Assessing the impact of the early COVID-19 era on antibiotic-resistant threats in inpatient settings: A mixed Poisson regression approach

BACKGROUND: During the COVID-19 pandemic, increased antibiotic prescribing and infection prevention challenges coincided with antibiotic-resistant (AR) infection increases. Clostridioides difficile (C difficile) and methicillin-resistant Staphylococcus aureus (MRSA) are serious, costly AR threats. Health inequities in pandemic-era AR infections are not well-characterized. METHODS: North Carolina statewide inpatient admissions were used to determine monthly admission rates and admission rate ratios (RRs) for C difficile and MRSA infections comparing 2017-2019 (prepandemic) to 2020 (pandemic exposure) using mixed-model Poisson regression adjusted for age, sex, comorbidities, and COVID-19. We assessed effect measure modification by admissions’ community-level income, county rurality, and race and ethnicity. Mean total costs by infection type were compared. RESULTS: With pandemic exposure, C difficile (adjusted RR = 0.90 [95% confidence interval [CI] 0.86, 0.94]) and MRSA pneumonia (adjusted RR = 0.97 [95% CI 0.91, 1.05]) decreased, while MRSA septicemia (adjusted RR = 1.13 [95% CI 1.07, 1.19]) increased. Effect measure modification was not detected. C difficile or MRSA coinfection nearly doubled mean costs among COVID-19 admissions. CONCLUSIONS: Despite decreases in C difficile and most MRSA infections, the early COVID-19 pandemic period saw continued increases in MRSA septicemia admissions in North Carolina. Equitable interventions to curb increases and reduce health care costs should be developed.