Short and long term predictors of pain severity and interference in primary care patients with chronic musculoskeletal pain and depression

Abstract

Background: Chronic pain and depression are frequent comorbidities in primary care. Depression and other clinical, psychological and social factors influence the clinical course of chronic pain.Objective: To study the short and long-term predictive factors of severity and interference of chronic pain in primary care patients with chronic musculoskeletal pain and major depression.Methods: Longitudinal study of a cohort of 328 patients. The outcomes are severity and functional interference of pain (Brief Pain Inventory) measured at 3 and 12 months.Results: 83% participants were women; average age was 60.3 years (SD=10.2). In multivariate models, baseline pain intensity predicted pain intensity at 3 months (β= 0.48; 95% CI=0.30-0.67) and at 12 months (β=0.39; 95% CI=0.17-0.61). Also, pain >2 years of evolution predicted long term pain intensity (β=0.86; CI95%=0.05-1.66). Occupational status as active worker predicted lower intensity at 12 months (β=-0.78; CI95%=-1.53 ​​to -0.03). Baseline pain interference predicted interference at 3 and 12 months (β=0.25; 95%CI=0.09-0.41 and β=0.22; 95%CI=0.02-0.41, respectively). Pain >2 years predicted greater interference at 12 months (β=1.07; CI95%=0.24-1.89). Physical comorbidity (Duke Severity of Illness score) was associated with greater interference in the short term (β=0.02; CI95 %= 0.00-2.05). Occupational status as active worker predicted less interference throughout the follow-up (β=-0.72; CI95%=-1.34 to -0.11 and β=-0.95; CI95%=-1.70 to -0.21, at 3 and 12 months).With regard to the psychological variables, catastrophism (Pain Catastrophizing Scale) predicted greater pain intensity and interference at three months (β=0.35; 95% CI=0.03-0.68 and β=0.36; 95% CI =0.02-0.71), but not long term.Conclusion: In a sample of adults with chronic pain and depression, this primary care study has identified various prognostic factors that independently predict the intensity and functional interference of pain. These factors should be targeted for individualized interventions. Trial registration: ClinicalTrials.gov (NCT02605278), registered 16/11/2015.