Gastrointestinal involvement in dermatomyositis: multicentric retrospective cohort study

Gastrointestinal (GI) involvement in myositis is a severe extra muscular manifestation with potentially life-threatening outcomes. However, it remains poorly characterized. We aimed to evaluate the prevalence of GI involvement in DM and to describe its characteristics in anti-nuclear matrix protein-2 (NXP2) DM.

The prevalence of GI involvement across DM subgroups was assessed in a retrospective monocentric DM cohort (n = 119). It was further investigated in a retrospective multicentric cohort of anti-NXP2 DM (n = 48). GI involvement (defined as any symptomatic GI lesion, excluding isolated dysphagia) was considered severe when requiring surgery and/or intensive care unit admission.

In the monocentric DM cohort, severe GI involvement was observed in 18% of anti-NXP2 patients and 6% of anti-melanoma differentiation-associated protein 5 (MDA5) patients. Severe GI involvement was significantly more frequent in anti-NXP2 patients compared with other DM subgroups [hazard ratio 8.85 (95% CI 1.62-48.35)]. In the multicentric anti-NXP2 cohort, severe GI involvement (including four digestive perforations and three digestive haemorrhages) occurred in 12.5% of patients. Anti-NXP2 patients with severe GI involvement were significantly younger (median age 24.5 vs 42.5 years; P < 0.01) and more frequently presented with facial oedema at diagnosis (83% vs 33%; P = 0.03). At the time of GI involvement, 78% of anti-NXP2 patients had concomitant skin and/or muscle disease activity. No deaths were reported.

Severe GI involvement represents a life-threatening complication in DM and is mainly associated with anti-NXP2 antibody. In anti-NXP2 DM, young age and facial oedema are associated with severe GI involvement.