Epidemiology and outcomes of injuries among trauma patients in Ethiopia: A 5 -years retrospective Analysis

Background: Injury becomes life threatening community health problem associated with significant mortality and morbidity worldwide. Road traffic accident is the most commonly encountered trauma and the leading cause of death and disability from injuries in Ethiopia. The aim of this study is to assess the epidemiology and outcomes of injury in Ethiopian University Hospital. Methods: Institutional based retrospective cross-sectional study was conducted from January 2015 to June 2019. Data was collected using questionnaire adapted from WHO injury surveillance guideline. Bivariate and multivariate logistic regressions were performed to determine factors associated with hospital mortality. Results: A total of 376 trauma cases were included in the study. The majority of 196(52.1%) victims were in the age range of 20-40 years. Road traffic accident was the commonest mechanism of injury 178(47.3%) followed by interpersonal violence 113(30.1%). The majority of patients 135(35.9%) had associated with lower extremity injury and there was 23(6%) mortality in this study. Revised trauma score (RTS) < 10 (AOR=2.5; 95% CI, 1.8-25.6), Glasgow coma scale (GCS) (AOR =0.3; 95% CI, 0.13-0.5), Length of hospitalization (LOS) 1-7 days (AOR=0.1; 95% CI, 0.01-0.8), and Time to arrival >24hr were predictors of mortality in a patient with injury. Conclusion: A lower extremity injury was common and mostly associated with RTA. Length of hospitalization > 7 days, RTS<10, decrease GCS and time to arrival >24hr were factors associated with mortality. Pre-hospital emergency medical service system and trauma registry needs to be established to decrease burden of injury.

mortality and morbidity worldwide 1,2,[11][12][13][14][15][16][17][18][3][4][5][6][7][8][9][10] . According to WHO injury and violence surveillance, more than 5 million people die per year associated with injury which accounts for 9% of world's death 19 . This figure is more than the combined fatalities resulting from HIV/AIDS, malaria and tuberculosis. Approximately, 90% of injury related mortality occurred in low and middle income countries. Road traffic injuries are one of the leading causes of death which accounted for a quarter of 5 million injury death, specifically in 15-29 age categories 19 . It is predicted to be the seventh leading causes of death by 2030 in the world 19 .
In Sub-Saharan Africa, injury related mortality and morbidity is very high specifically in low and middle income countries from which road traffic injury takes the lion share 10,20,21 . Recent Global Burden of Disease (GBD) showed that mortality related with injury in Sub-Saharan Africa is estimated to be 14.6/100000 persons in 2020 as compared to 97/100000 persons worldwide 21 .
In Ethiopia, Epidemiological studies showed that the pattern and outcomes of injury is variable in different regions of the country. A study conducted in University of Gondar revealed that the prevalence of injury was 25% and from which 82% were young males.
The commonest mechanism of injury was Assault (49.9%) and road traffic accidents (48%) 7 . Another multicenter study conducted in Amhara regional state showed that the prevalence of injury in the region was 55.5% 6 . Those who are young and daily laborers, substance abusers and those who are with low monthly incomes were the most likely injury victims 6 . A study conducted in Tikur Anbesa Specialized and teaching Hospital showed that the prevalence of injury was 32.5%. In this cross sectional study, road traffic accident was the most common mechanism of injury (38%) followed by violence (31.5%).
Young population (20-29 years) and those with low monthly income (less than 650 Ethiopian Birr) were more likely to sustain injury incidents when compared to the other population groups 22 . Another study conducted in Yirglem General Hospital reported the prevalence of injury as 49.9% and the most common mechanism of injury was road traffic accident 2 .
In Ethiopia, there is no national prevalence of trauma and national database injury registry for health planners and policy makers who are in need of the national prevalence of injury. Therefore, there it is a need to have the prevalence and outcomes of trauma from different areas of the country for planning and management strategies of injury. The aim of this study is to assess the epidemiology and outcomes of injury in this catchment area.

Study Area
The study was conducted in Dilla University Teaching and Referral Hospital which is found

Data Collection procedures
A structured questionnaire adapted from WHO injury surveillance validated for low and middle-income countries was used to collect the information. We included in the questionnaire the following: socio-demographic data (age, sex, level of education, place of residence, income, living condition, and occupation); injury mechanism; interval time from injury to admission; systolic blood pressure (BP); diastolic blood pressure (DB); pulse rate (PR); respiratory rate (RR); type, mechanism and pattern of injury; revised trauma score; Glasgow Coma Score (GCS) and length of stay (LOS). The outcome was status on discharge.      Road Traffic Accident was the commonest cause death 12(52.2%) followed by assault 8(34%) and the least was found in burn patients. Polytrauma was responsible for the majority of death 10(43.5%) followed by head injury 9(39.1). The mortality of cases with lower trauma score at admission was very high. The mortality of cases that arrived in health institution after one hour was very high, (Table 3). Determinants of patient mortality after injury were considered, with a 95% confidence interval and P < 0.05. Patients with associated abdominal injury, lower extremity injury, time to arrival > 24hrs, being admitted for 1-7 days in hospital, revised trauma score <10, decrease GCS and operation had higher odd of mortality on bivariate analysis Sex, income, age group, type of injury, time to arrival, revised trauma score (RTS), operated on and Glasgow coma scale (GCS) were the variables that had p-value <0.2 and were considered for multiple logistic regression. After adjustment for multiple logistic r e g r e s s i o n , Mortality after injury is three times more likely in a patient with revised trauma score less than ten, (AOR] =2. Being middle income was also another associated factor with less likely to develop hospital mortality than their counterpart. With regard to time to admission, those with time to arrival <1hr and 1-24hr was associated with less likely to have hospital mortality compared with time to arrival >24hr (table 4).

Discussion
The prevalence of injury in this study was 46.6% which is comparable with a study conducted in Yirgalem (49%) 2 . But it was higher than studies conducted University of Gondar (25%) 7 and Tikur Anbesa Hospital (32%) 22 and this discrepancy might be due to poor road safety, more motorcycle transportation in our study area. It was lower than a study conducted in Amhara regional State (55.6%) 6 and Jimma University Referral Hospital 5 and this is explained by study setting and large sources of population compared to this study area. The prevalence of injury in one of Nigerian Tertiary Hospital was lower than half of ours and this might be due to better mode of transportation and road safety 23 .
This study revealed that male gender and young age groups, 20-40 age groups, were the most commonly injured ones who are supposed to be the gear changers of the economic activities of the country. This finding is consistent with findings of WHO injury and violence surveillance facts and other studies conducted in Sub-Saharan African countries 10,[19][20][21] . The majority of patients were primary School attendants and student in regard to occupational status. This finding is comparable with a study conducted in Yirgalem, Nigeria and Tanzania 2,23,24 . A multicenter study conducted in Amhara regional state found that illiterate and Farmer were the most likely injured patients in contrary to this study finding 6 .
In this study, patients from rural area are more affected with injury as compared to urban and this finding is consistent with a study done in University of Gondar and Yirgalem 2,7 .
However, patients residing in Urban are affected more likely as compared to patients from rural in multicenter study conducted in Amhara regional state and Sub-Saharan African countries 6,20 . This discrepancy might be due involvement of multicenter from big towns in the region.
Road traffic accident was the commonest types of injury (47.3%) followed by interpersonnel violence (30.1%) which is comparable with findings of Sub-Saharan African countries and WHO reports 1,20,21,25,26 . In this study, lower extremity injury is the most common types of injury unlike other studies conducted in Africa which was head injury [5][6][7][8]22,27,28 . This discrepancy might be due to Head injury case referral as our hospital didn't have neurosurgical facilities.
The study showed that the prevalence of death was high (6%) as compared to a study conducted in University of Gondar (2.11%) and the difference might be explained by study setting, referral linkage and admission.
This study showed that patients who arrived in greater than twenty four hours after injury are more likely to die as compared to patients arrived in less than twenty four hours. This finding is consistent with a study conducted in Tanzania 24 and Ruanda 8 . This study revealed that duration of Hospitalization greater than seven days was an independent predictor of hospital mortality as compared to patients hospitalized for less than seven days. This finding is in line with a study done in Tanzania 24 . This study showed that Revised Trauma Score and Glasgow Coma scale was significantly associated with patient mortality. The patient mortality increases three times in reduction of Glasgow Coma scale by one unit whereas patient mortality was three times more likely in patients with revised trauma score less than ten

Limitations
This study has a number of limitations despite its significant contribution as a source of information for prevention and management strategies. As this is a cross-sectional hospital based study, the findings are not generalizable to the general population.
Besides, lack of trauma registry and incomplete patient charts were the major challenges.

Conclusions
The prevalence of injury in this study is very high and took the lives of the most productive age groups of the population. Road traffic injury and violence are the two most common causes of injury which counted for more than eighty-percent of deaths (20/23).
Patients with low trauma score and came late are more likely to have significant mortality and morbidity. In this study, there were more deaths associated with head injury and Polytrauma. There is a need to have urgent injury preventive and management strategies along with establishment of Pre-hospital Emergency Medical service System.

Funding
No funding was obtained from any organization Authors' contributions SA and BJ conceived the idea design the project. SA, BJ, HM and BB involved in data collection, interpretation, analysis and manuscript preparation Figure 1 flow diagram of sampling procedure