Elaine Larson

Gender Differences in Risk of Bloodstream and Surgical Site Infections

BACKGROUNDIdentifying patients most at risk for hospital- and community-associated infections is one essential strategy for preventing infections.OBJECTIVETo investigate whether rates of community- and healthcare-associated bloodstream and surgical site infections varied by patient gender in a large cohort after controlling for a wide variety of possible confounders.DESIGNRetrospective cohort study.PARTICIPANTSAll patients discharged from January 1, 2006 through December 31, 2008 (133,756 adult discharges and 66,592 pediatric discharges) from a 650-bed tertiary care hospital, a 220-bed community hospital, and a 280-bed pediatric acute care hospital within a large, academic medical center in New York, NY.MAIN MEASURESData were collected retrospectively from various electronic sources shared by the hospitals and linked using patients’ unique medical record numbers. Infections were identified using previously validated computerized algorithms.KEY RESULTSOdds of community-associated bloodstream infections, healthcare-associated bloodstream infections, and surgical site infections were significantly lower for women than for men after controlling for present-on-admission patient characteristics and events during the hospital stay [odds ratios (95xa0% confidence intervals) were 0.85 (0.77–0.93), 0.82 (0.74–0.91), and 0.78 (0.68–0.91), respectively]. Gender differences were greatest for older adolescents (12–17xa0years) and adults 18–49xa0years and least for young children (<12xa0years) and older adults (≥70xa0years).CONCLUSIONSIn this cohort, men were at higher risk for bloodstream and surgical site infections, possibly due to differences in propensity for skin colonization or other anatomical differences.

Challenges Associated With Using Large Data Sets for Quality Assessment and Research in Clinical Settings

The rapidly expanding use of electronic records in health-care settings is generating unprecedented quantities of data available for clinical, epidemiological, and cost-effectiveness research. Several challenges are associated with using these data for clinical research, including issues surrounding access and information security, poor data quality, inconsistency of data within and across institutions, and a paucity of staff with expertise to manage and manipulate large clinical data sets. In this article, we describe our experience with assembling a data-mart and conducting clinical research using electronic data from four facilities within a single hospital network in New York City. We culled data from several electronic sources, including the institution’s admission-discharge-transfer system, cost accounting system, electronic health record, clinical data warehouse, and departmental records. The final data-mart contained information for more than 760,000 discharges occurring from 2006 through 2012. Using categories identified by the National Institutes of Health Big Data to Knowledge initiative as a framework, we outlined challenges encountered during the development and use of a domain-specific data-mart and recommend approaches to overcome these challenges.

Temporal trends and risk factors for extended-spectrum beta-lactamase-producing Escherichia coli in adults with catheter-associated urinary tract infections

BackgroundExtended-spectrum beta-lactamase (ESBL)-producing Escherichia coli cause up to 10% of catheter-associated urinary tract infections (CAUTI). We report changes in ESBL prevalence among CAUTIs in an adult acute care hospital from 2006-2012 and describe factors associated ESBL-production among E. coli CAUTI.FindingsData on patients ≥18xa0years discharged from a 647-bed tertiary/quaternary care hospital (2006-2012), a 221-bed community hospital (2007-2012), and a 914-bed tertiary/quaternary care hospital (2008) were obtained retrospectively from an electronic database (Nu2009=u2009415,430 discharges). Infections were identified using a previously validated electronic algorithm. Information on medical conditions and treatments were collected from electronic health records and discharge billing codes. A case-control design was used to determine factors associated with having a CAUTI caused by an ESBL-producing E. coli versus a non-ESBL-producing E. coli. Changes in yearly proportion of ESBL E. coli CAUTI at the 647-bed tertiary/quaternary care hospital were evaluated. ESBL increased from 4% in 2006 to 14% in 2012, peaking at 18% in 2009. Prior antibiotic treatment and urinary tract disease significantly increased odds of ESBL.ConclusionsThis study provides evidence that treatment with beta-lactam and non-beta-lactam antibiotics is a risk factor for acquiring ESBL-producing E. coli CAUTI, and the prevalence of this organism may be increasing in acute care hospitals.

Risk factors for hospital-acquired antimicrobial-resistant infection caused by Acinetobacter baumannii

BackgroundAcinetobacter baumannii can cause serious healthcare-associated infections (HAIs) and the incidence is increasing, with many strains now resistant to multiple antibiotic classes. The aims of this study were to examine factors associated with HAIs caused by antimicrobial-resistant as compared with antimicrobial-susceptible strains of A. baumannii and to investigate trends in the incidence of resistance over time. Electronic data from two U.S. hospitals in a large urban healthcare system in over the years 2006–2012 were used for the analysis. Multiple logistic regression was used to explore risk factors for infection with A. baumannii resistant to ampicillin or ampicillin/sulbactam in the bloodstream, urinary tract, and respiratory tract. The Cochran-Armitage trend test was used to explore resistance trends over time.FindingsA total of 671 adults with first-time A. baumannii infection were included in the analysis; 302 isolates (45xa0%) were resistant to ampicillin or ampicillin/sulbactam and 369 (55xa0%) were susceptible. In the multivariable analysis, significant risk factors included longer length of stay prior to infection (Odds Ratio [OR]u2009=u20091.03; 95xa0% Confidence Interval [CI]: 1.01, 1.04), hospital A versus B (ORu2009=u20090.35; 95xa0% CI: 0.13, 0.93), and antibiotic use prior to infection (ORu2009=u20092.88; 95xa0% CI: 1.02, 8.13). Resistance was more common in respiratory infections (ORu2009=u20092.96; 95xa0% CI: 1.04, 8.44). No trend was found between year of infection and resistance.ConclusionsThe risk factors we identified are consistent with previous findings, but we found no evidence in this population that resistance to ampicillin or ampicillin/sulbactam was increasing over time.

Prevalence and risk factors for antibiotic-resistant community-associated bloodstream infections

BACKGROUNDnAntibiotic resistance is increasing in many community settings. The purpose of this study was to determine the proportion of antibiotic resistant community-associated bloodstream infections (CA-BSIs) present on hospital admissions to identify risk factors for acquiring resistant versus susceptible CA-BSIs and to describe the incidence of concurrent infections with CA-BSIs.nnnMETHODSnWe conducted a retrospective cohort study of patients discharged from one community, one pediatric, and two tertiary/quaternary care hospitals within an academically affiliated network in the borough of Manhattan in New York, NY, from 2006 to 2008. The CA-BSIs present at hospital admission were defined as BSIs occurring within the first 48h of hospitalization. Infections and patient characteristics were identified using data available from patients electronic medical records and discharge records.nnnRESULTSnIn total, 1677 CA-BSIs were identified. Staphylococcus aureus had the largest proportion of resistance (41.2%), followed by enterococcal species (24.3%), Pseudomonas aeruginosa (20.2%), Streptococcus pneumoniae (16.6%), Acinetobacter baumannii (10.0%), and Klebsiella pneumoniae (9.9%). Significant predictors of resistance were prior residence in a skilled nursing facility (OR, 2.55; 95% CI, 1.39-4.70), advanced age (1.01; 1.002-1.02), presence of malignancy (0.58; 0.37-0.91), prior hospitalization (1.62; 1.17-2.23), a weighted Charlson score (1.09; 1.02-1.17) for S. aureus, presence of malignancy (1.82; 1.004-3.30), prior hospitalizations (2.03; 1.12-3.38) for enterococcal species, and younger age for S. pneumoniae (p=0.02). Urinary tract infections were the most common concurrent infection (n=45/87, 51.7%).nnnCONCLUSIONnOver 27% of the CA-BSIs present on admission were antibiotic resistant. Understanding the prevalence and risk factors for CA-BSIs may help improve empiric antibiotic therapy and outcomes for patients with community-onset infections.

Epidemiologic Associations Between Short-Bowel Syndrome and Bloodstream Infection Among Hospitalized Children

BACKGROUNDnChildren with short bowel syndrome (SBS) suffer from strikingly high rates of morbidity and mortality, due in part to their susceptibility to life-threatening infectious diseases. Few large, multisite studies have evaluated patient-specific factors associated with bacteremia in hospitalized children with and without SBS.nnnMETHODSnWe conducted a case-control study to examine the epidemiological associations between SBS and bloodstream infections (BSI) in hospitalized children. Pediatric BSI cases and controls were selected from a prospective cohort study conducted at 3 New York City hospitals.nnnRESULTSnAmong 40 723 hospital admissions of 30 179 children, 1047 diagnoses of BSI were identified. A total of 64 children had a diagnosis of SBS. BSI was identified frequently among hospitalizations for children admitted with SBS (n = 207/450, 46%) compared to hospitalizations for children without the condition (n = 840/40 273, 2.1%, P < .001). While this population represented only 0.2% of our overall cohort, it accounted for nearly 20% of all hospital admissions with BSI. Multivariable analysis identified 8 factors significantly associated with pediatric hospitalizations with BSI. These included a diagnosis of SBS (odds ratio [OR] 19.0), ages 1-5 years (OR 1.33), presence of a non-Broviac-Hickman central venous catheter (OR 6.36), immunosuppression (OR 0.53), kidney injury (OR 6.67), organ transplantation (OR 4.44), admission from a skilled nursing facility (OR 2.66), and cirrhosis (OR 7.23).nnnCONCLUSIONSnWhile several clinical characteristics are contributory to the risk of BSI in children, SBS remains the single strongest predictor. Further research into the mediators of this risk will be essential for the development of prevention strategies for this vulnerable population.

Carbapenem-Resistant Klebsiella pneumoniae Infection in Three New York City Hospitals Trended Downwards From 2006 to 2014

Background. Carbapenem-resistant Klebsiella pneumoniae (CRKP) infection is a rising public health threat since its first outbreaks in New York City (NYC) in the early 2000s. We investigated annual trends of CRKP infection in hospital-acquired infections (HAIs) and community-onset infections (COIs) treated in 3 NYC hospitals from 2006 to 2014. Methods. We extracted K pneumoniae infection data including carbapenem susceptibility and anatomical sites, compared clinical characteristics between CRKP and carbapenem-susceptible K pneumoniae infections, and determined CRKP infection proportions in total K pneumoniae infections in HAI and COI to identify statistically significant trends from 2006 to 2014 using the Cochran-Armitage trend test. Results. Carbapenem-resistant K pneumoniae contributed 17.3% (601 of 3477) of hospital-acquired K pneumoniae infection compared with 7.7% (149 of 1926) in COI from 2006 to 2014. Carbapenem-resistant K pneumoniae proportions in HAI and COI were positively correlated over time (r = 0.83, P < .01), and there were downward annual trends of CRKP proportions from 2006 to 2014 in both HAI and COI (25.8% to 10.5% in HAI, P < .001; 13.6% to 3.1% in COI, P < .001). By anatomical site, significant downward annual trends were present only in urinary tract infection (P < .001 for both HAI and COI) from 2006 to 2014. Conclusions. Annual trends of CRKP proportions from 2006 to 2014 were downward in both HAI and COI, and HAI and COI were positively correlated. Efforts to reduce and prevent CRKP infections in both hospital and community settings were successful and warrant continuation.

Temporal trends and risk factors for healthcare-associated vancomycin-resistant enterococci in adults

BACKGROUNDnPublished data regarding temporal trends in vancomycin-resistant enterococci (VRE) prevalence within specific regions or healthcare systems are scarce.nnnAIMnTo characterize temporal trends and risk factors for healthcare-associated infections caused by VRE.nnnMETHODSnThe study included all adult discharges occurring from 2006 to 2014 with an enterococcal infection from three hospitals in a large academic healthcare system. Bivariate analyses were used to identify statistically significant factors associated with vancomycin-susceptible or -resistant infection. Statistically significant variables were included in a final logistic regression model. Trends assessed whether the proportion of enterococcal infections resistant to vancomycin changed over time.nnnFINDINGSnThe sample included 10,186 adults with first-time healthcare-associated enterococcal infection. Significant risk factors (P≤0.05) for VRE in the final logistic regression model included: tertiary 1 hospital, intensive care unit length of stay, higher Charlson Comorbidity Index, previous immunosuppressive or chemotherapeutic medications, previous hospitalization, renal failure, malignancy, longer length of stay prior to infection, taking an antibiotic prior to infection, being female, and having an infection in winter or spring. Between 2006 and 2014, the rate of resistance varied from 37.1 to 42.9% but there were no significant differences in the proportion resistant to vancomycin over time (P=0.36).nnnCONCLUSIONnResearch targeted at risk factors is important to decrease the amount of VRE infections.

Utility of Electronic Medical Records to Assess the Relationship Between Parenteral Nutrition and Central Line–Associated Bloodstream Infections in Adult Hospitalized Patients

BACKGROUNDnParenteral nutrition is associated with increased central line-associated bloodstream infections (CLABSIs). Electronic databases are important for identifying independent risk factors for prevention strategies. Our aims were to evaluate the utility of using electronic data sources to identify risk factors for CLABSIs, including parenteral nutrition (PN), and to assess the association between CLABSI and PN administration.nnnMETHODSnData were obtained for all discharges of adult patients in whom a central line was inserted between September 1, 2007, and December 31, 2008, in a large, academically affiliated hospital in New York City. CLABSI was defined electronically using a modified definition from the Centers for Disease Control and Prevention. A manual chart review was also undertaken to assess validity/reliability of the electronic database and gather additional information. Risk factors for CLABSI were examined using logistic regression.nnnRESULTSnAmong 4840 patients, there were 220 CLABSIs, an incidence of 5.4 CLABSIs per 1000 central line days. Risk factors included PN (odds ratio [OR], 4.33; 95% confidence interval [CI], 2.50-7.48), intensive care unit stay (OR, 2.26; 95% CI, 1.58-3.23), renal disease (OR, 2.79; 95% CI, 2.00-3.88), and immunodeficiency (OR, 2.26; 95% CI, 1.70-3.00). Diabetes mellitus was associated with reduced CLABSI rates (OR, 0.63; 95% CI, 0.45-0.88).nnnCONCLUSIONSnThe utility of electronic medical records for determining risk factors is limited by such things as free-text data entry. Using a hybrid between fully electronic and manual chart review, reliable data were obtained. PN is associated with a high risk for CLABSI in a population highly selected for indications for PN.

Incidence and risk factors for community-associated methicillin-resistant Staphylococcus aureus in New York City, 2006–2012

This study aims to describe changes in incidence and risk factors for community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) infections upon admission to two New York City hospitals from 2006 to 2012. We examined the first hospitalization for adult patients using electronic health record and administrative data and determined the annual incidence/1000 admissions of total S. aureus, total MRSA, and CA-MRSA (within 48 h of admission) in clinical specimens over the study period. Logistic regression was used to identify factors associated with CA-MRSA in 2006 and 2012. In 137 350 admissions, the incidence of S. aureus, MRSA, and CA-MRSA/1000 admissions were 15·6, 7·0, and 3·5, respectively. The total S. aureus and MRSA isolations decreased significantly over the study period (27% and 25%, respectively) while CA-MRSA incidence was unchanged. CA-MRSA increased as a proportion of all MRSA between 2006 (46%) and 2012 (62%), and was most frequently isolated from respiratory (1·5/1000) and blood (0·7/1000) cultures. Logistic regression analysis of factors associated with isolation of CA-MRSA showed that age ⩾65 years [odds ratio (OR) 2·3, 95% confidence interval (CI) 1·2-4·5], male gender (OR 1·8, 95% CI 1·2-2·8) and history of renal failure (OR 2·6, 95% CI 1·6-4·2) were significant predictors of infection in 2006. No predictors were identified in 2012.