Risk factors for prolonged disability after whiplash injury: a prospective study.

STUDY DESIGN: A prospective study of 135 patients with whiplash injury.

OBJECTIVES: To identify factors predictive of prolonged disability following whiplash injury.

SUMMARY OF BACKGROUND DATA: Although patients with whiplash associated disorders lack demonstrable physical injury, many exhibit prolonged disability. Disability appears unrelated to the severity of the collision.

METHODS: A total of 147 patients with recent whiplash injury were interviewed for putative risk factors for disability, and 135 were reinterviewed 12 months later to assess degree and duration of disability. Bivariate and multivariate analyses were undertaken to measure the association between putative risk factors and measures of outcome (change in Neck Pain Outcome Score [NPOS] and visual analogue pain score [VAPS], return to work, still requiring treatment, settlement of claim).

RESULTS: The bodily pain score and role emotional scores of the Short Form-36 health questionnaire showed a consistent significant positive association with better outcomes. After adjustment for bodily pain score and role emotional scores, consulting a lawyer was associated with less improvement in NPOS (P < 0.05), but there was no association with change in VAPS. Consulting a lawyer was associated with a lesser chance of claim settlement (P < 0.01) and a greater chance of still having treatment (P < 0.01) after 1 year, but there was no significant association with a return to work. The degree of damage to the vehicle was not a predictor of outcome.

CONCLUSIONS: Short Form-36 scores for bodily pain and role emotional are useful means of identifying patients at risk of prolonged disability. The findings support the implementation of an insurance system designed to minimize litigation.