Prognosis in patients with recent onset low back pain
Prognosis in patients with recent onset low back pain in Australian primary care
From: BMJ 2008;337:a171
In this study of patients with acute low back pain in primary care, prognosis was not as favourable as claimed in clinical practice guidelines. Recovery was slow for most patients. Nearly a third of patients did not recover from the presenting episode within a year.
There is evidence that the type of advice given to patients can alter the course of an episode of low back pain. For this reason, most management guidelines recommend that patients should be reassured that they have a favourable prognosis. This recommendation is commonly supported with the statement that 90% of patients recover within six weeks. Such statements, however, might be too optimistic. While patients typically improve rapidly, the risk of developing chronic low back pain (that is, pain persisting for more than three months) is uncertain. Estimates of this risk vary from 2% to 56%.
To provide individualised advice, it is also necessary to consider prognostic factors. All guidelines for low back pain recommend identification of adverse prognostic factors, commonly described as “yellow flags.” Examples of yellow flags include fear of re-injury, leg pain, or low job satisfaction. While all guidelines endorse screening for prognostic factors, there is considerable uncertainty regarding the choice of these factors and their predictive value.
The lack of consensus regarding the prognosis and prognostic factors for recent onset low back pain has been attributed to methodological shortcomings of previous studies. The most common shortcomings are failure to recruit a representative sample of patients and healthcare providers, incomplete follow-up, and inadequate duration of follow-up. Our previous review found only 15 methodologically sound studies, and, of these, only two provided information on outcomes beyond three months. Without accurate data on prognosis and prognostic factors clinicians are unable to provide appropriate information and advice to their patients with acute low back pain.
We conducted a cohort study with the primary aim of determining the long term (one year) prognosis for people with recent onset low back pain presenting to primary care clinicians. Our secondary aim was to identify patients’ characteristics that could be readily assessed by a primary care clinician and were associated with poor prognosis.
In this study of 12 month prognosis in patients with recent onset low back pain, recovery was typically much slower than previously reported. Nearly a third of patients did not recover from the presenting episode within a year. Return to work and recovery from disability and pain did not occur synchronously. We identified seven readily assessed factors that were associated with speed of recovery and can be considered by clinicians when advising their patients about the prognosis for their episode of acute low back pain.
Our findings support the recommendations in clinical practice guidelines that clinicians should screen for adverse prognostic factors (yellow flags). We identified seven factors associated with poor prognosis that could be readily applied in primary care. These results also concur with the view that psychosocial factors are important factors predicting poor outcome. In contrast to most guidelines we found that recovery from low back pain is typically slow and incomplete. The slow and incomplete recovery occurred even though we trained all clinicians in the study to provide best practice care consistent with current clinical guidelines. At the moment it is unclear how better health outcomes can be achieved. Establishing whether it is the endorsed treatments or their implementation that is the problem could help to improve outcomes for acute low back pain.
Recovery did not occur synchronously in the three dimensions of return to work, interference with function, and pain status. Most patients who reduced their work status as a result of their low back pain resumed their pre-back pain work status quickly, but this was not indicative of recovery from an episode of low back pain. The return to pre-injury work hours and duties occurred more quickly and in more participants than recovery from pain or interference with function. Of the three dimensions used to measure recovery, pain took the longest to resolve. In fact the survival curves for recovery from pain and complete recovery were similar. This indicates that the primary impediment to complete recovery is ongoing pain. Nearly a third of the participants had not recovered from the initial episode by 12 months.
Despite widespread investigation, there has been little consensus regarding predictors of outcome from acute low back pain. Rather than testing the predictive value of large numbers of individual variables, as is common practice, we grouped potential predictive variables into discrete factors, controlling for demographic and pain related covariates. While the factors might not have been able to fully describe complex constructs such as culture and psychology, factor items were taken from validated questionnaires. Using this approach we identified seven variables that were independently associated with poor prognosis. Psychological characteristics (feelings of depression and perceived risk of persistence) were most closely associated with time to recovery, while characteristics of the current history (low back pain in compensation cases and duration of episode) were still significantly associated with time to recovery after we accounted for psychological characteristics.
The most obvious use of prognostic information is to provide patient specific estimates of prognosis to individual patients in primary care. The prognostic factors we identified are readily assessed in primary care. That treatment should be targeted towards factors that have an adverse effect on recovery, and our findings provide some insight into how this might be achieved in primary care. For example, as compensation status was the strongest predictor, it might be worth investigating the process of care for a cohort of patients in compensation cases to identify potential causes of delayed recovery. In addition, our findings suggest that effective strategies could be investigated for the assessment and management of symptoms of depression and catastrophising. Further studies are warranted to evaluate the validity of these predictors in other cohorts of patients with acute low back pain in primary care.
What is already known on this topic:
Clinical practice guidelines suggest that recovery from an episode of recent onset low back pain is usually rapid and complete
Recent systematic reviews suggest that the risk of developing chronic low back pain is uncertain
What this study adds:
Recovery from recent onset low back pain was much slower than has been reported and nearly a third did not recover within a year
Older age, back pain associated with compensation cases, higher pain intensity, longer duration of low back pain before consultation, more days of reduced activity because of low back pain before consultation, feelings of depression, and a perceived risk of persistence were all associated with poorer prognosis
