Risk factors of poor prognosis after whiplash injury

Abstract

Whiplash, a common injury following motor vehicle crashes, is associated with high costs and a prognosis that is variable and difficult to predict. In this paper, we review findings from the Quebec cohort epidemiological study on predictive factors of recovery from whiplash injury after a motor vehicle crash. We formed a population-based incident cohort of all 4,759 individuals who sustained a whiplash injury resulting from a motor vehicle crash in the province of Quebec, Canada, in 1987, and followed these patients for up to seven years. The data were obtained from the universal automobile insurance plan (SAAQ) that covers all seven million residents of the Province for all vehicular-related injuries. From this cohort, we formed the cohort of 3,014 for whom a police report was completed. For this cohort, we obtained data on crash-related factors directly from the police report. We also formed the cohort of 2,627 subjects who had strictly a whiplash injury, without associated injuries. For this cohort, the data on signs and symptoms were obtained from the medical charts kept by the SAAQ. For both cohorts, data on the outcome, the recovery time from whiplash, was obtained from the SAAQ databases. The crash-related cohort study found that socio-demographic factors associated with a longer recovery from whiplash include older age, female sex, having dependents and not being employed full time and that each decreases the rate of recovery by 14 to 16 per cent. Factors related to the crash conditions indicate that being in a truck or bus, with a decrease of 52% in the rate of recovery, being a passenger in the vehicle (15%), colliding with a moving vehicle (16%), and a side or frontal collision (15%) all decrease the rate of recovery. We introduce a combined risk score that predicts longer recovery. In the cohort of subjects with signs and symptoms, the median recovery time was 32 days and 12% of subjects had still not recovered after 6 months. The signs and symptoms that were found to be independently associated with a slower recovery from whiplash, besides female gender and older age, were neck pain on palpation; muscle pain; pain or numbness radiating from neck to arms, hands or shoulders; and headache. Together, the presence of all these factors in females aged 60 predicted a median recovery time of 262 days, compared with 17 days for younger males aged 20 who do not have any of these factors. In contrast, using the Quebec classification of signs and symptoms, the median recovery time varied from 17 to 123 days. We conclude that several socio-demographic and crash-related factors, as well as several signs and symptoms, including a combination of specific musculoskeletal and neurological ones that whiplash patients present with, are predictive of a longer recovery period. These patients should be targeted for an early intervention programme aimed at managing whiplash patients with a poor prognosis.