Patient and injury characteristics associated with road traffic mortality in general hospitals in southern Thailand

Data on traffic injuries were obtained from IS database between 2008 and 2013, from the Office of Disease Prevention and Control (ODPC). These data are hospital-based data collected from general hospitals of 5 provinces in upper southern Thailand. Data were collected by using an IS form. Patient and injury characteristics were obtained by interviewing patients or bystanders, performed by nurses. Information on demographic factors of patients including age and gender, and injury characteristics including road user type, type of vehicle, safety device use, pattern of crash, mechanism of injury, body region of injury, and survival status after receiving treatment were extracted from the database. Patients could have died at any stages before, during or after treatment in the ED or the inpatient department (IPD). There were 78,862 cases of traffic injuries included in this study. Data were cleaned to eliminate the errors of coding and recording before performing data analyses. Age group was classified as below 15, 15–24, 25–44, and 45 years and older. Road user type was grouped as drivers, passengers, pedestrians, and unknown. Type of vehicle was categorized as motorcycle, motor car, pedestrian, others, and unknown. Fastening seat belt or helmet was grouped as yes, no, and unknown. Pattern of road traffic crash was categorized as crashed with or by a motorcycle, crashed with or by motor car, crashed with or by others, and unknown. Mechanism of injuries was grouped as blunt, penetrating, or blunt with penetrating, and unknown. Body region of injuries was categorized as head or neck, facial, chest, abdominal or pelvic cavity, extremities or pelvic girdles, external injuries, and unknown.

Descriptive statistics were calculated for each variable. In this study, the determinants consist of patient demographic factors and injury characteristics. The outcome is road traffic mortality. Chi-squared test was used to find the association between determinants and outcome. Logistic regression analysis was performed to identify the strength of association between determinants and outcome. P-value of <0.05 was used to define statistical significance. Adjusted odds ratios (aORs) together with their 95% confidence intervals (95% CIs) were used to describe the independent association between predictors and outcome. R program was used for data management and statistical analysis [24].

Road traffic injuries were equally distributed by year, except for the year 2008 with the lowest percentage (9.1%). The majority of injuries occurred in males (61.7%). Patients aged 25–44 years had the highest percentage of road traffic injuries (35.8%) followed by age groups 15–24 years (30.2%), and 45 years or older (19.2%), respectively. The majority of road user types were drivers (68.6%) and motorcyclists (78.4%). There were 61.0% of injury cases who did not wear a helmet. The major pattern of road traffic crash was crashing with or by motor car, accounting for 24.2%, followed by crashed with or by motorcycle for 21.7%. The typical mechanism of injuries was blunt, accounting for 88.8%. About 45.7% of injuries by body region were external injuries. There were 1.8% of patients who died from traffic injuries as summarized in Table 1.

Table 2 summarizes the associations between road traffic mortality and independent variables based on chi-squared test. To eliminate the collinearity between the variables, type of road users, type of vehicle, and safety device use were combined to create a new variable called road user–vehicle type–safety device use. The results showed that three-fourths of road traffic deaths occurred in males (75.3%). The predominance of deaths occurred in the age group from 25 to 44 years, accounting for 44%. About 37.6% of deaths were drivers or passengers using motorcycle and not wearing helmet, whereas 9.9% of deaths were drivers or passengers using motor car and not fastening the seat belt. Most of the deaths were by crash by motor car, accounting for 42.4%. The major mechanism of injury among the death cases was blunt (82.2%). There were 45.8% of deaths from head or neck injuries. Results from chi-squared test show that gender, age group, road user–vehicle type–safety device use, pattern of traffic crash, mechanism of injuries, and body region of injuries were significantly associated with road traffic mortality (P < 0.001) as summarized in Table 2.

Table 3 summarizes the association between demographic factors and injury characteristics with road traffic mortality from multivariate analysis. The results showed that gender, age group, road user–vehicle type–safety device use, pattern of road traffic crash, mechanism of injuries, and body region of injuries were statistically significantly associated with road traffic mortality. Males were more likely to die from road traffic injury than females by 1.66 times. Road traffic mortality significantly increased with age. Patients aged 15–24, 25–44, and 45 years and older were more likely to die by 1.95, 2.83, and 2.82 times than patients aged less than 15 years. Driver or passenger using motorcycle and not wearing helmet, driver or passenger using motor car not fastening seat belt and pedestrian had higher morality than driver or passenger using motorcycle and wearing a helmet by 2.08, 3.37, and 5.65 times, respectively. Those with penetrating or blunt and penetrating injuries were more likely to die by 1.55 times than those with only blunt injuries. Those who crashed or were crashed by motor car had higher mortality than those who crashed or were crashed by motorcycle by 2.02 times. Having head or neck, chest and abdominal or pelvic cavity injuries induced higher mortality than injuries to extremities or pelvic girdles by 6.96, 4.21, and 4.16 times, respectively, as summarized in Table 3.

This current study assessed the road traffic mortality and its determinants from general hospitals in southern Thailand. Road traffic accident mortality in general hospital records was found to be 1.8% of all injuries. Gender, age group, road user– vehicle type–safety device use, pattern of road traffic crash, mechanism of injuries and body region of injuries were significantly associated with road traffic mortality.

Our study data had fairly low rate of road traffic mortality when compared to other countries, such as 2.2% from trauma referral in hospitals of Tanzania [25], 4.9% from trauma center care hospital in Libya [26], and 7.7% from a teaching hospital in Kenya [6]. This low rate of mortality might be because the severe cases from traffic accidents who were admitted to general hospitals tended to be referred to tertiary hospitals, due to the lack of advanced medical equipment, treatment, and specialists.

In this study, about three-fourths of road traffic mortalities were males. Similar results were found in studies conducted in Ghana by Der et al. [27] and in Vietnam by Ngo et al. [21].

Moreover, this finding is in agreement with the results of several studies [28, 29]. This might be due to more frequent driving, having driving risk behaviors, and more exposure to driving occupations. The risk of road traffic mortality increased with age. The result matches the findings from several studies [30, 31, 32, 33, 34]. This result may be explained by the deterioration in health with aging. Even minor injuries can bring serious health problems, require long time of recovery, and increase the risk of death for elderly persons [33, 34].

Pedestrians had elevated risk of mortality. Our finding is consistent with the findings of several prior studies [35, 36, 37, 38]. The possible reasons for higher mortality among pedestrians might be more severe impacts, such as pedestrians crashed from back, crashed at high speed or by drink driver, and crashed directly by the vehicle without any protection. Not wearing a helmet or fastening a seat belt gave higher risk of mortality. This finding supports many other studies [1, 4, 7, 39]. Wearing helmet or fastening seat belt can protect against injuries and mortality from accident efficiently. It has been shown that the use of safety helmets and fastening seat belts is a most effective way to reduce mortality and morbidity from traffic injuries [1]. It seems possible that either further education about the benefits of fastening seat belt or helmet use for drivers and passengers or seat belt or helmet laws applied to more drivers or passenger might increase these safe behaviors. In Thailand, helmet was used by more than 25% of motorcycle drivers between 2005 and 2009 [11], but in this current study only in southern Thailand in 2008–2013 it is shown that the helmet use was less frequent (13.3%). Government should rigorously enforce laws on using injury-protective devices.

Mortality when crashed with or crashed by motor car was significantly higher than crashed with or crashed by motorcycle. This is supported by studies conducted in Iran, USA, and Albania [28, 40, 41]. The probability of mortality in the event of a crash with motor car is elevated, but the main road users in this study were motorcycle users. Driving at a high speed is common among car drivers, and this also increases the chances of getting in an accident. Accidents from high-speed driving, drowsiness, fatigue, and driver health status result in severe injuries and mortality [42, 43].

Mortality from penetrating or blunt and penetrating was higher than from blunt trauma only. This is because penetrating injuries can be seen from external bleeding, while blunt injuries cannot be evaluated for bleeding from external appearance. The mechanism of blunt and penetrating affects both internal and external organs, thereby tending to have higher severity of injury. Our current study contrasts with other studies that have reported blunt injuries only as the majority in mortality cases, in Iran, USA, and Egypt [13, 44, 45].

Head or neck injuries had higher mortality than injuries to extremities or pelvic girdles. High mortality from head injuries was reported in previous studies, such as in Kenya, Laos, Vietnam, Libya, and China [6, 19, 21, 26, 46]. This might be due to most drivers and passengers not wearing helmets, despite their use being required by law. In addition, this current study revealed that chest and abdomen or pelvic cavity injuries also had high mortality, because the single vital organ injuries of patients are too serious to be recovered.

There are some limitations to this current study. Some information of patients was not recorded, and there were missing data in almost all the variables. However, the largest percentage of missing data was in the unknown status of fastening seat belt or using helmet. The data used in this study were secondary data and might contain some errors that cannot be detected. Some information related to treatment and the status of patients after discharging from the hospital was not recorded.

Any policies and measures set up by the authorities to reduce mortality from road traffic injuries should emphasize males, older aged people, pedestrians, not wearing helmet or fastening seat belt, being crashed with or by motor car, having blunt and penetrated as the mechanism of injury, and having head or neck, chest, or abdominal or pelvic cavity injuries.