Prognostic factors associated with minimal improvement following acute whiplash-associated disorders.

STUDY

DESIGN

Retrospective clinical cohort study.

OBJECTIVE

To identify the prognostic factors associated with a poor response to treatment in the early stages of a whiplash-associated disorder (WAD).

SUMMARY OF BACKGROUND DATA: Several demographic and clinical factors related to recovery following acute WADs have been identified. However, few longitudinal studies have investigated a multivariable model of recovery that includes socio-demographic, treatment, clinical, and nonclinical factors.

METHODS

A study cohort of 2,185 patients with acute or subacute WADs presenting to 48 rehabilitation clinics in 6 Canadian provinces were investigated for factors associated with failure to demonstrate a minimally important clinical change (10%) in the Canadian Back Institute Questionnaire (CBIQ) score between the initial and discharge rehabilitation visits.

RESULTS

Multivariable analysis revealed eight prognostic factors associated with a negative outcome: 1) older age, 2) female gender, 3) increasing lag time between injury date and presentation for treatment, 4) initial pain location, 5) province of injury, 6) higher initial pain intensity, 7) lawyer involvement, and 8) at work at entry to the clinic. The effect of lawyer involvement was stronger for patients with less intense pain on initial visit (odds ratio = 2.97; 95% confidence interval, 1.77-4.99). Similarly, the effect of work status was stronger for patients with less intense pain on initial visit (odds ratio = 2.02; 95% confidence interval, 1.18-3.46).

CONCLUSIONS

Researchers and clinicians should be aware of the potential for non-injury-related factors to delay recovery, and be aware of the interaction between the initial intensity of a patient's pain and other covariates when confirming these results.