The associations of depression, anxiety, and insomnia at baseline with disability at a five-year follow-up point among outpatients with chronic low back pain: a prospective cohort study

BACKGROUND: No previous study has investigated the associations of depression, anxiety, and insomnia at baseline with disability at a five-year follow-up point among outpatients with chronic low back pain (CLBP). The study aimed to simultaneously compare the associations of depression, anxiety, and sleep quality at baseline with disability at a 5-year follow-up point among patients with CLBP. METHODS: Two-hundred and twenty-five subjects with CLBP were enrolled at baseline, and 111 subjects participated at the five-year follow-up point. At follow-up, the Oswestry Disability Index (ODI) and total months of disability (TMOD) over the past five years were used as the indices of disability. The depression (HADS-D) and anxiety (HADS-A) subscales of the Hospital Anxiety and Depression Scale and the Insomnia Severity Index (ISI) were used to assess depression, anxiety, and insomnia at baseline and follow-up. Multiple linear regression was employed to test the associations. RESULTS: The scores of the HADS-D, HADS-A, and ISI were correlated with the ODI at the same time points (both at baseline and follow-up). A greater severity on the HADS-D, an older age, and associated leg symptoms at baseline were independently associated with a greater ODI at follow-up. A greater severity on the HADS-A and fewer educational years at baseline were independently associated with a longer TMOD. The associations of the HADS-D and HADS-A at baseline with disability at follow-up were greater than that of the ISI at baseline, based on the regression models. CONCLUSION: Greater severities of depression and anxiety at baseline were significantly associated with greater disability at the five-year follow-up point. The associations of depression and anxiety at baseline with disability at the long-term follow-up point might be greater than that of insomnia at baseline.