The influence of comorbidities on outcomes for older people with back pain: BACE-D cohort study

Abstract

Background: Comorbidities are common in older people with back pain but little is known about the influence of comorbidities on outcomes. Objectives: To explore the influence of the most prevalent comorbidities, and the number of comorbidities, on short (at 3 months) and long-term (at 12 months) outcomes of back pain in older people. Methods: We analyzed data from the ‘Back Complaints in the Elders’ Dutch study cohort (BACE-D) and included participants aged >55 years. We used the modified Self-Administered Comorbidities Questionnaire (SCQ), the Numeric Rating Scale (NRS) and the Roland–Morris Disability Questionnaire (RMDQ) to assess the number of comorbidities, pain intensity and back-related physical functioning, respectively. We conducted separate linear regression models to analyze the association between comorbidities and outcomes including potential confounders of age, sex, body mass index, smoking and alcoholic drinking status, back pain history, and baseline NRS and RMDQ scores. Results: Our study included 669 participants with a mean age of 66.5 (SD 7.7) years of whom 394 were female. More comorbidities were positively associated with higher pain intensity (3-month regression coefficient (β) =0.27, 95% CI 0.14–0.39; 12-month β = 0.31, 95% CI 0.17–0.45) and worse physical functioning (3-month β = 0.54, 95% CI 0.31–0.77; 12-month β = 0.64, 95% CI 0.37–0.92). Four of the 5 commonest comorbidities were musculoskeletal problems. Older participants with musculoskeletal comorbidities had higher pain intensity (3-month β = 0.89 95% CI 0.41–1.37; 12-month β = 1.17, 95% CI 0.65–1.69), and worse physical functioning (3-month β = 1.61, 95% CI 0.71–2.52; 12-month β = 1.85, 95% CI 0.82–2.89, P-value < 0.001) compared to participants without musculoskeletal comorbidities. Conclusions: More comorbidities are associated with worse back pain outcomes in older adults. Participants with musculoskeletal comorbidities had worse back pain outcomes than those without.