Abstract A107: Disparities in gastric adenocarcinoma and its precursors in South Texas: A secondary analysis of electronic health data from two affiliated institutions
Authors: Parma Dorothy A Long , Moffett Eric , Morales Ariel , Ramirez Amelie G 
Published: September 2020

Abstract
Gastric (GC) affects U.S. Latinos disproportionately relative to non-Hispanic whites (NHWs), particularly in South Texas (STX). Helicobacter pylori infection (HP) accounts for 90% of cases and is considered the primary GC risk factor. Disparities in GC incidence rates are likely linked to similar disparities in diagnosis and management of precursor conditions, including chronic HP, gastric ulcer (GU) and atrophic gastritis (AG). Preliminary studies found significantly higher HP exposure among Latinos than NHWs in two local populations: 30.3% vs. 9.2% in men participating in a prostate cancer cohort, and 36.7% vs. 16.2% among men and women attending UT Health San Antonio (UTMed) clinics. This study aimed to establish differences in H. pylori-related gastric diagnoses among Latino and NHW patients at UTMed and its affiliated hospital University Health System (UHS). Aggregate data was compiled from a PCORnet CDM data set created from electronic health records sourced from the two health systems and stored at the Clinical Informatics Research Division in the Department of Population Health Sciences at UTMed. Data was selected by using cohort demographic criteria and standard codes (ICD9/10 and LOINC) for diagnostic and laboratory criteria. DBVisualizer Pro was used to write an Oracle SQL script. Results were exported into Microsoft Excel and the file transferred securely via REDCap Send-It. Incidence rate ratios (RR) for all diagnoses were analyzed using STATA. A total of 844,414 records, 54.5% of which were women, were found matching the criteria (age 18 or older, Latino and NHW; Blacks and Asians excluded). These were examined for H. pylori (HP) infection with or without the other GC precursor conditions, as well as gastric adenocarcinoma (GCA), the most common form of GC. Results were stratified by age, gender, ethnicity and health system. Women accounted for most of the diagnoses (67-72%), except for GU at UHS and GCA at both locations. There were no differences in diagnosis rates between health systems, except for GU (Latino UHS patients were 1.49-1.77 times at risk as their UTMed counterparts) and HP (NHW UTMed women were 1.34 times at risk as UHS women). Latinos had higher rates of all diagnoses (p&lt;0.05) except for GU, where there was no difference between ethnic groups and locations. The largest overall disparity was for combined HP+GCA at UHS (RR=3.50; 95% CI 1.37, 10.60; p=0.0037). Latina women largely accounted for this (6.00; 1.34, 55.20; p=0.0074). UHS GCA was the single diagnosis with the greatest disparity (1.81; 1.47, 2.23; p&lt;0.001), followed by UHS HP (1.75; 1.66, 1.85; p&lt;0.001). Latina women were twice as likely to have GCA as their NHW counterparts at both health systems (1.87-2.12; 1.34, 3.02; p&lt;0.001). Subsequent analyses will take into consideration management practices, follow-up and covariates like median income and geographic disparities, as well as incidence rates of gastric lymphomas, including mucosa-associated lymphoid tissue (MALT), the only lymphoma associated with HP.
Citation Format: Dorothy A Long Parma, Eric Moffett, Ariel Morales, Amelie G Ramirez. Disparities in gastric adenocarcinoma and its precursors in South Texas: A secondary analysis of electronic health data from two affiliated institutions [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr A107.