Beliefs about back pain and associations with clinical outcomes: a primary care cohort study

Objective To investigate associations between beliefs about low back pain (LBP) at baseline and pain intensity and disability at 2-week, 13-week and 52-week follow-up. Design Observational cohort study. Setting Primary care private chiropractic clinics in Denmark. Participants A total of 2734 adults consulting a chiropractor for a new episode of LBP, with follow-up data available from 71%, 61% and 52% of the participants at 2, 13 and 52 weeks, respectively. Outcome measures Beliefs about LBP were measured by the Back Belief Questionnaire (BBQ) before consulting the chiropractor. Pain (Numerical Rating Scale 0-10) and disability (the Roland-Morris Disability Questionnaire) were measured at baseline and after 2, 13 and 52 weeks. Associations were explored using longitudinal linear mixed models estimating interactions between BBQ and time, and by estimating associations between single items of BBQ and 13-week outcomes. Results More positive beliefs about LBP were weakly associated with a reduction in pain at 2 weeks (beta interaction BBQ#Time=-0.02 (95% CI -0.04 to -0.001)), at 13 weeks (-0.03 (95% CI -0.05 to -0.01)) and at 52 weeks of follow-up (-0.03 (95% CI -0.05 to -0.01); p=0.003). For disability, the association was uncertain (p=0.7). The item 'Back trouble means periods of pain for the rest of one's life' had the strongest association with both reduction in pain (-0.29, 95% CI -0.4 to -0.19, p<0.001) and disability (-2.42, 95% CI -3.52 to -1.33, p<0.001) at 13-week follow-up. Conclusion Positive beliefs regarding LBP, measured by the BBQ, were associated with a reduction in pain intensity at both short-term and long-term follow-up. However, the association was weak, and the clinical relevance is therefore questionable. No clear association was demonstrated between beliefs and disability. This study did not show promise that back beliefs as measured by the BBQ were helpful for predicting or explaining the course of LBP in this setting.