Background: Individuals' expectations on returning to work after an injury have been shown to predict the duration of time that a person with work-related low back pain will remain on benefits; individuals with lower recovery expectations received benefits for a longer time than those with higher expectations. The role of expectations in recovery from traumatic neck pain, in particular whiplash-associated disorders (WAD), has not been assessed to date to our knowledge. The aim of this study was to investigate if expectations for recovery are a prognostic factor after experiencing a WAD.
Methods and findings: We used a prospective cohort study composed of insurance claimants in Sweden. The participants were car occupants who filed a neck injury claim (i.e., for WAD) to one of two insurance companies between 15 January 2004 and 12 January 2005 (n = 1,032). Postal questionnaires were completed shortly (average 23 d) after the collision and then again 6 mo later. Expectations for recovery were measured with a numerical rating scale (NRS) at baseline, where 0 corresponds to "unlikely to make a full recovery" and 10 to "very likely to make a full recovery." The scale was reverse coded and trichotomised into NRS 0, 1-4, and 5-10. The main outcome measure was self-perceived disability at 6 mo postinjury, measured with the Pain Disability Index, and categorised into no/low, moderate, and high disability. Multivariable polytomous logistic regression was used for the analysis. There was a dose response relationship between recovery expectations and disability. After controlling for severity of physical and mental symptoms, individuals who stated that they were less likely to make a full recovery (NRS 5-10), were more likely to have a high disability compared to individuals who stated that they were very likely to make a full recovery (odds ratio [OR] 4.2 [95% confidence interval (CI) 2.1 to 8.5]. For the intermediate category (NRS 1-4), the OR was 2.1 (95% CI 1.2 to 3.2). Associations between expectations and disability were also found among individuals with moderate disability.
Conclusions: Individuals' expectations for recovery are important in prognosis, even after controlling for symptom severity. Interventions designed to increase patients' expectations may be beneficial and should be examined further in controlled studies.