Spondyloarthropathy in Inflammatory Bowel Disease: From Pathophysiology to Pharmacological Targets

The management of patients with inflammatory bowel disease-associated spondyloarthritis: Italian Group for the Study of Inflammatory Bowel Disease (IG-IBD) and Italian Society of Rheumatology (SIR) recommendations based on a pseudo-Delphi consensus

Spondyloarthritis (SpA) is the most frequent extraintestinal manifestation in patients with inflammatory bowel diseases (IBD). When IBD and spondyloarthritis coexist, musculoskeletal and intestinal disease features should be considered when planning a therapeutic strategy. Treatment options for IBD and SpA have expanded enormously over the last few years, but randomized controlled trials with specific endpoints focused on SpA are not available in the IBD setting. To address this important clinical topic, the Italian Group for the Study of Inflammatory Bowel Disease (IG-IBD) and the Italian Society of Rheumatology (SIR) jointly planned to draw updated therapeutic recommendations for IBD-associated SpA using a pseudo-Delphi method. This document presents the official recommendations of IG-IBD and SIR on the management of IBD-associated SpA in the form of 34 statements and 4 therapeutic algorithms. It is intended to be a reference guide for gastroenterologists and rheumatologists dealing with IBD-associated SpA.

Mendelian randomization analysis reveals causal associations of inflammatory bowel disease with Spondylarthritis

OBJECTIVE

Inflammatory bowel disease (IBD) is strongly associated with Spondylarthritis (SpA), but the causal relationship remains unclear. This study explores the causal associations between IBD (Crohn's disease [CD] and ulcerative colitis [UC]) and several common subtypes of SpA (Ankylosing Spondylitis [AS], Psoriatic Arthritis [PsA], and Reactive Arthritis [ReA]), using bidirectional two-sample Mendelian randomization (TSMR).

METHODS

The causal effects of genetically predicted IBD on AS, PsA, and ReA were firstly investigated in this forward study. The causal effects from AS, PsA, and ReA on IBD were analyzed in the reverse MR. Inverse variance weighted, weighted median, and MR-Egger were applied in the MR analyses. The pleiotropic effects, heterogeneity, and leave-one-out sensitivity analysis were also evaluated.

RESULTS

The forward MR analysis demonstrated that IBD increased risk for AS (OR:1.278; P = 1.273 × 10-5), PsA (OR:1.192; P = 1.690 × 10-5), and ReA (OR:1.106; P = 1.524 × 10-3). Among them, CD increased risk of AS (OR:1.196; P = 3.424 × 10-4), PsA (OR:1.101; P = 1.537 × 10-3), ReA (OR:1.079; P = 6.321 × 10-3) whereas UC increased risk of AS (OR:1.166; P = 2.727 × 10-2), PsA (OR:1.110; P = 1.944 × 10-2), and ReA (OR:1.091; P = 1.768 × 10-2). The reverse-direction MR disclosed no notable association; neither was any evidence of pleiotropy detected.

CONCLUSION

Our study verifies a causal effect of IBD to AS, PsA as well as ReA, but not vice versa. This might bring new insights for the management of IBD and SpA in clinical practice.