Interrelationship Between Depression and Disease Activity in Rheumatoid Arthritis: A Systematic Review and Meta-analysis Using HADS, PHQ-9, BDI, CES-D, SDS, and DAS28 Tools

INTRODUCTION: Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by inflammation and progressive destruction of cartilage and bones. In the world, RA affects 0.2-1.2% of the population, and the highest percentage of those affected is women. Depression has been identified as a comorbid condition of RA. This condition tends to increase pain as well as the intensity of RA. The objective of this study is to systematically analyse the prevalence rates, risk factors, and effects of depression among RA patients and establish the knowledge gaps that should inform improved comprehensive management. METHODS: This systematic review adhered to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) protocol. Electronic databases PubMed, Google Scholar, and Scopus database from 2015 to 2025. Cross-sectional studies involving adults aged 18 years and above diagnosed with rheumatoid arthritis (RA) and assessed using validated measures of depression. Data analysis of the results was performed using SPSS version 26.0. A forest plot was generated through meta-analysis to calculate the pooled prevalence within the study population. Heterogeneity among studies was examined using the I2 statistic and the Cochran's Q test. The protocol for this systematic review and meta-analysis was registered with PROSPERO (International Prospective Register of Systematic Reviews) with registration no. CRD420261287407. RESULTS: Out of 9,950 initially identified records, only 19 studies were included. The pooled prevalence of depression was high and varied depending on the diagnostic instrument used and the age group considered. The highest prevalence was observed among the subjects aged 50-60 years. Higher detection rates were reported with the Hospital Anxiety and Depression Scale (HADS) and the Patient Health Questionnaire -9 (PHQ-9). Depression was found to be associated with greater disease activity, fatigue, pain, lower quality of life, and treatment non-adherence. DISCUSSION: This meta-analysis highlights that depression is a highly prevalent comorbid condition among RA patients, with a pooled prevalence of 39.31%. Substantial heterogeneity across studies (I2 = 96.9%) suggests that variation exists in diagnostic tools, population characteristics, and regional contexts. Higher prevalence rates were observed in Middle Eastern and South Asian populations; this might be influenced by socioeconomic factors, healthcare accessibility, and cultural stigma in mental health reporting. CONCLUSION: Depression has been found to have a high prevalence among RA patients across diverse populations. The interpretation is limited by the inclusion of cross-sectional studies and high heterogeneity. The findings support the routine depression screening and management in RA patients. Future research should investigate the development of RA in depression patients to understand the possible bidirectional relationship.