The present study is a part of the Persian Traffic Cohort (PTC) study, and cases were selected from the Iranian Integrated Road Traffic Injury Registry (IRTIR) system used in it. The Ministry of Health and Medical Education designed IRTIR with the collaboration of WHO. The comprehensive IRTIR system has been established in Emam Reza and Shohada hospitals as the two referral specialty centers in the Eastern Azarbaijan Province, Iran. The IRTIR gathers data at several sections as follows: crash scene section, emergency section, hospital admission section, forensic medicine section, and post-discharge section.
We recruited 190 injured motorcyclists admitted to the two referral specialty hospitals of Emam Reza and Shohada in Tabriz from June 2018 to January 2019 willing to participate in this study were enrolled. Among them, we could contact 171 injured people three months after the accident. The inclusion criteria were as follows:
1) Being involved in traffic injury (according to the United Nations Economic Commission for Europe (UNECE) definition (20), "road traffic accidents are those accidents:
a) Which occurred or originated on a way or street open to public traffic
b) Which resulted in one or more persons being killed or injured
c) In which at least one moving vehicle was involved."
2) Being a rider or pillion passenger of motorcycle involved in traffic crash accordance with V20-V29 and V31 from International Classification of Diseases-10th revision (ICD-10)
3) Having registered integrated road traffic injuries (hospitalization in trauma centres)
4) Having the participant's consent for inclusion in the study
5) Being lucid, conscious and cooperative during the telephone follow up
Those injured individuals who either were in a coma during the phone follow up or could not talk due to severe pain were excluded.
2.1. Data collection
For each injured motorcyclist (both the rider and the passenger 'if applicable') admitted to the hospitals (Emam Reza and Shohada), baseline measurement was collected through a face-to-face interview at the hospital admission section of IRTIR through data collection tool in the nursing station.
The following information was gathered using a face-to-face interview at the hospitals:
1) Demographic characteristics (the name of the hospital where they had been admitted, admission date, case number, national ID number, age, sex, nationality, level of education, marital status, job, address, landline number, cellphone number, cellphone number of next of kin or anyone who could be contacted after the admitted individual was released from the hospital).
2) Crash related variables including:
- a) Information regarding the time and location of the accident (such as the day, month, and year of the accident, the exact day of the week, the time of the accident, whether light status (daytime, nighttime), the weather condition, road condition at the time of the accident and whether it was slippery, whether the accident occurred in the city or in the suburbs).
- b) Information regarding the vehicle (including the number of vehicles involved in the accident, the type of vehicle involved in the accident and the mechanism of accident (e.g., vehicle-fixed object crash, vehicle-vehicle, overturning, vehicle-pedestrian, and vehicle-animal crash)
- c) Information about the person (including the role of the injured person: whether s/he was the cyclist or the passenger, whether the injured rider had a rider license, whether s/he had the experience of riding a motorcycle, the average time of riding a motorcycle per day, the average number of days the injured motorcyclist rides the motor per week, whether a cellphone was used during riding and if yes whether they were using headphones or they were holding their cellphone in their hand, the motorcyclist communication status with the passenger before the accident, whether the motorcyclists had drunk alcohol and/or had taken drugs). All of these data were recorded in the comprehensive IRTIR system.
3) Information regarding the severity of accident injuries was extracted from the Health Information System (HIS) of the hospitals. The type of injuries was defined according to ICD-10 codes as follows: head injuries (S00-S09), neck injuries (S10-S19), thoracic injuries (S20-S29), injuries to the abdomen, lower back, lumbar spine and pelvis (S30-S39), shoulder and above elbow injuries (S40-S49), elbow and forearm injuries (S50-S59), wrist and hand injuries (S60-S69), leg and pelvis injuries (S70-S79), knee and lower knee injuries (S80-S89), foot and ankle injuries (S90-S99).
- Follow up assessment including QOL
One and three months after the accidents, injured hospitalized motorcyclists were contacted by telephone for a follow-up. Required information for performing the follow-up was collected from the IRTIR system. The call duration for each person lasted from 5 to 10 minutes.
The EQ-5D-3L questionnaire was developed in 1987 by a team of researchers from five European countries to assess the QOL. This standard questionnaire covers five aspects of mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. For each of these aspects, the following scale is considered: 1) I have no problem, 2) I have some difficulty, and 3) I have many issues. The overall score is calculated as the sum of the scores obtained from each aspect divided by 5. The average overall score is between 1 (high QOL) and 3 (low QOL) (21). A higher score shows a bad QOL.
The Iranian socio-economic assessment questionnaire (second brief version) covers six items, including occupation, income per month, years of successful education, private housing, private car, and the share of health expenditure to the total expenditures. To measure the overall score, questions four, five, and six are multiplied by 0.33; then, the sum of the answers to all questions is calculated. To classify the economic-social status to very low, low, medium, and high levels, statistical quartiles of the overall score are used. The validity and reliability of this questionnaire were proved by Dr. Sadeghi et al. (22).
2.3. Statistical analyses
Descriptive statistics for normal quantitative, not normal quantitative and qualitative variables have been reported as mean (standard deviation), median (P25-P75), and frequency (percent), respectively. We checked the normality of continuous variables (including age, number of riding days during last week, time of accident occurrence, hospital admission days, and quality of life score) by the Shapiro-Wilk test. Demographic variables, baseline variables, and quality of life score were compared in the first and second follow-ups using the Chi-square test, Mann Whitney, and independent t-tests.
In the present study, our data was longitudinal and the Generalized Estimating Equations GEE model is recommended more for longitudinal data that could manage the correlation between multiple measurement (23). So, Bivariable and multivariable linear models of the GEE with unstructured variance-covariance matrix were used to determine the factors affecting the QOL of injured motorcyclists. In this model, the QOL score was the dependent variable, and the baseline variables were considered as independent variables. In the bivariable model, we entered all demographic variables (included age, sex, level of education, marital status, and job) and baseline variables to the model. Therefore, we tested the association of these variables with the QOL score. In the multivariable GEE model, the variables that with a p-value <0.1 (24) in the bivariable were included in the model. The backward elimination, using Wald test, was used to reduce the model. In all analyses, a p-value<0.05 was considered statistically significant. Stata SE software (Version 13) was used for data analysis.
This study has been approved by the Ethics Committee of Kerman University of Medical Sciences (Ethics code: IR.KMU.REC.1397.141) and carried out under the national ethical codes for the primary cohort and registry. Also, verbal consent was received from all participants before enrollment.