Introduction: Autoimmune gastrointestinal dysmotility (AGID) is a consequence of autoimmune autonomic neuropathy and is a known cause of gastroparesis. The diagnosis of AGID-associated gastroparesis (AGID-G) often includes the identification of a neuronal autoantibody in the presence of dysautonomia and gastroparesis (seropositive disease). However, there is growing awareness of seronegative AGID-G. The aim of this study is to explore differences in clinical presentation and response to treatment between seronegative and seropositive AGID-G patients.
Methods: A retrospective study was conducted of 2,729 adult patients who underwent paraneoplastic/neuronal antibody testing. Within this cohort, patients with gastroparesis were identified based on >10% retention of test meal at 4 hours during egg-toast meal gastric emptying study (GES). A diagnosis of AGID-G was confirmed by GI and/or neurology clinical documentation. Fischer’s exact test and t-test were used. A p-value of ≤ 0.05 was considered statistically significant.
Results: Of 2,729 adult patients who underwent autoantibody testing at a tertiary care center, 172 (6.3%) patients had gastroparesis. Of the 172 patients, 20 had seropositive AGID-G and 20 had seronegative AGID-G (Table 1). Seronegative AGID-G patients were more likely to require nutritional support (PEG-J or TPN) compared to seropositive patients (55.0% vs. 20%, p = 0.048) (Table 1). Notably, seronegative patients were more likely to fail PEG-J feeding and require TPN compared to seropositive patients (40% vs. 5%, p = 0.02). There were no statistically significant differences regarding age at gastroparesis diagnosis, gender, % retained at 4 hours during GES, immunosuppressive treatments tried, or response to immunosuppressive treatments . There was no clear trend regarding specific antibodies within the seropositive AGID-G cohort.
Discussion: Seronegative AGID-G patients were more likely to require nutritional support with either PEG-J enteral feeding or TPN, despite other clinical factors being similar. These results support: 1) a more severe disease course or more severe symptomatology for the seronegative phenotype or 2) treatment delay in seronegative disease until later in disease course when nutritional support is needed. Both possibilities have significant clinical implications and need to be investigated further. Providers need to be aware and vigilant of seronegative AGID-G, and this study provides evidence the approach to seronegative AGID-G may need to be revised.
