Research Review by Dr. Kent Stuber©

Date:

Aug. 2008

Study Title:

  1. Course and prognostic factors for neck pain in the general population: Results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and its Associated Disorders.
  2. Course and prognostic factors for neck pain in Whiplash Associated Disorders (WAD): Results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and its Associated Disorders.

Authors:

  1. Carroll LJ, Hogg-Johnson S, van der Velde G, et al.
  2. Carroll LJ, Holm LW, Hogg-Johnson S, et al.
Authors’ Affiliations:
The Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders.
  • Carroll – Department of Public Health Sciences, and the Alberta Centre for Injury Control and Research, School of Public Health, University of Alberta
  • Hogg-Johnson - Institute for Work and Health, Toronto; Department of Public Health Sciences, University of Toronto
  • van der Velde – Department of Health Policy, Management and Evaluation, University of Toronto; Institute for Work and Health, Toronto; Centre for Research Excellence in Improved Disability Outcomes (CREIDO) University Health Network Rehabilitation Solutions, Toronto Western Hospital; Division of Health Care and Outcomes Research, Toronto Western Hospital Research Institute
  • Holm – Institute of Environmental Medicine, Karolinska Institutet

Publication Information:

  1. Spine 2008; 33(4S): S75-82.
  2. Spine 2008; 33(4S): S83-92.

Summary:

Course and Prognostic Factors for Neck Pain in the General Population

The course of a condition is whether it is likely to improve, recur, persist, or worsen. The prognostic factors of a condition are those factors that determine the condition’s course. Prognostic factors can be either modifiable or non-modifiable. The Neck Pain Task Force looked at the longitudinal studies of prognostic factors by placing included articles into one of three categories:
  1. Phase I studies – look at associations between prognostic factors and health outcomes in a descriptive sense (for example age and recovery from neck pain).
  2. Phase II studies – use more extensive analysis, but still look on an exploratory basis. Use a more robust sampling and analysis method to focus on sets of prognostic factors (age, gender, mental and physical status and frequency of exercise in a multivariable analysis to predict recovery from neck pain.
  3. Phase III studies – a confirmatory study, attempt to test a specific hypothesis that an association or relationship exists (or doesn’t) between a particular prognostic factor and the outcome of interest. Great lengths are taken to control for confounders.
The NPTF included 70 articles on the topic of prognostic factors for neck pain into their analysis and best evidence synthesis. 6 studies on the course of neck pain in the general population were admitted into the best evidence synthesis. According to these studies between 50-85% of people with neck pain at some point will report neck pain 1 to 5 years later.

7 studies on prognostic factors for neck pain in the general population were admitted. In Phase I studies, men were one third to nearly 50% more likely to have complete resolution of neck pain over a 1-year and five-year follow-up period respectively and women were nearly 20% more likely to have persistent pain, according to one study. Phase II studies conducted thus far have not confirmed this Phase I finding. The NPTF concluded that gender is a weak predictor of recovery from neck pain. Younger age is a consistently better prognostic factor for neck pain in the general population according to several Phase I and II studies.

The highest risk and poorest prognosis for neck pain appears to be during the middle aged years according to one study but this requires further confirmatory studies. Prior health and pain-related factors are prognostic of neck pain according to Phase II and Phase I studies. Factors such as initial pain intensity, duration, and pain-related difficulties, prior neck pain, co-morbid low back pain, and poor general health were found to be predictive of the presence and/or greater intensity of neck pain at follow-up.

Of note was the finding that there was no evidence of degenerative changes as a prognostic factor in recovery from neck pain (a notion commonly dispensed by clinicians to patients, intimating that degeneration indicates a poorer prognosis or longer recovery time).

Lack of employment at baseline indicates a higher likelihood of reporting pain at a similar frequency at follow-up than those employed at baseline. No other workplace factors appear to be predictive of neck pain at one year follow-up. Psychological factors are important in neck pain outcome in the general population.

Phase II and III studies indicate that passive coping is associated with poorer outcome as is anger or frustration. Vitality, greater social support, optimism, self-reliance, and self-assured coping are predictive of better outcomes. An association seems to exist between poor psychological health and persistent pain. People with a higher external locus of control were slightly more likely to have a reduction in headache frequency when receiving manipulation/exercise than medication. Pretreatment depression has not been found to affect pain intensity reduction at 1 year.

The NPTF did not admit any studies on societal factors such as compensation or other legal/policy related concepts on the prognosis of neck pain, nor did they admit any studies of genetic factors on the prognosis of neck pain. The evidence is conflicting with respect to the prognostic value of exercise or physical activity in the outcome of neck pain. Most factors that predict poor outcome are similar to those that increase the risk for neck pain. There is hardly an overwhelming amount of literature on this topic and further Phase II and III studies are certainly required.

Course and Prognostic Factors for Neck Pain in Whiplash-Associated Disorders

It is important for clinicians to remember that whiplash is the injury mechanism whereas WAD (Whiplash-Associated Disorder) is the symptom-cluster resulting from the injury as per the Quebec Task Force. Neck pain after motor vehicle collisions are unfortunately common, 300 people per 100,000 in the population are seen in the emergency room for such injuries every year (one only has to think of a city the size of the Greater Toronto Area to think of the number of people affected).

The NPTF included 70 articles on the topic of prognostic factors for neck pain into their analysis and best evidence synthesis. 47 studies on the course and prognostic factors of neck pain in WAD were among these admitted into the best evidence synthesis (20 on course and 29 on prognostic factors, and 3 systematic reviews, with some relating to more than one topic). Studies were again categorized into the Phase I – II – III scheme as noted above.

With respect to the course of WAD, recovery from WAD is generally prolonged with over half of those affected reporting symptoms one year after their injury according to most of the involved literature. WAD can recur or persist in the long term, with up to 58% of patients still having some symptoms due to their injury up to 2.5 years later and many still having neck pain 7 years after the initial injury. People with prior WAD are more likely to have more generalized pain, poor overall health, sleep problems, and fatigue at extended follow-up. Fortunately, what little research there is on the course of WAD in children indicates that they generally recover rapidly.

Women tend to have less complete recovery from WAD than males, and there appears to be a modest association for gender as a prognostic factor for recovery from WAD. There is disagreement in the literature as to whether age is a significant prognostic factor for WAD, although some studies show that older people tend to have slower recovery. The evidence is inconclusive and conflicting with respect to education level as a prognostic factor for recovery from WAD. The evidence is also inconclusive with respect to the role of pre-injury health or pain levels. Collision related factors (such as speed differential, awareness of likelihood of impact, position in the vehicle, headrest use, seatbelt use) are generally not predictive of recovery in WAD. Having a tow bar was somewhat predictive of poorer prognosis.

Patients with Grade III WAD recovered more slowly than those with Grade I WAD (which seems self-explanatory). Increasing grade of WAD is generally predictive of longer recovery or poorer prognosis.

People with more frequent or severe symptoms or higher pain intensity have poorer prognosis for recovery from WAD. Psychologic factors are prognostic of recovery in WAD with passive coping skills tending to indicate slower recovery as does possession of symptoms of depression. Feelings of helplessness are also prognostic of poorer recovery, as are fear of movement, catastrophizing, and post-injury anxiety. There were no studies on genetic factors and recovery from WAD that were admitted by the NPTF, nor were there any studies included on cultural factors.

Outstanding compensation and ongoing legal (i.e. litigation) factors are unfortunately prognostic factors for recovery from WAD. Claims take longer to resolution in tort insurance systems (versus no-fault systems). Seeking legal advice was associated with delayed claim closure.

There is no suitable evidence with respect to pre-injury fitness or exercise level on recovery from WAD. Frequent early health care use after injury (within the first month) is prognostic of poorer recovery. Those with more frequent visits, those seeing chiropractors (alone and in combination with general practitioners) and specialists (in combination with general practitioners) had slower recovery.

Conclusions & Practical Application:

Having knowledge of important prognostic factors can help guide expectations for recovery for both clinicians and patients, and when these factors are modifiable, can guide considerations for intervention. It is essential that clinicians attempt to identify treatments and interventions that will help reduce the natural history or course of neck pain.

Unfortunately, none of the prognostic factors examined by the NPTF had extremely large effects; several were modest predictors of prognosis at best (as summarized below). For numerous factors there is conflicting evidence which does not allow for a firm conclusion to be reached indicating that further research is going to be necessary. For other factors there is simply no suitable evidence available at all (as discussed above). Recovery from WAD and from neck pain in the general population is multi-factorial and the exact nature and extent of the contributions of the various important factors still needs to be determined.

It is important for clinicians to know and understand which factors may be involved in helping determine the prognosis of their patients. It is equally important to know which factors are NOT involved in determining prognosis – some of these factors may be surprising to clinicians who have learnt through education, rumor, etc that these particular factors were important when in actual fact they are not.

Factors Associated with Prognosis for General Population with Neck Pain
  • Gender
  • Age (but not degeneration)
  • Prior health
  • Pain-related factors
  • Employment
  • Psychological factors
Factors with Conflicting Evidence of Association with Prognosis for General Population with Neck Pain
  • Exercise or physical activity
  • Pre-treatment depression
Factors Associated with Prognosis in WAD
  • Gender
  • Grade of WAD
  • Frequent, severe symptoms, higher pain intensity
  • Psychologic factors
  • Compensation and litigation
  • Frequent, early health care use
  • Having a tow bar
Factors with Conflicting Evidence of Association with Prognosis in WAD
  • Age
  • Education level
  • Pre-injury health or pain levels
  • Collision-related factors
  • Pre-injury fitness or exercise level