Long-term follow-up of whiplash injuries reported to insurance companies: a cohort study on patient-reported outcomes and impact of financial compensation.

Purpose: The long-term outcome of Whiplash-associated disorder (WADs) has been reported to be poor in populations from medical settings. However, no trials have investigated the long-term prognosis of patients from medico-legal environment. For this group, the "compensation hypothesis" suggests financial compensation being associated with worsened outcome. The aims of this study were to describe long-term (2-4 years) non-recovery rates in participants with WAD recruited from insurance companies and to investigate the association between self-reported non-recovery and financial compensation.

Methods: 144 participants, reporting neck pain after a motor vehicle accident, were recruited from two major insurance companies in Sweden. Self-reported recovery was measured at 6 months and 2-4 years. Those who received financial compensation from an insurance company were compared with those who received no compensation.

Results: The overall non-recovery rate after 2-4 years was 55.9% (66/118). In the non-compensated group, the non-recovery rate was 51.0% (25/49) and in the compensated group 73% (27/37) (p = 0.039). Adjusted OR was 4.33 (1.37-13.66). High level of pain at baseline was a strong predictor of non-recovery [OR 46 (4.7-446.0)]. However, no association was found between pain level at baseline and financial compensation.

Conclusions: The non-recovery rate among patients making insurance claims is high, especially among those receiving financial compensation even if causal relationship cannot be determined based on this study. However, lack of association between baseline level of pain and compensation supports the compensation hypothesis.