Prevalence and clinical correlates of antinuclear antibody in patients with gastroparesis

Background: Autoimmunity may play a role in the pathogenesis of gastroparesis in a subset of patients. Antinuclear antibody (ANA) testing is often used to screen for autoimmune disorders. Aims: 1) Determine prevalence of a positive ANA in patients with gastroparesis; 2) Describe characteristics of idiopathic gastroparesis patients with positive ANA. Methods: Patients were assessed with gastric emptying scintigraphy (GES), symptom assessment via Patient Assessment of Upper GI Symptoms [PAGI-SYM], and blood tests—ANA, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP). Results: Positive ANA was seen in 148 of 893 (17%) patients with gastroparesis, being similar in idiopathic (16% of 536 patients), T1DM (16% of 162), T2DM (18% of 147), and postfundoplication (19% of 48 patients) gastroparesis. Among 536 patients with idiopathic gastroparesis, ANA titer 1:40–1:80 was seen in 33 (6%) patients, 1:160–1:320 in 36 (7%) patients, and ≥1:640 in 17 (3%) patients. Increasing ANA titer was associated with female gender (p = 0.05), Hispanic ethnicity (p = 0.02), comorbid rheumatoid arthritis (p = 0.02), systemic sclerosis (p = 0.004), and elevated ESR (p = 0.007). ANA positivity was associated with lower total GCSI (p = 0.007) and lower nausea/vomiting subscale (p = 0.0005), but not related to gastric emptying. Conclusions: The prevalence of a positive ANA in patients with gastroparesis was high at ~17% and did not differ significantly based on etiology. In idiopathic patients, ANA positivity was associated with rheumatoid arthritis, systemic sclerosis, and elevated ESR. ANA-positive gastroparesis represents a subset who often have other autoimmune symptoms or disorders, but less severe nausea and vomiting.