Anorectal Dysfunction in Systemic Sclerosis: Clinical Phenotypes and Functional Patterns

OBJECTIVE: To characterize specific physiologic defects in anorectal dysfunction in systemic sclerosis (SSc) using anorectal manometry (ARM), evaluate associations with gastrointestinal (GI) and extraintestinal clinical phenotypes, and explore potential serologic markers for risk stratification. METHODS: This retrospective cohort study included 50 patients with SSc from the Johns Hopkins Scleroderma Center Research Registry who underwent ARM between 2011 and 2022. Clinical, serologic, and ARM data were abstracted and analyzed. GI symptom burden was assessed using the UCLA SCTC GIT 2.0 instrument. ARM parameters included resting and squeeze pressures, rectal and urge sensations, and rectoanal inhibitory reflex (RAIR). Associations between ARM findings, autoantibody profiles, and clinical phenotypes were evaluated. RESULTS: Fecal incontinence was the most common indication for ARM (56%), followed by constipation (34%). ARM abnormalities were prevalent: 60% had hypotensive resting pressures, 24% had reduced anal squeeze, 31% had diminished rectal sensation, and 92% had abnormal RAIR. Patients with hypotensive resting pressures had longer disease duration (median 25 vs. 9 years, p=0.003) and higher FVC (88% vs. 75% predicted, p=0.018). Dual anti-centromere and Ro52 antibody positivity significantly associated with hypotensive resting pressures (100% vs. 56%, p=0.030). CONCLUSIONS: Anorectal dysfunction is common in SSc and may reflect underlying neuromuscular involvement. ARM abnormalities are associated with longer disease duration and specific autoantibody profiles, particularly anti-centromere and Ro52. Absent RAIR may serve as a distinguishing feature of SSc-related anorectal dysfunction. These findings support a neurogenic pathophysiologic mechanism and highlight the need for prospective studies to further define SSc disease progression and guide risk stratification.