Neck Injury after Whiplash Trauma in a Defined Population in Northern Sweden – Long-Term Sick Leave and Costs of Low Productivity

Background: Neck injuries following whiplash trauma can lead to long-term sequelae. Population-based studies covering traffic and non-traffic whiplash trauma are rare. The aim was to describe the incidence of neck injuries following whiplash trauma during one year, from a well-defined area served by a single hospital, and the resulting long-term sick leave during a five-year follow-up. Possible risk factors for sick leave and the cost of lost productivity were also studied. Methods: From the injury register of Umeå University Hospital, the year 2001’s data set of soft tissue neck injuries and fractures was extracted. Those injured by whiplash trauma were included. The Swedish Social Insurance Agency provided five-year post-injury data on sick leave in 2006. Epidemiological aspects were described, a logistic regression was conducted to find risk factors for long-term sick leave, and the cost of lost productivity was calculated. Results: Five hundred and twenty five cases were included. The incidence was 383 per 100,000 person-year. In 14% of 18-64 year olds, sick leave was granted for more than two weeks and the median number of sick days in this group was 298. Old age, having a Whiplash Associated Disorders (WAD) grade of 1, being injured in traffic and being injured at velocity exceeding 50 km/h were significant risk factors for sick leave. A few (6%) had fractures, however, their average sick-leave time was not significantly longer than the sick leave of those with only soft tissue injuries. The cost to society for lost productivity was estimated at 4.4 million Euros during the five-year follow-up. Conclusion: Neck injuries following whiplash trauma arise from both traffic and non-traffic injury events and affect people of all ages. Consequently long-term sick leave occur in a minority of the patients, commonly among older persons and persons injured in traffic. The costs to society from lost productivity is high.