Background context: Previous research has documented various psychosocial risk factors with influence on outcome in low back pain (LBP) patients, but the value of clinical predictors has been less well documented.
Purpose: To identify clinical and psychosocial risk factors at baseline influencing disability and pain at 1 year in LBP patients sick-listed 3 to 16 weeks, and to look for differences between nonspecific LBP and radiculopathy.
Study design: Cohort study with 1-year follow-up based on a randomized clinical trial.
Outcome measures: Disability and change of disability, pain and change in pain at 1 year.
Methods: In a randomized clinical study evaluating multidisciplinary versus brief intervention, 325 patients were followed for 1 year. At baseline, they completed a questionnaire and went through a clinical low back examination, including measure of forward flexion and side flexion as well as tender point examination, a method to estimate diffuse tenderness. Furthermore, degenerative changes on plain X-rays of the lumbar spine were quantified, and sciatica was investigated by magnetic resonance imaging.
Results: Radiculopathy was verified by magnetic resonance imaging in 111 (34%) patients. At 1 year, questions of disability in daily life activities and pain were answered by 60% and 67%, respectively. The intensity of back+leg pain and disability was closely correlated. Statistically significant predictors for both disability and back+leg pain at 1 year were intensity of back+leg pain, worrying and health anxiety, many tender points, and little or moderate exercise in leisure time. Two additional risk factors were identified in patients with radiculopathy: older age and "drinking alcohol less than once per month." Furthermore, disability at 1 year was associated with initial disability and compensation claim, and back+leg pain at 1 year was associated with fear avoidance about physical activity and the duration of pain. Change in disability was more closely associated with return to work than change in pain. Disc degeneration was not associated with disability or pain at 1 year. General health was not statistically significantly associated with outcome when adjusted for back+leg pain, disability, and worrying and health anxiety.
Conclusions: Disability and pain at 1 year were associated with baseline disability and pain, diffuse tenderness, worrying and health anxiety, compensation claim, fear avoidance, and baseline exercise habits. Only in patients with verified nerve root affection, older age, and restrained alcohol seemed to play a role. The multivariate models were insufficient in predicting disability and pain, partly because disability and pain were also strongly associated with return to work.
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