Autoimmune Metaplastic Atrophic Gastritis (AMAG): Regional Demographics and Their Effect on Prevalence

Autoimmune metaplastic atrophic gastritis (AMAG) is a chronic immune-mediated form of gastritis characterized by damage to oxyntic cells, ultimately resulting in both iron deficiency with or without anemia and pernicious anemia. The current dogma is that AMAG is a disease of White Northern European women of advanced age. We, therefore, sought to examine the prevalence of AMAG in biopsies obtained from populations enriched for self-identified Hispanics for cross-comparison against data from previously reported populations enriched for self-identified White, non-Hispanic patients. To that end, we prospectively collected 1708 sequential gastric biopsies performed at the University of Miami Hospitals/Jackson Health Systems clinics from 1692 patients over a 1-year period as well as pertinent clinical parameters. These Florida data were then compared against data previously collected from the Baltimore population, which has far lower numbers of Hispanic patients. Self-identified race and/or ethnicity were used. From these 1692 patients, we identified 79 patients (4.6%) with AMAG. These included 60 women (76%) and 19 men (24%), with a F:M ratio of 3.1:1. Patients had a median age of 60 years (range: 15-83). Self-identified race and/or ethnicity were: 60 (76.0%) Hispanic, 9 (11.4%) Black, 9 (11.4%) White, and 1 Asian (1.2%). The median age at initial presentation was: 51 years (range: 15-83) in Hispanics, 77.2 years (range: 46-74) in Blacks, 59 years (range: 49-79) in Whites, and 58 years in the only Asian patient. The overall demographics of AMAG largely mirrored the Florida population, with an over-representation of Hispanics (Florida inhabitants self-report as 70% Hispanic). The overall 4.6% prevalence of AMAG in the Florida population differed significantly from the 1.1% in Baltimore (p < .00001), a finding that presumably reflects the large Hispanic population. In fact, the prevalence of AMAG is far higher in Hispanic patients. Awareness of these data should increase recognition of AMAG in this population.