The one-year clinical course of back-related disability and the prognostic value of comorbidity among older adults with back pain in primary care.

Back pain and comorbidity are common in older adults. Comorbidity is a promising prognostic factor for the clinical course of back-related disability, but confirmatory studies assessing its prognostic value are needed. Thus, the aims of this study were to describe the clinical course of back-related disability during 1-year follow-up in patients aged ≥55 years visiting primary care (general practitioner, physiotherapist, or chiropractor) with a new episode of back pain and assess the prognostic value of comorbidity on back-related disability during 1-year follow-up. A prospective cohort study was conducted, including 452 patients. The outcome measure was Roland-Morris Disability Questionnaire (RMDQ, range 0-24) measured at baseline and at 3-, 6-, and 12-month follow-up. The Self-Administered Comorbidity Questionnaire was used to assess comorbidity count (CC, range 0-15) and comorbidity burden (CB, range 0-45). The RMDQ scores improved from median (interquartile range) 9 (4-13) at baseline to 4 (1-9), 4 (0-9), and 3 (0-9) at 3, 6, and 12 months, respectively. Using linear mixed-effects models, we found that CC and CB were independently associated with RMDQ scores. A 1-point increase in CC was associated with an increase in RMDQ score of 0.76 points (95% confidence interval [0.48-1.04]) over the follow-up year, adjusted for known prognostic factors. A 1-point increase in CB was associated with an increased RMDQ score of 0.47 points (95% confidence interval [0.33-0.61]). In conclusion, the clinical course of back-related disability for older adults presenting in primary care was favorable, and increased comorbidity was an independent prognostic factor for increased disability levels.