Platelet-rich plasma (PRP) injections are increasingly performed in outpatient settings to treat select musculoskeletal injuries, arthritis, hair loss, and wounds. There is a need for procedure-specific guidance and standardization of PRP practices to mitigate associated infection prevention (IP) risks such as bloodborne pathogen exposure and unsafe injection use.

Develop a standardized approach for PRP administration which incorporates existing IP regulatory and professional society guidance.

Observation and descriptive review of PRP injection protocols across subspecialties at a tertiary medical center, focused on ambulatory IP and regulatory standards compliance. Development of a standardized operating procedure (SOP) to mitigate IP risks and align with regulatory guidance.

Observations were completed in orthopedic, wound care, and oral maxillofacial surgery clinics. Variability in practice was noted for product labeling, centrifugation, and injection modalities. A multidisciplinary workgroup convened to develop and operationalize an SOP. Classification of PRP as a blood product introduced nuances to protocols for product preparation, handling, administration, labeling, and documentation to comply with regulatory standards.

Development and implementation of an SOP for PRP treatment requires an awareness of the scope of practice in a healthcare system and identification of pertinent regulatory standards for integration into workflows. Partnerships between IP teams, subspecialty clinical providers, blood safety experts, quality and safety teams, and healthcare technology are essential to minimize variability in practice, ensure safety of patients and healthcare personnel, and align with regulatory standards.

To evaluate the implementation and effectiveness of a novel home infusion central line-associated bloodstream infection (CLABSI) and home infusion-onset bloodstream infection (HiOB) dashboard and prevention toolkit.

Mixed methods study.

Five home infusion agencies participating in the first CLABSI prevention collaborative.

Agencies uploaded CLABSI and HiOB data to a comparative dashboard. The dashboard started in December 2022 and accepted retrospective data from June 2021. A CLABSI prevention toolkit was made available in June 2024. Using an interrupted time series, we present CLABSI and HiOB rates before and after dashboard and toolkit implementation. We surveyed and interviewed participants about the tools and toolkit, using directed content analysis to analyze the interviews.

After dashboard implementation, there was a decrease in CLABSI (−0.23/10,000 home-CVC days, 95% CI −0.28 to −0.18) and HiOB (−0.25/10,000 home-CVC days, 95% CI: −0.31 to −0.18) over time. With toolkit implementation, there was a further decrease in CLABSI (−0.17/10,000 home-CVC days, 95% CI: −0.30 to −0.044) and HiOB (−0.23/10,000 home-CVC days, 95% CI: −0.37 to −0.089) over time. Themes were associated with use of the tools (accessible, adaptable, patient-centered tools; user-friendly education to enhance understanding; barriers identified; tool mismatches; and strategies for tool delivery) and toolkit implementation (structural barriers, user-centered design, collaborative engagement and communication, toolkit used to enhance workforce competency, and concerns related to consistency).

Implementation of a dashboard and a CLABSI prevention toolkit were each associated with both CLABSI and HiOB reduction in a collaborative of home infusion agencies.

The purpose of the study is to analyze bloodstream infection (BSI) data reported by outpatient hemodialysis facilities to understand temporal trends, the potential impact of infection prevention practices and the COVID-19 pandemic on BSI rates.

Outpatient hemodialysis facilities report BSI data to the National Healthcare Safety Network. We used interrupted time series with mixed effects negative binomial modeling to estimate the annual change of BSI rates from 2012 to 2021, using March 2020 as the COVID-19 inflection point. The model controlled for seasonal factors, vascular access types, and facility characteristics.

The number of facilities used for analysis increased from 5,581 in 2012 to 7,313 in 2021. Most facilities were freestanding (range: 90%–93%) and belonged to for-profit organizations (range: 85%–88%). The annual adjusted BSI rates decreased by an average of 8.90% (95% CI: −9.10 %, −8.71%) January 2012-February 2020. The annual decrease in BSI rate was not significant during March 2020-December 2021 (P = 0.15). There was a level drop of 32.03% (95%CI: −33.84%, −30.17%) in BSI rates in the period of March 2020-December 2021 compared with the period of January 2012-February 2020.

BSI rates decreased steadily from January 2012 to February 2020 likely due to the identification and adoption of evidence-based prevention practices. BSI rates plateaued at lower levels during March 2020-December 2021. This suggests that infection prevention measures implemented by facilities prior to the emergence of COVID-19 contributed to substantial decreases in BSI rates and may have helped to stabilize BSI rates after March 2020.

Develop and implement a framework for reviewing hospital-onset bacteremia and fungemia (HOB) events to identify quality improvement opportunities.

Prospective, observational study.

Six hospitals (3 academic and 3 community) associated with two health systems.

Clinical team members involved in the care of patients with eligible HOB events.

The Joint Commission Patient Safety Event Taxonomy was adapted to develop a framework for HOB, eliciting potential contributing factors in four categories: general infection prevention, infection-site-specific, system, and human factors. From 9/2022 to 4/2024, HOB events identified from hospital blood culture databases were selected using convenience sampling to a target enrollment of 75 events, limiting inclusion of events associated with neutropenia or central line infections. Multidisciplinary case reviews were performed, and the framework was refined using feedback from the first 17 reviews. We summarized HOB sources, contributing factors, and improvement opportunities using descriptive analyses.

Seventy-four HOB case reviews were analyzed, evenly distributed between academic and community hospitals, and 42% occurred in an ICU setting. A median of 3 care team members (IQR 2–4) participated in each review. At least one infection-site-specific factor was identified in 48% of case reviews, representing 63% of HOB events with a known source of infection. 50% of cases identified a general infection prevention factor, 35% a system factor, and 34% a human factor. 57% of the cases had an actionable finding.

HOB events have diverse causes and elements of preventability, and multidisciplinary review can generate actionable findings beyond the current guideline-defined measures.

Carbapenem-resistant Acinetobacter baumannii (CRAB) carriage in post-acute care hospitals (PACH) reflects both importation of colonized patients and within-PACH transmission. We studied within-PACH transmission by examining the sameness of CRAB clusters, as identified by Fourier-transform infrared (FTIR) spectroscopy.

We conducted a point-prevalence survey in 55 wards in 18 Israeli PACH in 2021. Patients (n = 1,733) were screened for CRAB, and 461 isolates from 357 patients underwent FTIR typing (IR Biotyper, Bruker). We assigned each patient isolate to its cluster and paired each patient-cluster combination with every other patient-cluster combination. We examined the relationship between physical proximity of pairs (n = 75,047) and FTIR cluster sameness using generalized estimating equation logistic regression. To estimate within-ward transmission, we compared proportions of cluster sameness within wards versus between institutions.

The 461 CRAB isolates formed 23 FTIR clusters. Compared to being in different institutions, being in the same ward was associated with significantly higher odds of sharing the same cluster (odds ratio: 3.6, p < 0.001). Odds ratios were highest for patients in the same room (6.2) or adjacent rooms (6.1) (p < 0.001 for both). Based on same-cluster pairs we estimated that 70% of prevalent CRAB cases resulted from within-ward transmission.

CRAB strain similarity was strongly associated with spatial proximity within PACH wards, indicating that within-ward transmission is an important contributor to CRAB carriage prevalence. Similar risk in same and adjacent rooms suggests transmission via shared staff or equipment. Ward-level infection control interventions are warranted to interrupt spread.

To evaluate the incidence of hospital-onset bacteremia and fungemia (HOB) among solid organ malignancy (SOM), hematologic malignancy (HM), and hematopoietic cell transplant (HCT) therapy patients at a large cancer care center.

A single-center, observational, retrospective analysis was conducted for hospitalizations between January 1, 2018, and September 30, 2024, to identify patients with a first positive blood culture on or after day four of hospitalization. Hospitalizations were grouped into three categories: SOM, HM with HCT, and HM without HCT. The primary objective was to study the incidence of HOB. Secondary objectives: identification of risk factors for HOB events and pathogens associated with HOB events.

In 45,896 admissions, 1,470 HOB events were identified (incidence: 3.2%). The incidence of HOB was highest in the HM/HCT cohort (3.8%), followed by HM without HCT (2.3%) and SOM (0.9%). Risk factors of HOB identified included HM (OR 1.49), hospitalization within the past 90 days (OR 1.50), length of stay greater than or equal to 30 days (OR 6.74), intensive care unit (ICU) admission (OR 4.06), development of a CAUTI during admission (OR 23.23), or presence of a central line (OR 51.61). The most common pathogens were Escherichia coli (20.1%), coagulase-negative Staphylococci (19.0%), and Viridians streptococci (11.3%).

This study highlights the high incidence of HOB among cancer and HCT patients. The risk factors and differential rates of HOB in subpopulations of this demographic may help to inform targeted infection prevention efforts in cancer centers.

To define the incidence of donor-derived infection (DDI) in recipients of solid organ transplant (SOT) from donors with positive blood cultures and to assess the impact of shorter versus longer duration of targeted preemptive antibiotic therapy (PAT).

Retrospective, single-center, cohort study.

Mayo Clinic Arizona.

Recipients transplanted between 1/1/2019 and 7/1/2024 who received an organ from a donor with positive blood cultures.

The primary outcome was incidence of DDI. Secondary outcomes included duration of PAT and incidence of donor blood culture contamination.

Among 199 SOT recipients from 167 unique donors with positive blood cultures, two recipients developed confirmed DDI within 30 days of SOT. Both cases were gram negative bacillary bacteremia not treated in donors and occurred immediately posttransplant prior to adequate recipient PAT. Six-month graft survival and recipient survival were 96.5% and 97.5% respectively. 139 recipients (69.8%) received PAT for a median duration of 7 days. There was no difference in rate of infections between recipients provided with ≤7 days versus 8–14 days of PAT for donor blood cultures; however, recipients who received 8–14 days had more Clostridioides difficile infections (CDIs) within 60 days of SOT (7.7% vs 1.5% ≤ 7 days, P = .040) and were more often discharged on intravenous antibiotics (32.3% vs 11.3%, P < .001).

We observed a low rate of DDI following receipt of organs from donors with positive blood cultures. DDI occurred in cases without adequate donor/recipient treatment. Longer durations of targeted PAT resulted in more CDI and intravenous antibiotics on discharge.

An improved understanding of the epidemiology of hospital-onset methicillin-resistant Staphylococcus aureus bloodstream infection (HO-MRSA BSI) could inform future prevention strategies for HO-MRSA BSI.

We performed a retrospective cohort study of HO-MRSA BSI reported to NHSN from 2020–2023 at a system of 9 acute care hospitals located in New York City. The primary outcome was to describe the demographic and clinical characteristics of patients with HO-MRSA BSI. Secondary outcomes included comparisons of tertiary (TH) and community (CH) hospitals, standardized infection ratio (SIR) and rates per 10,000 patient-discharges, presumptive potential infectious sources, and mortality.

Between 2020 and 2023, 222 patients had HO-MRSA BSI. Their median age was 65 years, 139 (63%) were male, 92 (41%) had central lines, 89 (40%) were in ICUs, and 63 (28%) were on a ventilator. These characteristics were similar across the 176 (79%) patients in TH and the 46 (21%) patients in CH. SIRs were similar across each year of the study (with cumulative SIRs of 0.815 overall, 1.412 [CH] and 0.732 [TH]). Overall HO-MRSA BSI rates ranged from 2.58–3.53 per 10,000 patient-discharges. The most common sources of HO-MRSA BSI were pneumonia (41%), SSTIs (17%), CLABSIs (13%), and PIV catheter-related issues (9%). The all-cause mortality rate was 35%.

The unchanged HO-MRSA BSI SIRs in this study support the need for additional interventions that focus on prevention of the primary sources of MRSA infections. Ongoing systematic surveillance of the primary sources of HO-MRSA BSI should be implemented to inform and monitor best practices for prevention.

nvHAP (nonventilator hospital-acquired pneumonia) can affect all non-intubated patients, and semi-automated systems enable incidence surveillance. This feasibility study evaluated the performance and implementation of a semi-automated nvHAP surveillance in Swiss acute care hospitals.

Multicenter feasibility study

Seven Swiss acute care pilot hospitals representing different sizes and language regions

Inpatients of the participating hospitals.

Hospitals implemented an adaptable nvHAP selection algorithm including one to five indicators (radiology procedure, radiology report, leukocytes, body temperature, intubation). Five hospitals performed manual review on the preselected patients following standardized definitions. Performance characteristics of the algorithms (i.e., sensitivity and percentage records to manually review) and time investment to implement the semi-automated surveillance were evaluated. Barriers and facilitators for implementation were identified through interviews.

Hospitals implemented algorithms including one, two, four and five indicators. Sensitivity ranged from 98% to 100% in larger hospitals. Percentage of records to manually review ranged from 1% to 6% in hospitals that surveyed the total patient population and was 13% in one hospital that focused on two high-risk departments. Time for technical implementation varied from 55 to 437 hours. Mean time for manual review per preselected patient was 14 minutes and decreased with experience. Implementation facilitators included preprocessed data, team experience in similar projects, and external support.

Semi-automated nvHAP surveillance was feasible and sufficiently sensitive regardless of the algorithm. It required effort for setup and manual review. Algorithm adaptability enabled the implementation in hospitals with limited electronically available data or IT resources.

Vancomycin overuse in pneumonia should be a key target for antimicrobial stewardship according to Centers for Disease Control and Prevention. High negative predictive value of nasal Methicillin Resistant Staphylococcus aureus (MRSA) polymerase chain reaction (PCR) (nMP) screening for pneumonia has been shown. We implemented informatics-based ASP intervention to reduce vancomycin use in pneumonia by 20% in 6 months.

Quasi-experimental: Pre-intervention period (P1: 4/1/24–9/30/24) compared with post-intervention period (P2: 10/15/24–3/15/2025).

Quality improvement (QI) initiative in a tertiary-care center in Upper Midwest.

Hospitalized pneumonia patients.

Automated default nMP order was incorporated in pneumonia order-set in electronic medical record while ordering vancomycin for hospital acquired/ventilator associated pneumonia, severe community acquired pneumonia.

Outcome measures declined significantly: Average vancomycin use density as reported with days of therapy (DOT)/1,000 patient days decreased by 49.5% (from 72.2 DOT/1,000 patient days in P1 to 36.3 DOT/1,000 patient days in P2; p < .0001). Average vancomycin drug inventory cost decreased by 50% (from 1,089.5 U.S. Dollars (USD)/1,000 patient days in P1 to 546.3 USD/1,000 patient days in P2; p < .0001). All process measures showed significant changes: nMP ordering increased to 100% in P2 (p < .0001); proportion of pneumonia patients with negative PCR results with discontinuation of vancomycin within 48–72 hours increased to 71% (p < .0001) and time to vancomycin discontinuation declined by 46% (p < .001). Balancing measures (readmissions; nMP order-to-result time) remained unchanged.

Informatics-based ASP intervention was transformative leading to significant decline in vancomycin utilization, considerable healthcare-cost savings and significant increase in nMP screening among pneumonia patients.

Despite the availability of straightforward and economic interventions to prevent HAIs, these unintentional adverse events still pose a significant challenge to public health globally. We aimed to evaluate the outcomes of a nationwide project designed to mitigate HAI incidence in intensive care units (ICUs) using the Model of Improvement framework.

A Quality Improvement (QI) study assessing the outcomes of a two-year initiative in Brazilian ICUs from September 2021. A customized Collaborative methodology was applied to mentor and enhance the capabilities of healthcare workers, equipping them with evidence-based, structured, systematic, and auditable QI strategies (prevention bundles) to improve patient care outcomes. A one-year preintervention baseline incidence was established for the three critical HAIs: central line-associated bloodstream infections (CLABSI), ventilator-associated pneumonia (VAP), and catheter-associated urinary tract infections (CAUTI), to compare with the intervention period.

The initiative encompassed 188 ICUs (169 adults, 11 pediatric, and eight neonatal), recording substantial reductions in HAI incidence density: by 43% for CLABSI (from 5.5 to 3.2 per 1,000 catheter-day), by 51% for VAP (from 13.6 to 6.7 per 1,000 ventilator-day), and by 55% for CAUTI (from 3.2 to 1.4 per 1,000 catheter-day), irrespective of age. Implementing this QI strategy prevented an estimated 7,342 infections.

Our initiative has been demonstrated to be a feasible and valuable strategy for preventing HAIs in critical care settings. The success of this approach emphasizes the potential for its broader application and reinforces the need for systematic, evidence-based interventions in healthcare settings.

There is increasing evidence on the effectiveness of prevention bundles against non-ventilator hospital-acquired pneumonia (nvHAP), but detailed reports on their implementation are lacking. This study aims to describe and structure the implementation activities undertaken in a single-center multimodal intervention that achieved a 31% reduction in nvHAP incidence.

Longitudinal descriptive qualitative study.

Nine medical and surgical departments of a Swiss university hospital.

Healthcare professionals and implementation teams in study departments.

We collected longitudinal data on implementation activities using (1) implementation activity logs, (2) drop-in interviews and observations, (3) “action plan meetings,” (4) focus groups, and (5) unstructured recall sessions among the project team. Data were deductively coded using the “Expert Recommendations for Implementing Change” taxonomy, specified using Proctor et al.’s “Recommendations for specifying and reporting implementation strategies” and mapped to the “Exploration, Preparation, Implementation, Sustainment” framework phases.

A total of 174 activities were undertaken. Activities varied by implementation phase, most frequently involving “evaluative and iterative strategies,” “develop stakeholder interrelationship strategies” and “training and education of stakeholders” during Exploration, Preparation, and Implementation, respectively. During Implementation, 54% of activities were initiated by department nurses, and 27% were initiated by the institutional implementation team. Activities included interdisciplinary kick-off events, education in various formats, posters, informational stickers for patients, provision of new equipment (e.g., toothbrushes), and electronic medical records order sets.

This report offers valuable insights for future implementation efforts by providing a structured overview of the concrete implementation activities performed in a successful one-hospital multimodal nvHAP prevention project.

Racial and ethnic disparities in healthcare-associated infections (HAIs) could have significant implications for hospital-based incentive programs. We sought to quantify racial and ethnic disparities in HAIs across inpatients in the United States.

Systematic Review and Meta-Analysis.

Medline, Embase, and Scopus were searched 2008–2022 for English language studies describing reportable HAIs among inpatients and references to race or ethnicity. Studies were excluded if they used an aggregate outcome of “infection,” described a non-acute care setting, or measured a respiratory virus. Meta-analysis was performed using random-effects model on pooled continuous outcomes with 3 or more studies.

39 studies met criteria for inclusion; 23 evaluated surgical site infections (SSI), 6 evaluated hospital-onset Clostridioides difficile infection (HO-CDI), 5 evaluated central line-associated bloodstream infections (CLABSI), and 8 examined other HAIs. There was a high degree of heterogeneity across studies. Meta-analysis was performed for 10 distinct HAI/risk factor combinations. Race and ethnicity were not associated with SSIs (Black vs White OR 1.19, 95% CI 0.95–1.48; Hispanic vs White OR 1.01, 95% CI 0.78–1.31). Hispanic patients had lower risk of HO-CDI relative to White patients (OR 0.80, 95% CI 0.64–0.98). Black (OR 1.36, 95% CI 1.07–1.70) or Hispanic (OR 1.16, 95% CI 1.073–1.249) patients had increased risk of CLABSI compared with White patients.

Racial and ethnic disparities were observed in rates of HAIs, specifically for CLABSI and HO-CDI. However, conclusions are limited by the substantial heterogeneity present. Further research characterizing social determinants of health driving these disparities is needed.

To identify modifiable surgical practices associated with reduced sternal wound infection rates following isolated coronary artery bypass grafting (CABG) using positive deviancy methodology.

Retrospective cohort study with prospectively collected data (January 2021–June 2025).

Single tertiary referral cardiac surgery center.

3,087 consecutive patients undergoing isolated CABG.

Primary outcome was total sternal wound infection (deep and superficial combined) within 30 days. Risk-adjusted surgeon performance was evaluated using mixed-effects logistic regression with observed-to-expected (O/E) ratios. Positive deviants were defined as surgeons with O/E ratios <1.0 with 95% confidence intervals excluding unity. Surgical techniques were systematically reviewed through anonymized surveys, and volume-weighted analysis compared techniques of better and worse performers.

Total sternal wound infection occurred in 175 patients (5.7%). Nine surgeons were stratified: better performers (O/E <1.0, n = 5), worse performers (O/E ≥1.2, n = 3), and average performers (O/E 1.0–1.19, n = 1). One surgeon achieved statistically significant superior performance (O/E = 0.590, 95% CI: 0.39–0.91), representing 41% fewer infections than expected across 543 cases. Four protective techniques were identified: wound irrigation at closure (100% vs 0%), double skin preparation with chlorhexidine and povidone (100% vs 0%), superior Ioban adherence quality (5/5 vs 3.7/5 vs 3.2/5, P < .001), and minimal cautery usage (1.0/5 vs 3.2/5 vs 3.5/5, P < .001).

Positive deviancy methodology successfully identified four modifiable surgical practices associated with reduced total sternal wound infections. These techniques represent immediately implementable interventions for infection prevention in cardiac surgery. Further study is needed to validate these findings across multiple institutions and evaluate implementation outcomes.

A semi-automated surveillance system for surgical site infections (SSIs), SPICMI (Surveillance and Prevention Program for Infectious Risk in Surgery and Interventional Medicine), has been implemented in French hospitals, leveraging data from electronic health records (EHRs).

To evaluate the performance of the SPICMI algorithm in detecting SSIs in orthopedic and digestive surgery.

Surveillance data were collected annually from the EHRs. The algorithm identified suspected SSIs based on two criteria: (1) surgical revision during the index stay or readmission, (2) positive microbiological samples from the wound. Suspected SSIs identified were subsequently validated by surgeons.

A stochastic modeling approach was used to estimate probability intervals for performance indicators. Various detection scenarios were constructed based on SPICMI criteria. Logistic regression analysis was performed using surveillance data. Data unavailable in the database were estimated through a literature review and expert opinions.

The probability of surgical revision following an SSI varied significantly between surgical specialties, ranging from 92% in orthopedic surgery to 45.2% in gynecology. In orthopedic and digestive surgery, the SPICMI algorithm demonstrated good reliability for detecting SSIs in minimizing false-negative and false-positive cases (Youden index: 0.96 and 0.79, respectively). Sensitivity (Se) was lower in digestive surgery (0.7–0.9) compared to orthopedic surgery (0.9–1), while specificity (Sp) remained high (0.9–1) in both specialties.

The SPICMI algorithm shows potential to support efficient use of time and resources in SSIs surveillance management. Further evaluation is needed with a broader panel of surgery procedures.

Hospital sinks are reservoirs for epidemiologically important pathogens (EIPs), yet practical, effective strategies for sustained decontamination are lacking.

We conducted a randomized controlled trial of 30 in-room sinks (15 intervention, 15 control) in a newly renovated hospital unit to evaluate the efficacy of a hydrogen peroxide/peracetic acid foamed disinfectant in reducing sink contamination. Intervention sinks received foamed disinfectant to sink drains three times weekly; control sinks underwent standard daily surface cleaning. Weekly sampling was performed from three sink locations (top surface, tail pipe, P-trap) over 35 weeks. The primary outcome was sink conversion events (SCEs), defined as first detection of ≥1 EIP, defined as Pseudomonas aeruginosa, Stenotrophomonas spp., or Acinetobacter spp., and ESBL-producing or carbapenem-resistant Enterobacterales, in previously negative sinks.

A total of 2880 samples were collected. All sinks were negative at baseline for study pathogens. Nearly all sinks (29/30) experienced an SCE during the study period. However, only 44 (9%) intervention sink samples were positive for EIPs, compared to 270 (47%) in control sinks (p < 0.00001). EIPs were recovered from 4% versus 24% of P-traps and 4% versus 39% of tail pipes; sink top/handle contamination was rare and similar (3% vs 4%). The most frequent EIPs were Acinetobacter spp. and Stenotrophomonas spp. Intervention sinks experienced a delayed time to SCE (p = 0.0001). Items were stored on/in sinks in 93% of observations.

Regular application of a foamed disinfectant reduced and delayed EIP contamination in renovated hospital sinks. Foam-based protocols may help mitigate environmental reservoirs of multidrug-resistant organisms.

Older adults (≥65) often receive antibiotics in emergency departments (ED), where guideline concordance is low with both overuse and underuse; whether community disadvantage drives these patterns is unknown.

We analyzed electronic health records from 1,318,281 ED encounters among 790,562 adults ≥65 (2015–2024). Outcomes were guideline concordance and components (overuse, underuse). To address omitted variables and reverse causality, we used two-stage instrumental-variable models with Social Vulnerability Index (SVI) and Social Deprivation Index (SDI) as exposures, instrumented by maximum state Earned Income Tax Credit, adjusting for patient, facility, state, and time covariates.

16.8% of encounters were non-concordant (overuse 9.5%; underuse 7.2%). Concordance improved to 83.8% in 2024. In IV models, each 10-point increase in SVI reduced concordance by 6.37 percentage points (pp) (SE 0.69) and each 10-point increase in SDI by 1.84 pp (SE .20; P < .0005). Declines reflected higher underuse (+0.43 pp per 10-point SVI; +0.12 pp per 10-point SDI) with less overuse (−0.10 and −0.30 pp). Concordance was higher for Black (+12.90 pp vs White) and Medicaid-insured patients (+5.40 pp vs commercial). Overuse was higher in rural (+7.90 pp vs metropolitan) and academic EDs (+5.00 pp vs non-academic), whereas underuse was more common in metropolitan (+42.50 pp) and non-academic EDs (+32.70 pp). Spatial analyses found high deprivation/low concordance in the South and low deprivation/high concordance in the Midwest.

Community disadvantage may causally predict lower guideline-concordant antibiotic prescribing for older adults, primarily via underuse. Stewardship should address underuse and overuse and prioritize disadvantaged regions where gaps are greatest.