Risk factors for chronic disability in a cohort of patients with acute whiplash associated disorders seeking physiotherapy treatment for persisting symptoms

Objectives: (1) To identify risk factors for chronic disability in people with acute whiplash associated disorders (WAD). (2) To estimate the impact of the numbers of risk factors present. Design: Prospective cohort study. Data were collected, on average, 32 days after injury (SD = 10.9) and 12 months later. Baseline measures of pain, disability, neck movement, psychological and behavioural factors were independent variables and chronic disability at 12 months was the dependent variable in a multivariable logistic regression analysis. Setting: National Health Service physiotherapy departments. Participants: Participants (n = 599) with symptoms 3 weeks after injury, self-referred to physiotherapy as part of a randomised controlled trial. 430 (72%) participants provided complete data for this analysis. Main outcome measures: Chronic disability based on Neck Disability Index scores. Results: 136 (30%) participants developed chronic disability. High baseline disability (OR 3.3, 95%CI 1.97 to 5.55), longer predicted recovery time (OR 2.4, 95%CI 1.45 to 3.87), psychological distress (OR 1.9, 95%CI 1.05 to 3.51), passive coping (OR 1.8, 95%CI 1.07 to 2.97) and greater number of symptoms (OR 1.7, 95%CI 1.07 to 2.78) were associated with chronic disability. One risk factor resulted in 3.5 times the risk (95%CI 1.04 to 11.45) of chronic disability but this risk increased to 16 times (95%CI 5.36 to 49.27) in those with four or five risk factors. Conclusion: Baseline disability had the strongest association with chronic disability but psychological and behavioural factors were also important. Treatment strategies should reflect this which may require a change to current physiotherapy approaches for acute WAD. The number of risk factors present should be considered when evaluating potential for poor outcome.