Injury
Drink-driving motor crashes and alcohol-related diseases
drink-drivers. Brewer et al. found that drivers between the age of
21 and 34 years who died in an alcohol-related crash were 4.3
times more likely to have been arrested previously for driving
while intoxicated compared with drivers who died in non-alcohol
related crashes.9 For drivers 35 years or older, those killed in an
alcohol-related crash were 11.7 times more likely to have had a
previous arrest for drink-driving than drivers killed in non-alco-
hol-related crashes. While Brewer et al.’s research shows that re-
peat drink-drivers are at higher risk of dying in an alcohol-related
crash, there has been a dearth of literature on whether drink-driv-
ing offenders actually have an alcohol dependency problem.
Few studies have investigated the relationship between alco-
hol-related medical conditions (defined as one or more of the
diagnoses listed in Table 2) and road crashes. A study of Western
Australian drivers investigated alcohol-related medical conditions
as a risk factor for future alcohol-related motor vehicle crashes.10
Results indicated that only 3% of patients admitted to hospital
for an alcohol-related condition would be involved in a future
alcohol-related motor vehicle crash. A limitation of that study,
however, is people with alcohol dependency are unlikely to re-
quire hospitalisation for an alcohol-related medical condition until
later in their ‘alcohol career’. Consequently, an alcohol-related
motor vehicle crash is likely to occur before, rather than after,
hospitalisation for such conditions.
external cause of injury by ethanol or methanol poisoning, and
external cause of injury by alcohol aspiration.
It was necessary to link those drivers or riders identified in our
cohort to their hospital records. This was achieved by accessing
the Health Services Linked Database.All hospital admissions and
death records for each cohort member admitted to hospital for an
alcohol-related medical condition between 1 January 1988 and 31
December 1992 (the cohort recruitment period) and 31 December
2000 were extracted from the database. This ensured there was a
follow-up period of between 8 and 13 years from the date of
hospitalisation following a police-reported motor vehicle crash.
Details (including name, gender and date of birth) of individuals
involved in a crash were linked using probabilistic techniques to
the hospital data. The specific techniques used for linking (or
matching) the records are outlined in the paper by Rosman.11 It is
important to note that each individual presenting to a hospital in
WesternAustralia is allocated a unique identifier, which minimises
the likelihood of counting an individual twice.Therefore, all drivers
or riders in the cohort were followed-up using their unique
identifier.
The survival time for this study was calculated from the date of
hospitalisation following a police-reported motor vehicle crash
through to the date of first alcohol admission (as outlined above),
loss to follow-up, or censoring.
The aim of this study is to investigate the association between
involvement in an alcohol-related motor vehicle crash requiring
hospitalisation and subsequent admission to hospital for alcohol-
related medical conditions.
A description of the demographic characteristics of the cohort
was undertaken using SPSS software. Comparison of the means
for continuous variables was undertaken using independent t-tests.
Tests of association were undertaken using the chi-square test with
continuity correction where appropriate. Survival times (alcohol
versus non alcohol-related motor vehicle crash) were calculated
and the significance of any difference was determined by the log-
rank test. To determine the factors associated with alcohol-
related hospital admission (including time to first alcohol-related
hospital admission), both logistic regression and Cox’s propor-
tional hazards analyses were undertaken. Factors included in the
models were gender, age, Indigenous status and whether the driver
was involved in an alcohol-related motor vehicle crash. All
p-values were two-sided and were considered significant at 0.05
and 95% confidence intervals were calculated using the standard
errors from the analysis.
Methods
A population-based prospective cohort study was undertaken
involving all drivers or riders of motor vehicles who were
hospitalised in Western Australia during the period 1988 to 1992.
Motor vehicle crashes were identified through the Western
Australian Road Injury Database, which links police crash reports
obtained from the Traffic Accident System of the Main Roads
Department of Western Australia with hospital discharge records
for the State ofWesternAustralia.To determine whether the driver
involved in a motor vehicle crash had a BAC exceeding 0.05gm/
100ml only police-attended motor vehicle crashes were included
in the cohort (n=3,286). A BAC exceeding 0.05gm/100ml was
defined using a calibrated breath test by a police officer. This
equipment is used to provide evidence in court.
Results
There were 3,286 drivers or riders of a motor vehicle admitted to
hospital following a police-attended motor vehicle crash between
1988 and 1992 in Western Australia. The number of observations
was equally distributed across the five-year recruitment period,
namely 20% per year (χ2=4.27, df=4, p=0.371). Seven per cent
(n=217) of the cohort was classified as an alcohol-related (had a
BAC ≥0.05 as reported by the attending police officer) motor vehi-
cle crash.The average age of the cohort was 32 years (range=15-88
years) with significantly more males (71%, n=2,345, χ2=7.94, df=1,
p=0.005). Three per cent (n=95) of the cohort were Indigenous
Australians. Descriptive statistics for alcohol and
The outcome of interest was a subsequent alcohol-related
hospital admission. An alcohol-related hospital admission was
defined as a medical diagnosis that could only have resulted from
excessive alcohol consumption. These medical diagnoses were
defined as having an aetiologic fraction of 1.0 (100% attribution)5
and were identified using the ICD-9-CM (prior to 1 July 1999)
and ICD-10-AM (from 1 July 1999 onwards) codes as alcohol
psychosis, alcohol dependence, alcohol abuse, alcohol
polyneuropathy, alcohol cardiomyopathy, alcoholic gastritis,
alcoholic liver cirrhosis, ethanol toxicity, methanol toxicity,
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