by Mark Boyland, PT, DPT

This meta-analysis explored the prognostic factors which can predict outcomes for patients with acute whiplash injuries.  As a disclaimer this study was meant to identify the factors only and not what scales or intensity would lead to prognostic factors.  The authors note that it is beyond the scope of their study to examine specific quantitative data regarding prognosis.  This concept will be discussed later in this summary.  I had two major takeaways from this piece: 50% of people who suffer from whiplash will have long term negative impacts, and that whiplash related pain and anxiety after a car accident are the most consistent prognostic factors for having long term negative impacts on their function.  Other factors that were prognostic included catastrophizing, compensation and legal factors, and early use of health care.  The authors did not identify what levels of pain or anxiety were more prognostic.  The authors did not identify the amount of compensation or specific measures of legal factors.  While a knee jerk reaction may be to say that people who have significant pain and anxiety who also get legal counsel quickly involved will have long term disability but that was not the focus of this paper and this assumption cannot be made based on the information provided.  Please read on to find out what factors were not associated with long term impact or required further research to establish the type of connection.

This meta-analysis was relatively sizeable in terms of the amount of studies analyzed and the number of patients which were included across all studies reviewed.  The authors analyzed 12 systematic reviews of moderate quality.  Each systematic review analyzed anywhere from 6 to 38 studies for a total of 200 studies which included over 99,000 patients.  The studies examined ranged from 1980-2012 and the meta-analysis was published in a 2017 journal.  Being able to look at over 20 years of research and explore nearly 100,000 patients is an achievement and does bring a little more merit to a relatively common population.

The study was funded by the Motor Accident Authority (MAA) of New South Wales, Australia.  However, the funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.  So why study acute whiplash injuries?

Whiplash is among the leading car crash related injuries in terms of burden on patients, to the healthcare system, and on insurance organizations.  Whiplash type injuries have been increasing over the past decade, and patterns of car accidents that causes whiplash have also changed and now include minor types of accidents.  The overall increase in whiplash may also be due to rise in traffic density and changes in societal and litigation factors but was not part of this paper’s exploration.  The authors examined potential prognostic factors and separated these factors into 4 categories: associated, non associated, lack of evidence, and controversial.  Associated factors were defined as those which found adequate evidence to conclude that a factor was associated with the outcome of acute whiplash injury.  Non associated was the opposite.  A lack of evidence was unable to identify adequate evidence regarding a prognostic factor.  Controversial factors were those which had conflicted evidence.

As mentioned earlier, the authors found the following as associated factors for predicting outcomes: post injury pain and disability, post-injury anxiety, catastrophizing, compensation and legal factors, early use of health care.  The most consistent finding was the association of post injury pain and disability with long term pain and disability.  The association of other factors was not as strong although the association of psychosocial factors with whiplash is notable.

Interestingly enough post injury MRI/X-ray findings, motor dysfunctions, or factors related to the collision were not associated with continuation of pain and disability in patient’s whiplash.  Factors related to the collision were more related to speed of collision or direction of impact.

However, evidence on demographics and 3 psychological factors and prior pain was conflicting and there is a shortage of evidence related to the significance of genetic factors.

Overall this meta review suggests an association between initial pain and anxiety and the outcome of acute whiplash injury, and less evidence for an association with physical factors.  To critically re-emphasize, this paper only sought to identify prognostic factors but not the scales or intensity of these factors.  This would be an opportunity for additional research.  There is a limited number of studies which examines prognosis of whiplash based on: occupation type, disc degeneration, pre-existing /new widespread body pain/fibromyalgia, or pre-injury fitness or exercise levels.  As humans we are incredibly complex individuals when you consider what makes us ‘us’ and to determine consistent patterns that can fit specific populations is difficult.  While the findings of this paper are unsurprising that having whiplash related pain is a factor for long term whiplash related pain, being able to identify factors which are not prognostic is also helpful.