Chronic pain prevalence two years after a road crash and its biopsychosocial risk factors-Results from the ESPARR cohort*

Context: Twenty to 50 million people suffer non-fatal road crashes in the world each year, representing a trauma that is particularly likely to result in chronic pain. This condition is very common, affecting about 10 to 30% of Europeans in a lasting and costly way. A better understanding of the problem and the identification of risk factors could allow to develop preventive measures. Aims and method: This observational registry-based cohort study aims to measure the rate of and evaluate the risk factors for road crash-related chronic pain (RCRCP) 2 years after the crash. Road crash victims from the ESPARR cohort of all ages who visited hospitals in the French department of Rho<SIC>ne and respondent to 2-year follow-up were included (n=1071). Results: Two years after the crash 45% of victims reported RCRCP. This rate varies according to age, from 16.5% under 16 years old to 51% for adult victims, according to type of road-user, from 38.3% for bicycles to 54% for motorised-two-wheeler vehicles and according to severity, from 43% for lightly or moderately injured patients to 77% for seriously injured patients. RCRCP at two years was significantly associated with various biopsychosocial factors: being under 16 years as a protective factor (OR=0.37, p<0.0001); level of lesion severity (OR=1.17, p<0.0001 for one more unit of MAIS), a limb injury (OR=1.32, p=0.0001), having a history of osteoarticular disorders (OR=1.16, p=0.03) and having experienced a negative life event in the past year (OR=1.13, p=0.04) increased the risk of RCRCP. Conclusion: Our study shows that nearly half of road crash victims experience RCRCP two years after the crash. The methodology allowed us to highlight variables that have been poorly or not at all studied in the literature, such as being under 16 years old or having experienced a negative life event during the past year.