part, the gender differentials in death rate are a result of higher exposure to road traffic among men in combination with higher risk-taking behavior. Similarly, the age pattern of death rates partly reflects patterns of exposure and partly case-fatality rates. While exposure to road traffic declines with age among older populations, the bio-mechanical tolerance to injury (i.e. the likelihood of death in the event of a crash) also declines, resulting in increasing death rates with age. 


Estimates of non-fatal road injuries

The incidence of non-fatal road injuries can be estimated from various sources, including police reports, hospital administrative records, and population surveys. Among these, police reports are widely known to underreport road injury cases in low income countries as well as in high income countries. Hospital records have the advantage of providing detailed medical descriptions of injuries making classification of injuries by severity possible. However, estimation of population rates is difficult without investing substantial efforts in identifying the hospital catchment population. Thus, population based health and injury surveys are the most reliable sources of information for incidence of road injuries, especially in information-poor settings.

We estimated the incidence of non-fatal road injuries in Uruguay using the 2002-2003 World Health Surveys (WHS), a nationally represented household survey that included questions on road injury involvement. These surveys, which were conducted by the World Health Organization, provide a unique opportunity for cross-country comparisons of non-fatal injuries because they asked the same set of questions in 53 countries, most of which are low- or middle- income countries. The surveys included the following set of road injury related questions in their household module:
  • In the past 12 months, have you been involved in a road traffic accident where you suffered from bodily injury? 
    • Yes/No
  • When (in the last 12 months) did the accident happen? 
    • Within the last 30 days/ 1-2 months ago/ 3-5 months ago/6-12 months ago/ Do not know
  • Did you receive any medical care or treatment for your injuries? 
    • Yes/No
  • Where did you first receive care? 
    • On-site, ambulance/Hospital/Outpatient facility/Private physician/ Traditional healer/ Other
  • Was it government operated or private? 
    • Government operated/ Private
  • How soon after the traffic accident occurred did you first receive care? 
    • In one hour or less/ In over one hour but within 24 hours/More than 24 hours later
In Uruguay, 2976 interviews were conducted as part of the WHS, with a response rate of 100% and only 0.6% of the surveys had missing responses for the question on bodily injury in road accidents. In our analysis of the WHS, we replaced the missing values for this question with the predicted value from a logistic regression model fit to the cases with a non-missing response. The model used the response to this question as the dependent variable and the following independent variables: gender, age groups, place of residence, permanent income quintile, country, marital status, education, occupation, self-rated health, visual acuity (seeing and recognizing a person from across road), and alcohol consumption as predictor dummy variables. We used survey (svy) commands in Stata 10 for the analysis of the WHS.

Non-fatal injuries by age, sex, and residence

Our analysis of the 2002/2003 WHS suggests that over 43,000 people in Uruguay are involved in non-fatal road crashes annually. This corresponds to 1.3% [95% CI:1.0 -1.6%] of the population. 

Although road injury incidence is slightly higher among residents of rural areas than residents of urban areas, the difference is not statistically significantly (Figure 5). Similarly, while men have higher rates of non-fatal road injury incidence than women, the difference is not statistically significant (Figure 6).  Road injury incidence is higher among young adults (18-44 years) than among elderly, but the differences are not statistically significant (Figure 7). It should be noted that while the non-fatal injury rate among those older than 65 years is the lowest of the three age groups, the death rate among the elderly (Figure 4b)  is the highest, pointing to high case fatality rates among the elderly. 
                    

Acknowledgements

These country reports were produced as part of a project funded by the World Bank Global Road Safety Facility. The results presented here are based on secondary data analysis of data collected by various national and international agencies.
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Kavi Bhalla,
Oct 4, 2009, 9:23 PM