1. Introduction
Healthcare-associated infections (HAIs) remain a major threat to patient safety in North America. In the United States, the Centers for Disease Control and Prevention (CDC) estimates that about 687,000 HAIs occur each year, leading to nearly 72,000 hospital-associated deaths[1]. Despite decades of prevention efforts, conditions such as surgical site infections (SSIs), central line-associated bloodstream infections (CLABSI), catheter-associated urinary tract infections (CAUTI), ventilator-associated pneumonia (VAP), methicillin-resistant Staphylococcus aureus (MRSA), and Clostridioides difficile infection (CDI) remain persistent[2, 3], These conditions cause morbidity, mortality, longer hospital stays, and increased healthcare costs [4].
While clinical risk factors and hospital practices are central to prevention, there is growing evidence that HAIs do not occur uniformly across populations [5, 6]. Several studies have documented the role of social determinants of health, including socioeconomic status, insurance type, race and ethnicity, poverty level, household condition, neighborhood deprivation, which significantly influence HAI risk, severity and outcomes. These disparities contribute to patient access to care, exposure to the healthcare environment, timely diagnosis and quality of treatment [7–9].
Moreover, public health reports have documented that marginalized communities in the U.S. and Canada face a disproportionate burden of HAIs. They intersect with healthcare environment exposure, contributing to systematic differences in HAI incidence and severity [10, 11]. Despite efforts to achieve equity in infection prevention and healthcare quality [5], evidence linking SDOH and HAI remains scattered across study designs, populations, and infection types.
Although one recent study has begun to examine how social and structural factors contribute to differences in HAI type and severity, however, the evidence has not been comprehensively synthesized [12]. A systematic understanding of these relationships is essential for developing infection prevention strategies that address not only clinical and procedural risks but also the upstream social factors that shape patients’ vulnerability to acquiring HAIs. Such insights are critical for strengthening health system equity efforts, informing targeted prevention initiatives, and guiding policies aimed at improving outcomes among socially disadvantaged populations disproportionately affected by HAIs.
To our knowledge, no systematic review has evaluated the influence of social determinants on HAIs across North America. Hence, the objective of this systematic review is to synthesize current evidence on the association between social determinants of health and healthcare-associated infections in North America. The review aims to recognize consistent patterns of disparities, methodological gaps, and policy recommendations to strengthen infection prevention strategies and equity-focused efforts to reduce HAIs.
4. Discussion
A
This systematic review synthesizes 21 studies examining how social determinants of health (SDOH) influence healthcare-associated infections (HAIs) across North America. Across HAI types including CDI, MRSA, CLABSI, CAUTI, VAP, and SSI, the findings consistently show that structural and social inequities significantly impact HAI risk, severity and outcomes (Table 1).
Table:1 Characteristics of studies on social determinants of health and healthcare-associated infections: HAI Type, Study Design, Setting,
SDOH Variable and Findings
A
|
Study (Author, Year)
|
HAI Type
|
Study Design &
Data Source
|
Population/ Setting
|
SDOH
Assessed
|
Findings
|
|
|
1. Shaka et al.,
2022 [14]
|
VAP
|
Retrospective (2016–2017); NIS
|
33,140 VAP; nationwide
|
Insurance
|
|
• Uninsured ↑ mortality with VAP
(aOR 2.13; 95% CI 1.49–3.06).
|
|
|
|
2. Argamany et al.,
2016 [8]
|
CDI
|
Retrospective (2001–2010); NHDS
|
1,676,903 CDI;
nationwide
|
Race
|
• Black race ↑ mortality (aOR 1.12; 95% CI 1.09–1.15).
• Severe CDI (aOR 1.09; 95% CI 1.07–1.11).
• Shorter LOS (aOR 0.94; 95% CI 0.93–0.94).
• CDI incidence ↑ White patients (7.7 vs 4.9 per 1,000 discharges, p < 0.0001).
|
|
|
3. Olsen et al.,
2023 [9]
|
CDI
|
Retrospective (2011–2017); MarketScan Commercial and Medicaid
|
71,668 CDI;
nationwide
|
Insurance
|
• ↑ CDI incidence: Dual-eligible had 3.1 ↑CDI than Medicare-only; younger Medicaid had 2.7 ↑CDI than commercially insured.
• Trend: HCA-CDI rates ↓ across Medicaid and Medicare groups but remained stable in commercially insured younger adults.
• Comorbidity effect: Medicaid-insured with chronic or immunocompromising conditions had 2.7–2.8 ↑ CDI; even without comorbidities CDI remained ↑ (67.5 vs 45.6/100k PY).
|
|
|
4. Ramai et al.,
2020 [15]
|
CDI
|
Retrospective (2006–2015); HCUP- NIS
|
76,124 CDI; nationwide
|
Insurance; hospital type; region
|
|
• Mortality ↓ markedly: CDI 5.9%→1.4%
|
|
• Medicare highest CDI incidence & mortality
|
|
• Predictors of mortality: ↑Age, ↑LOS, Medicare
|
|
|
|
5. Scaria et al.,
2021 [16]
|
CDI
|
Retrospective (11 months of 2014); Medicare
|
19,490 CDI
|
Neighborhood ADI; dual eligibility; race; rurality; neighborhood poverty
|
• Most disadvantaged neighborhood 16% ↑ odds of readmission than least groups (OR 1.16; 95% CI 1.04–1.28)
|
|
|
6. Vader et al
2021 [17]
|
CDI
|
Case–control
(2014–2018);
EMR
|
170 CDI cases, 324 controls; safety-net hospital
|
SDI; insurance; race
|
• No association with SDI or race.
• Medicare pts had 2× odds (aOR 2.04; 95% CI 1.31–3.20) vs private insurance
|
|
|
7. Warren et al.,
2024 [18]
|
CDI
|
Retrospective (2015–2021); EHR
|
35,160 tests;
3 hospitals
|
Race
|
• White patients received more CDI tests than Black or NWNB patients (14.46 vs 12.96 vs 10.27/1,000 patient-days)
• Test positivity is similar for White and Black patients (15% each), but lower in Non-white and non-black patients (12%; P = .006).
|
|
|
8. Gutierrez et al.,
2023 [19]
|
CLABSI
(Pediatric)
|
Retrospective (2018–2023); PHIS
|
1,210 CLABSI;
24 hospitals
|
Low-income neighborhood
|
• Low hospital-level neighborhood income was linked to ↑CLABSI risk (RR 1.43; 95% CI, 1.10–1.84; p < 0.01).
|
|
|
9. Lyren et al.,
2024 [7]
|
CLABSI
(Pediatric)
|
Cross-sectional,
SPS-
Multicenter study data
|
148 SPS; hospitals
|
Race/Ethnicity
|
• CLABSI rates were 2.6–3.6 SD ↑ in Multiracial Hispanic and Combined Hispanic–Pacific Islander patients, White patients consistently had significantly lower harm rates than reference values.
|
|
|
10. Gettler et al.,
2023 [20]
|
CLABSI, CAUTI
|
Retrospective (2018–2021)
Academic Medical Center Surveillance data, Durham NC
|
450 CLABSI,
233 CAUTI
|
Race/Ethnicity
|
• CLABSI rates were ↑ among non-Hispanic Black (IRR 1.27; 95% CI 1.02–1.58) and other race patients (IRR 2.25; 95% CI 1.31–3.88)
• CAUTI rates were ↑ among non-Hispanic Black (IRR 1.42; 95% CI 1.05–1.92) and Asian patients (IRR 2.49; 95% CI 1.16–5.36) compared with non-Hispanic White patients
|
|
|
11. Andreatos et al.,
2018 [21]
|
MRSA
|
Retrospective (2013–2015);
Medicare
|
26,928 MRSA
|
Poverty level, Education, Housing quality
|
• Poverty ↑ MRSA
(Coeff 0.094, 95% CI 0.034–0.155, P = 0.002).
• Higher education levels ↓ MRSA (Coeff − 0.037, 95% CI − 0.068 to − 0.005, P = 0.024).
• Better housing quality (more rooms per home) ↓ MRSA (Coeff − 0.107, 95% CI − 0.134 to − 0.081, P < 0.001).
• Income slightly above poverty line ↓ MRSA (Coeff − 0.257, 95% CI − 0.314 to − 0.199, P < 0.001).• |
|
|
12. McGarry et al.,
2023 [22]
|
MRSA, MSSA
(Pediatric)
|
Longitudinal cohort; Cystic Fibrosis Foundation Patient Registry
|
10,640 CF
|
Race/Ethnicity (Hispanic vs non-Hispanic White).
|
• Hispanic pwCF had a 19%↑risk of MSSA acquisition (HR 1.19, 95% CI 1.10–1.28, p < 0.001) than non-Hispanic pwCF.
• Hispanic pwCF had a 13% ↑ risk of MRSA acquisition (HR 1.13, 95% CI 1.02–1.26, p = 0.02) than non-Hispanic pwCF.
• Hispanic children acquired MSSA earlier (median 3.8 vs 4.9 years, p < 0.001) and MRSA earlier (median 20.8 vs 22.4 years, p = 0.02) than non-Hispanic pwCF.
|
|
|
13. Freeman et al.,
2018 [23]
|
MRSA
|
Ecological cross-sectional study; CDC state-level SIR for HO-MRSA bloodstream infections
|
Population level data
|
Race/Ethnicity poverty rate, income
|
• Poverty, income inequality, % African American, and % diabetes (2013 only) was positively correlated with higher HO-MRSA rates (univariate).
• No association with % Hispanic, median income, or % ≥65.
• In multivariable models, % African American remained the only significant predictor of HO-MRSA across both 2013 and 2014.• |
|
|
14. Oates et al.,
2019 [9]
|
MRSA
(Pediatric)
|
Cross-sectional observation; Cystic Fibrosis Center Patient Registry
|
231 pediatric CF
|
ADI (high ≥ 5 vs low < 5), rurality, parental education, household income, race
|
• ↑Neighborhood deprivation strongly correlated with rural residence, no parental college education, and lower household income (all P < 0.001).
• High neighborhood deprivation associated with > 2-fold ↑ MRSA infection (OR 2.26; 95% CI 1.14–4.45), P < 0.05.
|
|
|
15. Sood et al.,
2023 [24]
|
MRSA
|
Retrospective (2016–2018); EMR (Epic) Premier Quality Advisor database; ADI
|
220,849 cases
5 hospitals in one large Maryland-Washington DC health system
|
ADI, Race/ethnicity, Insurance
|
• Black race had 44% ↑ MRSA
(OR 1.44; 95% CI 1.18–1.76).
• After adjusting for ADI, Black race was no longer associated with ho-MRSA, indicating ADI mediated the disparity.
• Asian and “unknown” race remained associated with lower odds of co-MRSA/MSSA in adjusted models.
|
|
|
16. Arsoniadis et al.,
2016 [25]
|
SSI
|
Retrospective (2005–2013); NSQIP-PUF
|
9,513 CD patients
|
Race (African American AA vs non-AA)
|
• SSI risk ↑ among AA: 17.6% vs 14.8%, p = 0.037
|
|
|
17. Qi et al.,
2019 [26]
|
SSI
|
Cross-sectional.
State Inpatient Database
|
149,741patients
7 U.S. states
|
Race/ethnicity, income, insurance
|
• 30-day SSI rate: 2.55% after colectomy; 0.61% after hysterectomy.
• Colectomy cohort: Black race associated with lower SSI risk → (aOR 0.71; 95% CI 0.61–0.82).
• Medicare insurance → ↑ SSI risk → (aOR 1.25; 95% CI 1.10–1.41).
• Medicaid insurance → ↑ SSI risk → (aOR 1.23; 95% CI 1.06–1.44).
• Lowest ZIP-code income quartile → ↑ SSI risk → (aOR 1.14; 95% CI 1.01–1.29).
• Hysterectomy cohort: No SDOH (race, insurance, income) showed a significant association with SSI after adjustment.
|
|
|
18. Stevens et al.,
2023 [27]
|
SSI, CLABSI
|
Retrospective (2010–2020);
Children’s Hospital Colorado trauma registry, EMR, CDC-SVI 2018
|
355 pediatric trauma patients (< 18 y), single center study
|
Overall, SVI (≥ 70th percentile = high vulnerability) SVI subcomponent Socioeconomic status, Household /disability, Minority /language, Housing/transportation
|
• SSI higher in ↑ SVI → 3.9% vs 0.4% (P = 0.03).
• No significant differences in rates of postoperative pneumonia, UTI, DVT, or CLABSI by SVI status.
|
|
|
19. Welter et al.,
2023 [28]
|
SSI
|
Retrospective (2017);
ACS-NSQIP
|
740,144 patients; 10 surgical specialties: general surgery (GS), vascular surgery (VS), cardiac surgery (CS), thoracic surgery (TS), orthopedics (OS), neurosurgery (NS), urology (US), otolaryngology (ENT), plastic surgery (PS), and gynecology (GYN).
|
Race: Black African American (BAA) to White non-Hispanic (WNH)
|
• WNH had ↑ SSI in GS (4.4% vs 4.1%, p = 0.003) and TS (3.1% vs 1.7%, p = 0.015)
• BAA had ↑ SSI in VS (4.4% vs 3.2%, p < 0.001), OS (1.6% vs 1.2%, p < 0.001), and GYN (3.0% vs 2.4%, p < 0.001), with similar rates in ENT and US.
|
|
|
20. Yi et al.,
2019 [29]
|
SSI
|
Retrospective (2011–2013); state inpatient discharge database
|
291,757 cesarean deliveries,
California
|
Insurance
|
• Cesarean deliveries covered by Medicaid had ↑ SSI risk
(aOR 1.40; 95% CI 1.20–1.60, p < 0.0001)
• SSI incidence by insurance type: Medicaid: 0.75% (1,055 infections), Private insurance: 0.63% (955 infections)
• Medicaid covered nearly half of cesarean deliveries (48%), indicating large population-level inequality exposure.
|
|
|
21. Taree et al.,
2021 [30]
|
SSI
|
Retrospective (2012–2014)
HCUP
|
65,121 patients; 191 SSI readmissions (30-day) and 283 SSI readmissions (90-day)
|
Insurance
|
• Medicare and Medicaid patients had significantly higher odds of SSI-related readmission at both 30 and 90 days (P < 0.0001).
• Medicaid insurance was an independent predictor of SSI readmission in adjusted models at 30 and 90 days (multivariable).
|
|
CF, Cystic Fibrosis; CD, Crohn’s Disease
SDOH, social determinants of health; ADI, Area Deprivation Index; Social Vulnerability Index; SDI, Social Deprivation Index; LOS, length of stay.
NIS, National Inpatient Sample; NHDS, National Hospital Discharge Survey; HCUP, Healthcare Cost and Utilization Project; ACS-NSQIP, American College of Surgeons- National Surgical Quality Improvement Program; PHIS, Pediatric Health Information System; SPS, Solutions for Patient Safety; EMR, electronic medical record; EHR, electronic health record.
aOR, adjusted odds ratio; IRR, incidence rate ratio; HR, hazard ratio; RR, rate ratio; CI, confidence interval; PY, person-years.
Racial and Ethnic Disparities
Several studies in this review show racial disparities across various types of HAIs, with Black people remain the most common affected groups among others [8, 18, 20, 23, 24, 28]. In CDI, Black patients had significantly higher mortality (aOR 1.12; 95% CI 1.09–1.15) and greater odds of severe disease (aOR 1.09; 95% CI 1.07–1.11) compared to Whites, despite White patients having a higher crude incidence rate of CDI-related hospitalizations [8]. CDI testing patterns also reflected inequities: White patients had more CDI tests per 1,000 patient-days than Black or non-White patients, although positivity rates were similar, this suggests potential differences in diagnostic access for clinical decisions [18].
Similarly, device associated infections also show pronounced disparities. Non- Hispanic Black patients had significantly higher CLABSI rates (IRR 1.27; 95% CI 1.02–1.58) and higher CAUTI rates (IRR 1.42; 95% CI 1.05–1.92) compared to non-Hispanic White patients [20]. Pediatric studies also revealed that multiracial Hispanic and Hispanic- pacific Islander children experienced higher CLABSI rates above reference values for race, whereas White children consistently had lower risk [7].
Racial disparities were also dominant in MRSA and MSSA. Hispanic children with cystic fibrosis had a 19% higher risk of MSSA (HR 1.19; 95% CI 1.10–1.28) and a 13% higher risk of MRSA (HR 1.13; 95% CI 1.02–1.26) and acquired these infections earlier than non- Hispanic White children.[22] At a population level analysis by Freeman et al, the author found that proportion of African American residents were the strongest predictor of hospital-onset MRSA bloodstream infections in multivariable models [23]. Disparities in SSI was also found higher in African American demonstrating higher risk of SSI in orthopedic, vascular and gynecological surgical procedures [28].
These findings collectively indicate that racial disparities in HAIs reflect structural inequities in healthcare access, environmental exposure, diagnostic procedure and socioeconomic conditions rather than biological factors. A study by Sood and colleagues also found that when neighborhood deprivation was included in MRSA models, the previously observed racial disparities were no longer significant [24]. This suggests that the higher level of MRSA burden among Black patients may be driven by underlying structural inequalities rather than race itself.
Insurance Status
Insurance type was also one of the most consistent predictors of emerging HAI incidence and severity. In CDI, Medicaid-insured individuals experienced elevated risk: dual-eligible patients gad more than threefold higher incidence (3.1 times) compared to Medicare-only patients, and younger adults on Medicaid had 2.7 times higher CDI incidence than other private insurance types. Even among Medicaid beneficiaries without chronic comorbidities, CDI remained significantly higher (67.5 vs 45.6 per 100,00 person-years) [9].
Moreover, in VAP lack of insurance more than doubled the odds of mortality (aOR 2.13; 95% CI 1.49–3.06) than insured groups, suggesting the critical role of financial burden in acute infection outcomes [31]. Several surgical complication studies also indicate similar effects. Medicaid and Medicare were independently associated with higher SSI risk following abdominal surgery [26]. In cesarean deliveries, Medicaid coverage increases SSI risk by 40% (aOR 1.40; 95% CI 1.20–1.60), and Medicaid accounted for nearly half of all cesarean birth, highlighting substantial population-level implications [29]. Medicaid also reported higher odds of SSI-related readmission at both 30 and 90 days [30].
These findings indicate that insurance-based disparities reflect broader financial as well as socioeconomic burden, including delayed treatment, limited perioperative care and challenges with follow-up.
Poverty, Neighborhood Deprivation and Area- Level Social Disparities
Neighborhood-level indicators of deprivation were strongly and consistently associated with increased HAI risk and worse outcomes. Patients living in the most disadvantaged neighborhood had significantly higher CDI readmission rates (26% vs 21%), even after adjusting for comorbidities (aOR 1.16; 95% CI 1.04–1.28) [16]. Similarly, in pediatric care, children from low-income neighborhoods had significantly elevated CLABSI risk (RR 1.43; 95% CI 1.10–1.84) [19].
A study on MRSA risk also found that higher-deprivation neighborhood (ADI > 5) was linked to double the odds of MRSA infections (OR 2.26; 95%CI 1.14–4.45) [32], while state-level ecological analysis found that poverty, income inequality and the proportion of African American residents were all correlated with increased hospital-onset MRSA rates [23]. Conversely, higher community education levels and improved housing quality were associated with lower MRSA rates [21].
In surgical populations, pediatric patients in high SVI neighborhood had nearly 10-fold higher SSI rates (3.9% vs 0.4%), suggesting the profound impact of structural barriers such as overcrowded house, limited transportation and inadequate access to routine care [27].
These findings indicate that housing quality, income level and neighborhood significantly influence HAI risks across various infection types and healthcare settings.
Collectively all domains related to SDOH suggest the need for expanding infection prevention efforts beyond patient-level clinical factors and include social and structural determinants. Hence, this review has several strengths. It is first, to our knowledge, to systematically synthesize evidence across North America on the relationship between social determinants of health and a wide range of healthcare-associated infections, including MRSA, CLABSI, CAUTI, VAP and SSI. The review follows the structured PRISMA protocol to conduct this study and includes multiple large national datasets (e.g. NIS, Medicare, SPS) as well as hospital surveillance data. By integrating findings across diverse populations and infection types, the review highlights consistent and critical inequities among population. Furthermore, the narrative analysis allowed for the meaningful interpretation of heterogenous study designs, SDOH measures, contributing to valuable insights for infection prevention and health equity efforts.
Limitations
However, several limitations also exist in this study. First, the heterogeneity of study designs, data sources, HAI definitions and SDOH measures limited direct comparison and precluded meta-analysis. Many studies relied on administrative datasets, which may contain misclassification of both outcomes and social variables such as race or insurance type. Several studies also lack control of potential confounders, raising the possibility of potential residual confounding. Finally, this review was conducted by single author, there is potential risk of selection or interpretation bias despite adherence to a structured protocol.