Social Determinants Shape Who Gets Dangerous Hospital Infections, Review Finds

Healthcare-associated infections are often framed as a matter of clinical protocol: hand hygiene compliance, catheter insertion checklists, antimicrobial stewardship. A new systematic review suggests that framing is incomplete. The analysis, published in BMC Infectious Diseases by Chandni Shahdev of the University of Massachusetts Lowell, synthesizes a decade of U.S. evidence showing that the social circumstances patients carry into the hospital—insurance status, income, neighborhood deprivation, and race or ethnicity—are consistently linked to their risk of acquiring some of medicine’s most feared infections, and to how those infections play out afterward.

The stakes are enormous. According to figures cited in the review, an estimated 687,000 healthcare-associated infections occur in North America each year, contributing to nearly 72,000 deaths. These infections include methicillin-resistant Staphylococcus aureus (MRSA), Clostridioides difficile infection (CDI), catheter-associated urinary tract infections, central line-associated bloodstream infections, ventilator-associated pneumonia, and surgical site infections. Each is considered largely preventable with rigorous infection control, which is precisely why the review’s central finding—that the burden of these infections is not evenly distributed—has implications for how surveillance and prevention programs are designed.

Shahdev followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, searching PubMed, MEDLINE, and CINAHL for studies published between 2014 and 2024. The search combined HAI-specific terms with social determinants of health keywords including race, income, insurance status, poverty, and area deprivation. Eligible studies had to be conducted in the United States or Canada and to examine at least one healthcare-associated infection alongside at least one social determinant. From 3,068 records screened, 21 studies met the inclusion criteria—a narrow yield that itself tells a story about how rarely infection research has been designed to interrogate social inequity.

One of the starkest findings is geographic in scope: every single included study was based in the United States. No Canadian research met the final eligibility criteria, despite the review’s original ambition to cover North America. That absence means the evidence base for how social factors shape infection risk in a country with universal health coverage remains essentially unexamined, and it limits any claim that the patterns observed are continental rather than specifically American. The review’s title acknowledges this constraint, and it flags a conspicuous gap for researchers working in the Canadian system.

The methodological profile of the review deserves attention. Study selection, data extraction, and risk-of-bias assessment were carried out by a single reviewer using the Joanna Briggs Institute critical appraisal tools, with partial second-rater verification of a subset of studies by an independent subject-matter expert. The author candidly notes that this design may have introduced selection or interpretation bias. Single-reviewer systematic reviews trade speed and feasibility for a measure of subjectivity, and readers should weigh the consistency of findings across studies—which is considerable—against that limitation. The review received no specific grant funding, and the author declares no competing interests.

What did the 21 studies show? Insurance status emerged as one of the most robust correlates. Medicaid coverage was strongly associated with increased burden of both C. difficile infection and surgical site infections. Because Medicaid enrollment is tied to low income, disability, and other markers of socioeconomic disadvantage, the association likely functions as a composite signal: patients on Medicaid may enter care with different comorbidity profiles, different access to outpatient follow-up, and different exposure to healthcare settings with variable infection control resources. Disentangling whether insurance is a causal driver or a proxy for broader disadvantage is a task the included observational studies cannot fully resolve, but the signal appeared repeatedly.

Neighborhood-level deprivation also left a measurable fingerprint. Low-income neighborhoods were associated with higher rates of central line-associated bloodstream infections in pediatric populations, and greater area deprivation—often quantified with composite indices such as the Area Deprivation Index or the Social Deprivation Index—was linked to higher odds of MRSA. These indices aggregate census-level indicators like poverty, housing quality, education, and employment, effectively assigning each patient a socioeconomic context even when individual-level data are missing. The consistency of the neighborhood signal across studies suggests that where patients live shapes both their exposure to healthcare facilities and the conditions under which they are treated within them.

Racial inequities appeared throughout the evidence base. Multiple studies documented that Black patients experienced higher MRSA risk and greater postoperative morbidity compared with White non-Hispanic patients. The review does not attribute these disparities to any single mechanism, and the underlying literature points to several plausible, overlapping contributors: differential exposure to high-infection-risk healthcare settings, differences in comorbid disease burden, potential inequities in the timeliness and quality of care, and structural factors that shape where and how people access the health system. Importantly, the review treats these social variables as associated with incidence, severity, readmission, and mortality—not merely as demographic descriptors to be adjusted away in statistical models.

From an infection prevention standpoint, the findings challenge the standard toolkit. National surveillance systems such as the CDC’s National Healthcare Safety Network track standardized infection ratios by facility and infection type, but they do not routinely stratify outcomes by the social determinants captured in this review. If Medicaid status, neighborhood deprivation, and race are genuinely associated with infection risk and outcomes, then prevention programs that apply identical interventions uniformly across patient populations may systematically underperform for the groups that carry the highest burden. The review argues that social determinants should be integrated directly into surveillance and prevention strategies—an approach that would require linking infection data with insurance claims, census indices, and demographic records, raising both technical and privacy considerations.

The review also sketches an agenda for future research. Because nearly all included studies were observational and many were cross-sectional or relied on administrative databases such as the National Inpatient Sample, causal inference is limited, and the author calls for longitudinal studies that follow socially disadvantaged populations over time to clarify how social determinants influence HAI trajectories from exposure through outcome. The 21-study yield from more than 3,000 screened records underscores how underexplored this intersection remains. As healthcare systems confront persistent disparities in outcomes, this synthesis makes the case that infection prevention cannot be separated from the social architecture of medicine: the same patients who face barriers at every other stage of care also appear to face elevated odds of acquiring an infection in the very institutions meant to heal them.

Subject of Research: Associations between social determinants of health and healthcare-associated infection incidence, severity, and outcomes in the United States

Article Title: Inequities in healthcare-associated infections across North America: a systematic review of U.S.-based studies

Article References: Shahdev, C. (2026). Inequities in healthcare-associated infections across North America: a systematic review of U.S.-based studies. BMC Infectious Diseases. https://doi.org/10.1186/s12879-026-14562-2

Image Credits: AI Generated

DOI: 10.1186/s12879-026-14562-2

Keywords: healthcare-associated infections, social determinants of health, health disparities, MRSA, Clostridioides difficile, systematic review, infection prevention, health equity, Medicaid, surgical site infection, public health, epidemiology