Abstract
QUESTION: Collective evidence for the bidirectional association between depression and autoimmune diseases (ADs) is scarce, especially for subgroups of patients with specific ADs. We conducted a meta-analysis to determine the incidence rates and relative risks (RRs) of depression among patients with ADs, and vice versa. STUDY SELECTION AND ANALYSIS: PubMed, Embase, Web of Science, Ovid, PsycNet and Cochrane were searched up to 10 September 2024. Cohort studies evaluating longitudinal risks between ADs and depression were included. Incidence rates and RRs of depression among patients with ADs and vice versa were pooled. FINDINGS: The analysis included 47 studies, involving over 40.77 million participants. The pooled incidence rate of depression among patients with ADs was 6.71% (95% CI 5.10% to 8.77%), with an RR of 1.85 (95% CI 1.57 to 2.19), higher in patients aged over 45 (2.30; 95% CI 1.62 to 3.26) and females (1.88; 95% CI 1.61 to 2.20). Conversely, the pooled incidence rate of ADs among depression was 0.54% (95% CI 0.24% to 1.19%), with an RR of 1.84 (95% CI 1.10 to 3.09). The incidence rate and RRs also varied across subgroups with the highest incidence rate in the musculoskeletal system and connective tissue (1.36; 95% CI 0.50 to 3.63) and RR in the genitourinary system (2.23; 95% CI 1.98 to 2.51). CONCLUSIONS: This study identified a bidirectional association between depression and ADs, with higher RRs among patients aged over 45 and females. Especially higher risks were also found for specific types of ADs including endocrine, nutritional, and metabolic diseases, genitourinary system, and skin and subcutaneous tissue. PROSPERO REGISTRATION NUMBER: CRD42024541053.