Study design: This study examines the links between severity of whiplash associated disorder and costs and health outcomes.
Objective: The study aims to estimate the economic costs and health-state utilities associated with disability levels and recovery trajectories after acute whiplash injury.
Summary of background data: Data used were from the Managing Injuries of the Neck Trial, which collected information on 3851 people over a 12-month period after acute whiplash injury.
Methods: Effects of whiplash associated disorder severity on economic costs (measured from a societal perspective and separately from a health and personal social services perspective) were estimated using two-part regression models, comprising probability of incurring a cost and the total cost, given one was incurred. Effects on health-state utilities (measured using the EQ-5D and SF-6D) were estimated using ordinary least squares regression, and two-part models as for costs.
Results: There was a direct relationship between severity of disability after acute whiplash injury and economic costs. Between baseline and 4 months, average societal costs for those with no disability were £99.55 (UK£, 2009 prices), increasing to £668.53 for those with complete disability. Average societal costs for the whole sample were £234.15 over the first 4 months, decreasing to £127.51 between 8 and 12 months. Conversely, utility scores decreased with increased disability. The average EQ-5D utility score was 0.934 at 4 months for those with no disability, decreasing to 0.033 for those with complete disability. The average EQ-5D utility score for the whole sample increased from 0.587 immediately post-injury to 0.817 at 12 months. Relative costs and disutilities generated by the multivariate models are also presented by disability level and recovery trajectory.
Conclusion: These results provide estimates of the costs and health-state utilities associated with disability levels and recovery trajectories after acute whiplash injury. They can be used to inform estimates of the cost-effectiveness of interventions targeting whiplash-associated disorders.
Level of evidence: 3.