Change in self-reported activity in chronic low back pain after 13 years – a prospective longitudinal cohort study in primary healthcare

Background The knowledge about the improvement of body function, activity and participation in chronic low back pain (CLBP) over a period of over ten years is still insufficient. The study aimed to investigate the long-term change for body function, self-reported activity due to CLBP e.g. Roland Morris Disability Questionnaire (RMDQ) and work participation. Methods A 13-year prospective longitudinal cohort study of women with CLBP seeking primary healthcare. Women ( n = 130) with CLBP (> 12 weeks) were included in 2004 to 2005 (baseline), after two and 13 years. The assessment included questions about socio-demographic data, comorbidity, and pharmacological treatment, physical capacity-tests, and patient reported outcome questionnaires. Changes in measurements, for physical capacity, pain intensity, pain localisations, RMDQ, symtoms of anxiety and depression, clinical stress symptoms, and health-related quality of life, between baseline and the 13-year follow-up were calculated. Depending on the data level and distribution, either parametric or non-parametric tests were applied. A mixed effect model was used to analyse repeated measures of RMDQ from baseline to the two-year and 13-year follow-ups, comparing the group with localised CLBP and CLBP + widespread pain (WP) group. The RMDQ was dependent variable and age, education level, pain intensity, 6-Minute Walk Test, symptoms of stress, and depression were included as confounding factors. Results 67% (87/130) could be followed up after 13 years. 26% of the participants (22/86) fulfilled the criteria for WP at baseline. All measurements showed small improvements or were stable, except for hand grip strength. The mean change in RMDQ was − 3.3 (4.1) points. 73% (63/86) improved at least one point and 40% (34/86) improved ≥ 5 points on RMDQ from baseline. RMDQ improved in both the groups CLBP and CLBP + WP over the 13-year period ( p < 0.001) when adjusting for age, education, pain intensity, 6-Minute Walk Test, symptoms of stress, and depression. Conclusions All outcome measurements, except for hand grip force either showed small improvements or remained stable over a period of 13 years. For activity related to CLBP, no differences were found between the CLBP group and the CLBP + WP group when adjusting for pain intensity, physical capacity, stress, and depression. 40% improved with clinical important change in self-reported activity related to CLBP over a period of 13-years, which is important information to provide to individuals seeking primary healthcare for CLBP. Trial registration ClinicalTrials.gov, ID: NCT03974191. Registration date: 27 May 2019.