Sex-Related Differences in the Diagnosis and Evolution of Parietal Cell Antibody-Positive Autoimmune Gastritis: A Large Single-Center Retrospective Cohort Study

Background/Objectives: Autoimmune gastritis (AIG) is more common in females, although studies assessing the differences between females and males are scarce. Therefore, this retrospective observational study aimed to assess differences at diagnosis and the evolution of the full spectrum of AIG between females and males. Methods: A large retrospective single-center cohort study was performed. Two cohorts were included: patients newly diagnosed with AIG with positive parietal cell antibodies between June 2013 and June 2023, and those who underwent at least one follow-up endoscopy, constituted the second cohort. Both cohorts were categorized by sex. Results: A total of four hundred twenty-six patients were included. Three hundred seventeen were females (74.4%) and 109 males, with a median age of 53.5 years (IQR 44.7–65.3). Females were more likely to be non-smokers (71.5%, 226 patients versus 57.8%, 63 patients; p = 0.01), higher prevalence of autoimmune hypothyroidism (72 females, 22.7% versus nine males, 8.3%; p = 0.001), dyspepsia (130 individuals, 41% versus 28 individuals, 25.7%; p = 0.004), and iron deficiency anemia (100 females, 31.6% versus 18 males, 16.5%; p = 0.002), while vitamin B12 deficiency was higher amongst males (22, 21.6% versus 36; 11.6%; p = 0.012). Histological and endoscopic stages were similar at the diagnosis. The logistic regression identified iron deficiency anemia (OR 2.9; 95% CI 1.47–5.72; p = 0.002), dyspepsia (OR 2.3; 95% CI 1.28–3.9; p = 0.005), lower ferritin levels (OR 0.99; 95% CI 0.98–0.99; p < 0.001), and autoimmune hypothyroidism (OR 2.7; 95% CI 1.24–5.8, p = 0.012) associated with females at diagnosis. No significant differences were observed regarding progression to a worse stage (47 females, 39.1% versus 9 males, 28.1%; p = 0.26). Conclusions: In conclusion, this large retrospective study showed some differences in clinical factors associated with AIG, although the evolution was similar. Clinicians should be particularly vigilant for the diagnosis of AIG in female patients with iron deficiency anemia, dyspeptic symptoms, and autoimmune hypothyroidism.