It is well known that antimicrobial resistance (AMR) creates a substantial and ongoing public health and economic burden and understanding the size and nature of this burden is important for the ability to respond to the threat of AMR. However, estimating or projecting that burden within the U.S. is a difficult task that prompts a variety of assumptions and produces conflicting results, making it challenging for researchers and policymakers to interpret and act upon that data.
To better understand the issues that complicate efforts to model the current and future AMR burden in the U.S., we conducted a systematic literature review of the 15 combinations of pathogen and drug resistance, nearly all of which were designated serious or urgent threats by CDC in its report Antibiotic Resistance Threats in the United States, 2019 (CDC, 2019). Our primary objective was to assess the availability and quality of published studies on the 15 selected pathogen-drug combinations that could support models of the AMR burden in the U.S. In so doing, we defined the key model parameters as mortality, length of stay (LOS), and healthcare costs for resistant and susceptible infections of interest and characterized the current state of the literature on those parameters.
In general, we found insufficient data in the literature to support infection-site-specific AMR burden modeling. This poses a major obstacle, as mortality and LOS vary widely across infection sites. For example, BSIs make up the vast majority of included studies yet are associated with substantially higher mortality rates than other infection types. Accordingly, building a burden model exclusively on these relatively abundant studies would lead to overestimation. However, even differentiating between just four infection sites (BSIs, UTIs, SSIs, and pneumonia) is not feasible based on the studies we included.