Identifying predictors of early non-recovery in a compensation setting: The Whiplash Outcome Study

Abstract

Context

People with Whiplash Associated Disorder (WAD) often experience pain and disability for extended periods of time. A large proportion of these people will seek treatment through a compensation process. Rarely is data related to people's health collected within the compensation process making it difficult to identify those that are at risk of delayed recovery and appropriately direct interventions.

Study objective

To compare people with WAD who have recovered with those that have not, within 3 months of injury and identify potential predictors of poorer health and non-recovery to inform claim screening processes.

Study design

Cross-sectional analysis of a cohort study.

Participants

People who sustained a WAD and claimed compensation within an Australian Motor Accidents Compensation Scheme between November 2007 and June 2009.

Measure of recovery

Functional Rating Index (FRI) score (≤25).

Health outcome measures

Short Form 36 (SF36), FRI, and the Pain Catastrophising Scale (PCS).

Methods

246 people who had lodged a claim for compensation were enrolled in the Whiplash Outcome Study within 3 months of sustaining a WAD injury. Participants were assigned to a recovered or non-recovered group and analysed for differences between the two groups. Multiple linear regression models were used to identify potential predictors of poorer health and non-recovery.

Results

Overall 23% of the study population had recovered within 3 months of sustaining a WAD, whilst only 9% had finalised their insurance claim. The recovered group had significantly better scores on all health outcome measures; SF36 Physical Component Score, SF36 Mental Component Score and the PCS (p < 0.001). The significant independent predictors of poorer health and non-recovery were helplessness (p < 0.001), older age (p < 0.001) and pre-injury work status being affected (p < 0.001) (r² = .624). Regardless of the health outcome measure used, helplessness was significantly associated with poorer reported health.

Conclusion

Including additional information at claim notification, specifically the PCS and information on the effect the injury has on the working population could significantly improve claim screening processes, identifying those with poorer health and risk of non-recovery.

Introduction

Whiplash Associated Disorders (WAD) are the most common injury type sustained following motor vehicle crashes²⁷ and as such constitute a large proportion of compensation scheme costs in jurisdictions where compensation is available. The incidence of WAD has increased over the past 30 years and is likely to be at least 300 per 100,000 inhabitants in some countries.¹⁷ The number of claims for compensation also varies amongst countries and compensation schemes, reports have been as high as 600 per 100,000 inhabitants.⁸

The Bone and Joint Decade 2000–2010 Task Force on Neck Pain and its Associated Disorders recently reported that recovery from WAD is protracted with only half those affected reporting no neck symptoms 1 year after the motor vehicle crash.¹⁸ This is consistent with the findings of an Australian Study where only 50% of the study population had recovered at the time of the Study's 2-year follow-up.²⁵ Measuring recovery from WAD is inconsistent, with only a small number of studies using a validated measurement instrument¹⁹ such as the Functional Rating Index²⁵ and the Neck Disability Index.²⁸ Studies that have used proxies for recovery, typically claim finalisation have reported higher recovery rates.³⁰

Previous research has been contradictory with respect to determinants of delayed recovery. One systematic review found that age, gender, initial pain intensity and radicular symptoms were predictors of outcome,⁹ whilst another review agreed that high initial pain intensity was predictive of outcome but found age and gender were not.²⁶ More recently, the best evidence synthesis of The Bone and Joint Decade 2000–2010 Task Force on Neck Pain and its Associated Disorders concluded that recovery is slower in those WAD sufferers with higher symptom severity and that post-injury psychological distress and passive coping was prognostic of poor recovery.⁷

A large proportion of people with WAD obtain treatment and intervention through a compensation process where there is mounting evidence to suggest that being part of that process is associated with poorer outcomes.12, 15, 2 Identifying those who are least likely to recover as early as possible within that process becomes increasingly important so resources may be directed appropriately.

In New South Wales (NSW), Australia, motor accident insurance is compulsory and is provided on a “fault-basis”, for those who have been injured as a result of the fault of another person. Some important features of the NSW Scheme include; provisions for early notification and treatment through speedy and simplified accident notification and provisional liability provisions, and a threshold to access common law damages (non-economic loss payments) which is determined by an objective medical assessment process. Claims for whiplash do not typically meet the threshold.

The Whiplash Outcome Study (WOS) is based in NSW, where claims for WAD are a significant component of the NSW Motor Accidents Scheme with 45% of all claims involving a whiplash injury, contributing 27% of the total claims cost in that Scheme.²¹

This paper describes those people with WAD who had not recovered within 3 months following their crash and aims to identify potential predictors of poorer health and non-recovery. In particular, the approach is to identify data which, if collected at claim notification, could assist in the development of screening processes and informing targeted interventions that can be applied by Insurers and Compensation Scheme policy makers.