The relationship between pain and depression and anxiety in people with inflammatory arthritis: A systematic review

This PROSPERO-registered (CRD42023411823) systematic review synthesised literature on the associations between pain and depression/anxiety in inflammatory arthritis, including the direction of effect, relationship mediators, and treatment impacts.

Protocolised-database searches were conducted to May-2023 and studies assessing the associations between pain and depression/anxiety and/or impacts of depression/anxiety treatment on pain in people with rheumatoid arthritis/spondyloarthritis identified. Studies with mixed-populations, non-translatable non-English studies, case-reports/series/reviews/editorials, and abstracts/letters with insufficient-data were excluded. Vote-counting/meta-analysis synthesised single-time-point associations. Narrative synthesis summarised longitudinal associations/mediators/treatment effects. JBI critical-appraisal tools and the Grading of Recommendations, Assessment, Development and Evaluations approach evaluated risk-of-bias and strength-of-evidence.

Seventy-nine studies were included. A bidirectional relationship between pain and depression was observed. At single-time-points, pain was higher in those with depression (standardised mean difference [SMD]=0.69 [95%CI 0.54,0.84]; representing a moderate effect as per Cohen's criteria); linear regressions demonstrated moderate associations between pain (outcome) and depression (explanatory-variable) (SMD=0.65 [0.31,0.99]) and small associations between depression (outcome) and pain (explanatory-variable) (SMD=0.24 [0.03,0.45]). Longitudinal studies indicated greater pain with worse depression. Findings were mixed for anxiety. Linear regressions showed minimal associations between pain (outcome) and anxiety (explanatory-variable) (SMD=0.03 [0.001,0.05]) and moderate between anxiety (outcome) and pain (explanatory-variable) (SMD=0.55 [0.20,0.91]). Two longitudinal studies considered mediators (one suggesting "passive coping" in depression). Trials indicated anti-depressants reduced pain in people with comorbid-depression. Thirty-five percent of studies were at high, 34% moderate, and 30% low risk-of-bias; evidence was very low/low-quality.

A modest bidirectional association exists between pain and depression in inflammatory arthritis (based on very low-quality evidence), supporting biopsychosocial pain management.