Risk Factors for Disability with Low Back Pain
The problem of low back pain continues to be the topic of many research efforts. Studies so far have shown that psychosocial factors (e.g., work status, mental health, level of education, blaming work for pain) are linked with pain, disability, and failure to return-to-work.
But are there other, more clinical risk factors for ongoing (chronic) low back pain and/or disability? This large study from Denmark suggests there are indeed other factors to consider.
Some of the predictive risk factors still fall under the heading of psychosocial such as worrying about health and worry in general. Others are lifestyle choices that can be modified including drinking less than one drink per month and a lack of regular exercise.
The year-long study included 325 men and women who were off work for at least three weeks (and up to 16 weeks) with either just back pain or back and leg pain. Leg pain signifies nerve irritation called radiculopathy. The underlying cause of the pain was disc degeneration (confirmed by X-rays and MRI).
The authors were particularly interested in breaking down the results to look at the link between disability and pain after one year, just disability at one year, change in disability during the same year-long follow-up, and change in back and leg pain. They also looked at how many patients were able to go back to work and percentages for each group (back pain only, back and leg pain).
Almost 40 different variables were examined looking for an association between each one and the outcomes (main outcomes being disability, intensity of pain, return-to-work). They decided not to limit the outcomes based on pain because many people press on and function normally despite their pain. So although pain contributes to disability, it isn't always a good measure of disability. Function during daily and work activities is a better gauge of ability/disability.
Some of the factors investigated included age, body mass index, presence of tender points, intensity and duration of pain, use of pain medication, compensation claim pending, marital status, any children, type of job, personal/family income, and level of education or vocational training. Use of tobacco, alcohol, and physical activity and exercise were also measured. Worry, mental distress, depression, and anxiety were included in the comparisons.
At the end of one year, two-thirds of the patients had returned to work while almost 20 per cent were still off work on sick-leave. The rest were either training for another job, working part-time, retired, or going back to school. For those who did go back to work, there was an equal number treated for their low back pain with a multidisciplinary approach versus a short intervention program.
As suspected, a change in disability (not a change in pain) was a greater predictor of return-to-work status. Those who were able to go back to work reported less overall pain and tested at a higher functional level than those who remained on sick-leave. Tender points throughout the body and lack of leisure activity or exercise were common in patients who still had pain and disability a year after treatment. Higher level of disability and lower change in disability were observed in patients with a Worker's Compensation claim.
What do the results of this study suggest? First, exercise remains a top priority for getting people with chronic low back pain back to work. For those who remain on sick-leave, there is evidence that a traditional physiotherapy program is not as effective as graded activity. With graded activity, improving function (not reducing pain) is the focus. Exercises are geared around function at home and at work.
Worry and anxiety seems to play a key role in patients' perceptions (how they view themselves). Behavioral or cognitive therapy might be helpful. Being older and overweight were two factors present in patients who did not return-to-work at all.
Older adults and those who don't drink were also more likely to experience continued disability a year after treatment for low back pain. Does that mean workers still on sick-leave for low back pain after a year should drink more?
Probably not. It's more likely an indication that their level of stress and mental distress is higher than in patients who drink more. The authors suggest that there may be a biologic explanation for this difference. Either way, more study is needed to understand the association between alcohol, disability, and return-to-work before specific recommendations are made.
In summary, the results of this study confirmed what is already known about psychosocial factors being linked with chronic low back pain, disability, and failure to return-to-work (i.e., remaining on sick-leave). Some additional risk factors were added to the list: lack of exercise, diffuse tender points at the start of the treatment, older age, and drinking less than once a month.
Reference: Ole Kudsk Jensen, MD, et al. One-year Prognosis in Sick-Listed Low Back Pain Patients With and Without Radiculopathy. Prognostic Factors Influencing Pain and Disability. In The Spine Journal. August 2010. Vol. 10. No. 8. Pp. 659-675.