Time course and risk factors of evolution from potential to overt autoimmune gastritis

Background: The natural history of patients with potential autoimmune gastritis (AIG), defined by the presence of serum anti-parietal cell antibody (PCA) positivity and no gastric histopathological alterations, is unknown. We therefore aimed to assess the natural history and clinical correlates of potential autoimmune gastritis (AIG). Methods: In 2000–2019, we enrolled potential AIG patients by monitoring once a year (±6 months) histopathological evolution into overt AIG, defined as the occurrence of atrophy in the oxyntic mucosa. Factors affecting disease progression were assessed. Results: Fifty-one potential AIG patients (median age 57 years, IQR 43–73, F:M ratio 1.7:1) were monitored for up to 15 years (median 6 years, IQR 3–8). Of them, 24 (47.1%) evolved into overt AIG in a median time of 2 years (IQR 2–4.5). Having a concomitant autoimmune disorder (HR 4.09, 95% CI 1.52–11.00; p = 0.005), but not older age (HR 1.00, 95% CI 0.45–2.22; p = 0.992) and female sex (HR 1.19, 95% CI 0.51–2.78; p = 0.395), was associated with evolution into overt AIG. Conclusions: Roughly one in two potential AIG patients will evolve into overt AIG over a median time of two years, especially those with a concurrent autoimmune disorder.