Infectious Disease Alert Updates
April 1, 2024
Reprints
By Carol A. Kemper, MD, FIDSA
Medical Director, Infection Prevention, El Camino Hospital, Palo Alto Medical Foundation
The Gut Biome and Social Determinants of Health: A Factor in C. diff Infection?
SOURCE: Reveles KR, Strey KA, Abdul-Mutakabbir JC, et al. Infectious inequity: How the gut microbiome and social determinants of health may contribute to Clostridioides difficile infection among racial and ethnic minorities. Clin Infect Dis 2023;77(Suppl 6):S455-S462.
At a recent hospital quality council meeting, it was recommended our infection prevention team present data for health equity for hospital-acquired infections (HAIs), describing the proportion of HAIs based on ethnicity/race. Interestingly, the data team found the opposite of what was anticipated. While some report a higher rate of HAI in vulnerable communities, the proportion of patients with HAI who were Caucasian at our facility was higher than the percentage of Caucasians in the community (57% vs. 48%). The risk of HAI was lower in Asian people (17%), Hispanic/Latino people (7.8%), and Black people (0.34%) than the proportions of those groups in the local population (33%, 18%, and 1.6%, respectively). Was this an accurate reflection of risks at our facility? It seems that before defining health equity — or inequity, which is really the point of these data analytics — it is important to know what you are comparing.
In contrast to our small data set, others have observed an increased risk of Clostridioides difficile infection (CDI) and associated mortality in vulnerable communities. These authors present their ideas about how social determinants of health and gut biome dysbiosis might contribute to the increased risk for CDI and morbidity. First, infection, in general, is the second leading contributor to racial disparity in all-cause mortality, even compared with cancer and cardiovascular risk. However, infections that disproportionately affect vulnerable communities, including human immunodeficiency virus (HIV), viral hepatitis, sexually transmitted disease, and tuberculosis, would not obviously appear to directly result in an increased risk of CDI. Most cases of CDI (75%) are associated with hospitalizations and prolonged use of antibacterials. However, 20% to 27% of CDI cases are not specifically associated with a healthcare facility. Even after controlling for antibiotic use, the prevalence and mortality of CDI in Hispanic/Latino people and Black people is reportedly greater. So why do Black or Hispanic/Latino patients have a disproportionate rate of CDI, longer hospital stays, higher rates of recurrence, and worse outcomes?
In addition to the obvious socioeconomic disparities, such as lack of insurance, the use of emergency rooms for basic health services, and increased treatment costs out of pocket, the authors speculate that other determinants of poverty and health may affect the fecal biome and dysbiosis in undetermined ways. Factors such as diet, stress, alcohol use, obesity, personal hygiene, and other factors affecting the personal environment may have negative effects on the gut biome. Certain foods (e.g., high in fat and low in fiber) negatively affect the gut biome. Therefore, poorer diet may contribute to functional changes in gut flora that could play a role in acquisition of C. difficile and risk of active CDI.
As I read through this article, I really wanted to know whether the rate of C. difficile colonization is greater in certain vulnerable groups. Is dependence on fast food restaurants a factor? Since 44% of foodborne outbreaks occur from restaurants compared with 24% from food prepared at home, could the risk of exposure to CD be greater in those who depend on fast food for their nutrition? Is the quality of meat an issue, since some data suggest that ground meat may be at greater risk for colonization with C. difficile bacteria? Therefore, if lower income people depend more on ground meat products than more expensive cuts of meat, are they at greater risk for C. difficile exposure?
We know from the COVID pandemic that certain groups disproportionately fill many of the lower paid healthcare positions. Could this result in a greater risk of workplace exposure to C. difficile? On the other hand, other data indicate that CDI may be less frequent and less severe in those with prior colonization/exposure, such as healthcare workers, so maybe prior colonization is a good thing (as long as you avoid antibiotics at the time). And I would imagine that renal dysfunction, diabetes, and other factors that affect immune system integrity and ability to clear CDI would be significant factors.
The authors suggested that future research into the disproportionate risk of CDI morbidity and mortality in vulnerable populations integrate socioeconomic determinants of health, particularly as they affect the gut microbiome. Clearly, a broader understanding of environmental and health factors is needed to better understand this observation in vulnerable communities. An interesting observation is the low rate of CDI in patients with recognized colonization at our facility (~ 5%), thus, the majority of patients with positive perirectal screening tests (95%) do not develop active CDI during their hospital stay. In truth, we really do not understand why some people get active CDI and others do not.
Pre-Op Screening for SARS-CoV-2 Is Not Cost Effective
SOURCE: Uno S, Goto R, Honda K, et al. Cost-effectiveness of universal asymptomatic preoperative SARS-CoV-2 polymerase chain reaction screening: A cost-utility analysis. Clin Infect Dis 2024;78:57-64.
During the first two years of the COVID pandemic, many acute care facilities across the United States and in other countries relied on universal SARS-CoV-2 screening using polymerase chain reaction (PCR) testing for pre-operative screening of asymptomatic persons. The explicit benefit of this measure was to identify those individuals who were presently asymptomatic and positive but who may go on to develop symptomatic COVID infection and its complications, including respiratory failure and thromboembolic events. A lesser benefit was perhaps to reduce the risk of nosocomial transmission, although this benefit was dubious since the operating room staff were already appropriately masked and gowned, and the risk of nosocomial transmission from asymptomatic persons was unknown.
These Japanese authors constructed a decision tree model to assess the cost-effectiveness of routine pre-operative SARS-CoV-2 PCR screening of asymptomatic persons presenting for surgery, including estimates of an asymptomatic positive person presenting for surgery, the test positivity rate in the community, the cost of screening tests and delaying surgery, and the risk of COVID complications. The strategy included pre-operative screening two to three days prior to surgery vs. no screening. They estimated the test positivity rate of 0.07% and a screening cost of $7,600 USD. They established a cost-effectiveness threshold of 5 million Japanese yen per quality adjusted life year (QALY) (approximately $38,000 USD per QALY). Cost-effectiveness mainly depended on the test-positivity rate in the community and the risk of pulmonary complications.
Using these figures, the cost of averting one death was $566,000 USD (approximately $2.21 million USD per QALY). Even if the risk of developing pulmonary complications of COVID increased to 0.22, asymptomatic screening was never cost effective, regardless of the test positivity rate in the community or the risk of an asymptomatic COVID infection in those presenting for surgery.
These data were based on estimates of complications of infection with the initial strains of SARS-CoV-2 and before vaccination and treatment were available. Therefore, they are not likely to apply to newer strains.
An unknown “human factor” that could affect this analysis is the reassurance that both patients and surgical staff achieved from asymptomatic SARS-CoV-2 screening. At the time this strategy was employed, elective surgeries had been suspended, and many patients — and surgeons — were frightened about the risks of exposure in the hospital and the risks of exposure during surgery.
Universal screening brought patients back to the hospital for procedures — and it brought the surgical staff back into the operating rooms — generating much needed dollars to support acute care facilities at a time when budgets were stretched thin. Pre-operative SARS-CoV-2 screening might not have saved lives or made sense, but it saved many hospitals from going bankrupt.
The Gut Biome and Social Determinants of Health: A Factor in C. diff Infection?
Pre-Op Screening for SARS-CoV-2 Is Not Cost Effective
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