Is time of neck pain onset a prognostic factor in whiplash-associated disorders?

Abstract

Aims: One possible prognostic factor for whiplash-associated disorders which to date has not been investigated, is time of pain onset. We hypothesized that immediate onset of neck pain post-collision may indicate a different origin of the injury, with a prolonged recovery, compared to an injury with delayed onset of neck pain. Therefore, the aim was to investigate this in a prospective cohort study. Methods: Data was collected from insurance claimants (n = 1,308). Questionnaires at baseline provided information on time of neck pain onset, and potential confounders. Exposure was time of pain onset, trichotomized into; at the scene of the collision, 1-12 hours, and >12 hours post-collision. At a 6-month follow-up, pain-related disability was assessed with the pain disability index (PDI) and trichotomized into scores based on the median and the 75th percentile; PDI = 0, 1–18 and >18. Results: Twenty-eight percent of persons with pain onset at the scene of collision rated in the PDI >18 category at follow-up, compared to 21% respectively of those with onset 1–12 hours and those with onset >12 hours post collision. Persons with pain onset at the scene were more likely to rate PDI >18 compared to those with onset >12 hours post-collision. When adjusted for confounders, the result was attenuated and not statistically significant or 1.3 (95% CI; 0.8–2.2). Conclusion: Time of neck pain onset is not a prognostic factor in recovery from whiplash-associated disorders in this study. Further studies are warranted to confirm the results.