Evaluating Variation in Resistant Gram-Negative Infections and Antibiotic Treatment

Significance to VA: Antimicrobial resistant (AR) bacterial infections are a significant cause of morbidity and mortality in Veterans every year. Gram-negative infections cause over 100,000 infections or colonization/year in the VA. Veterans have many of the common risk factors associated with multidrug-resistant gram negative- organisms (MDRGNOs) including multiple comorbidities and prior exposure to antibiotics, long lengths of stay before infection, and use of invasive devices. More evidence is identifying variation in burden of infections and AR by race and ethnicity. However, limited data exist that have identified the drivers of these inequities (e.g. individual and structural factors (social determinants of health (SDOH), racism)) and their impacts on health outcomes; and no data is available in the Veteran population. In addition, treatment options for AR infections are limited due to few effective drugs. Limited treatment options could not only result in poor outcomes after infection, but also potentially result in more inequity where certain patients do not get prescribed the recommended most effective novel treatments, or are newly FDA approved and, thus, more costly. Variation in equitable access to medications are well documented in the Veteran population. However, there is a critical information gap for identifying drivers of inequity in prescribing for AR infections, understanding Veteran perspectives related to MDRGNO management, and identifying targets for intervention to ultimately achieve pharmacoequity in the VA system of care. This project is significant because disparities in MDRGNOs and prescribing have not been rigorously evaluated. Innovation and Impact: This project leverages robust VA data with patient variables, microbiology data, and antibiotics prescribed not readily available in any other large, national, integrated health system data source. This project will have impact as we will use the findings of this study for future next steps to develop system- level strategies to standardize and implement equitable care across the VA’s large patient population with complex, chronic conditions who remain at the highest risk of MDRGNOs. Specific Aims: Aim 1: Evaluate variation in the burden of MDRGNOs by race, ethnicity and SDOH and identify drivers of disparities. H1: AR will be higher in patients from minoritized groups, vary by geographic location, and be driven by social factors. Aim 2: Assess equity in prescribing of antibiotics to treat MDRGNOs and their association with patient outcomes. H2: Prescription of antibiotics newly FDA approved, in shortage, or guideline concordant for Carbapenem-resistant Enterobacterales, Carbapenem-resistant Acinetobacter baumannii, extended-spectrum beta-lactamase, and multidrug-resistant P. aeruginosa will vary by race, ethnicity, VA priority status, and SDOH. Aim 3: Identify clinician strategies and recommendations for equity in antibiotic prescribing for MDRGNOs and assess patient experiences with MDRGNOs and prescribing. Methodology: An adaptation of the Andersen and Newman model on access to care will be used to conduct a study to examine factors associated with variation in MDRGNO burden and equitable access to antibiotics. Using VA microbiology and encounter data we will define cohorts of Veterans with Enterobacterales, P. aeruginosa, or A. baumannii infections and assess differences in prevalence of AR, and drivers of disparities adjusted for clinical factors. Logistic regression will assess differences in antibiotics prescribed -/+7 days from the MDRGNO culture date by race, ethnicity, and SDOH and outcomes. A qualitative study will elucidate the clinical decision-making process for antibiotic prescribing for MDRGNOs and patient experiences to identify actionable strategies and recommendations to ensure equitable access to antibiotics for MDRGNOs. Path to Translation/Implementation: We will use the data from this study to inform the development of system- leve Project Number: 1I01RD000413-01A2 | Fiscal Year: 2026 | NIH Institute/Center: Veterans Affairs (VA) | Principal Investigator: CHARLESNIKA EVANS | Institution: EDWARD HINES JR VA HOSPITAL, HINES, IL | Activity Code: I01 | Study Section: HSR-2 Behavioral, Social, and Cultural Drivers of Health and Care[HSR2] View on NIH RePORTER: https://reporter.nih.gov/project-details/11241018