Risk Factors for Persistent Problems Following Whiplash Injury: Results of a Systematic Review and Meta-analysis.
From: J Orthop Sports Phys Ther. 2009 May;39(5):334-50
Whiplash following motor vehicle collision is a condition with substantial social and, in many cases, personal cost. Whiplash is defined as an acceleration-deceleration mechanism of energy transfer to the neck, resulting from rear-end or side-impact collisions but also from diving or other mishaps.
Whiplash associated disorder is the most common reported injury following motor vehicle accident. Evidence for prognosis and intervention are difficult to interpret due to differences in inception times, outcomes used, and sample heterogeneity.
An extensive literature search was conducted to identify published studies of prognosis following whiplash. Rigorous inclusion criteria were applied to allow for meaningful results to be drawn. Data were extracted, transformed where necessary, and pooled to allow estimation of the odds ratio for any factor with at least 3 data points in the literature.
From 11 cohorts (n = 3193), 25 factors were identified with at least 3 data points in the existing literature. Of these, 9 were found to be significant predictors based on the odds ratio and confidence limits: no postsecondary education, female gender, history of previous neck pain, baseline neck pain intensity greater than 55/100, presence of neck pain at baseline, presence of headache at baseline, catastrophizing, whiplash associated disorder grade 2 or 3, and no seat belt in use at time of collision. Neck pain intensity, whiplash associated disorder grade, headache, and no postsecondary education were robust to publication bias.
Using a rigorous process for the identification and extraction of data from a homogenous subset of the prognostic whiplash associated disorder literature, we were able to identify several factors for which information is easy to collect clinically and could provide clinicians with a good sense of prognosis following whiplash injury.
The initial assessment should document the presence of the following factors:
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Variables with strong evidence of a significant effect
- High baseline neck pain intensity (greater than 55/100)
- Presence of headache on intake
- Whiplash associated disorder grade 3 (compared to grade 2, when outcome is captured 12 mo postinjury)
- No postsecondary education
- Whiplash associated disorder grade 2 or 3 (compared to grade 0 or 1, when outcome is captured 12 mo postinjury)
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Variables with moderate evidence of a significant effect
- Catastrophizing
- Presence (yes/no) of neck pain at intake
- No seat belt in use at time of accident
- History of neck pain prior to the accident
- Female
The authors recommend that documentation, particularly documentation provided to payers, reference this meta-analysis to indicate the source of evidence and provide an indication of evidence-based practice. They additionally recommend that the following statement be included wherever statements listed are used: “Patients often have 1 or more risk factors that affect their outcome. The evidence available at this time indicates how to interpret single risk factors in the way we have in this assessment. The evidence does not provide direction on how to interpret multiple factors at this time. It cannot be assumed that multiple risk factors are directly additive, but evidence suggests that having multiple risk factors does increase risk in most cases”.
