Michihiko Goto

Accuracy of Administrative Code Data for the Surveillance of Healthcare-Associated Infections: A Systematic Review and Meta-Analysis

Administrative code data (ACD), such as International Classifications of Diseases, Ninth Revision, Clinical Modification codes, are widely used in surveillance and public reporting programs that seek to identify healthcare-associated infections (HAIs); however, little is known about their accuracy. This systematic review summarizes evidence for the accuracy of ACD for the detection of selected HAIs, including catheter-associated urinary tract infection, Clostridium difficile infection (CDI), central line-associated bloodstream infection, ventilator-associated pneumonia/events, postprocedure pneumonia, methicillin-resistant Staphylococcus aureus, and surgical site infections (SSIs). We conducted meta-analysis for SSIs and CDIs, where acceptable numbers of primary studies were available. For these 2 conditions, ACD have moderate sensitivity and high specificity, but evidence for detection of other HAIs is limited. With current low prevalence of HAIs, the positive predictive value of ACD algorithms would be low. ACD may be inaccurate for detection of many HAIs and should be used cautiously for surveillance and reporting purposes.

Comparative Effectiveness of Beta-lactams versus Vancomycin for Treatment of Methicillin-Susceptible Staphylococcus aureus Bloodstream Infections among 122 Hospitals

BACKGROUND Previous studies indicate that vancomycin is inferior to beta-lactams for treatment of methicillin-susceptible Staphylococcus aureus (MSSA) bloodstream infections. However, it is unclear if this association is true for empiric and definitive therapy. Here, we compared beta-lactams with vancomycin for empiric and definitive therapy of MSSA bloodstream infections among patients admitted to 122 hospitals. METHODS This retrospective cohort study included all patients admitted to Veterans Affairs hospitals from 2003 to 2010 who had positive blood cultures for MSSA. Hazard ratios (HR) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression. Empiric therapy was defined as starting treatment 2 days before and up to 4 days after the first MSSA blood culture was collected. Definitive therapy was defined as starting treatment between 4 and 14 days after the first positive blood culture was collected. RESULTS Patients who received empiric therapy with a beta-lactam had similar mortality compared with those who received vancomycin (HR, 1.03; 95% CI, .89-1.20) after adjusting for other factors. However, patients who received definitive therapy with a beta-lactam had 35% lower mortality compared with patients who received vancomycin (HR, 0.65; 95% CI, .52-.80) after controlling for other factors. The hazard of mortality decreased further for patients who received cefazolin or antistaphylococcal penicillins compared with vancomycin (HR, 0.57; 95% CI, .46-.71). CONCLUSIONS For patients with MSSA bloodstream infections, beta-lactams are superior to vancomycin for definitive therapy but not for empiric treatment. Patients should receive beta-lactams for definitive therapy, specifically antistaphylococcal penicillins or cefazolin.

Comparative Effectiveness of Cefazolin Versus Nafcillin or Oxacillin for Treatment of Methicillin-Susceptible Staphylococcus aureus Infections Complicated by Bacteremia: A Nationwide Cohort Study

Background To treat patients with methicillin-susceptible Staphylococcus aureus (MSSA) infections, β-lactams are recommended for definitive therapy; however, the comparative effectiveness of individual β-lactams is unknown. This study compared definitive therapy with cefazolin vs nafcillin or oxacillin among patients with MSSA infections complicated by bacteremia. Methods This retrospective study included patients admitted to 119 Veterans Affairs hospitals from 2003 to 2010. Patients were included if they had a blood culture positive for MSSA and received definitive therapy with cefazolin, nafcillin, or oxacillin. Cox proportional hazards regression and ordinal logistic regression were used to identify associations between antibiotic therapy and mortality or recurrence. A recurrent infection was defined as a MSSA blood culture between 45 and 365 days after the first MSSA blood culture. Results Of 3167 patients, 1163 (37%) patients received definitive therapy with cefazolin. Patients who received cefazolin had a 37% reduction in 30-day mortality (hazard ratio [HR], 0.63; 95% confidence interval [CI], .51-.78) and a 23% reduction in 90-day mortality (HR, 0.77; 95% CI, .66-.90) compared with patients receiving nafcillin or oxacillin, after controlling for other factors. The odds of recurrence (odds ratio, 1.13; 95% CI, .94-1.36) were similar among patients who received cefazolin compared with patients who received nafcillin or oxacillin, after controlling for other factors. Conclusions In this large, multicenter study, patients who received cefazolin had a lower risk of mortality and similar odds of recurrent infections compared with nafcillin or oxacillin for MSSA infections complicated by bacteremia. Physicians might consider definitive therapy with cefazolin for these infections.

Association of Evidence-Based Care Processes With Mortality in Staphylococcus aureus Bacteremia at Veterans Health Administration Hospitals, 2003-2014

Importance Staphylococcus aureus bacteremia is common and frequently associated with poor outcomes. Evidence indicates that specific care processes are associated with improved outcomes for patients with S aureus bacteremia, including appropriate antibiotic prescribing, use of echocardiography to identify endocarditis, and consultation with infectious diseases (ID) specialists. Whether use of these care processes has increased in routine care for S aureus bacteremia or whether use of these processes has led to large-scale improvements in survival is unknown. Objective To examine the association of evidence-based care processes in routine care for S aureus bacteremia with mortality. Design, Setting, and Participants This retrospective observational cohort study examined all patients admitted to Veterans Health Administration (VHA) acute care hospitals who had a first episode of S aureus bacteremia from January 1, 2003, through December 31, 2014. Exposures Use of appropriate antibiotic therapy, echocardiography, and ID consultation. Main Outcomes and Measures Thirty-day all-cause mortality. Results Analyses included 36 868 patients in 124 hospitals (mean [SD] age, 66.4 [12.5] years; 36 036 [97.7%] male), including 19 325 (52.4%) with infection due to methicillin-resistant S aureus and 17 543 (47.6%) with infection due to methicillin-susceptible S aureus. Risk-adjusted mortality decreased from 23.5% (95% CI, 23.3%-23.8%) in 2003 to 18.2% (95% CI, 17.9%-18.5%) in 2014. Rates of appropriate antibiotic prescribing increased from 2467 (66.4%) to 1991 (78.9%), echocardiography from 1256 (33.8%) to 1837 (72.8%), and ID consultation from 1390 (37.4%) to 1717 (68.0%). After adjustment for patient characteristics, cohort year, and other care processes, receipt of care processes was associated with lower mortality, with adjusted odds ratios of 0.74 (95% CI, 0.68-0.79) for appropriate antibiotics, 0.73 (95% CI, 0.68-0.78) for echocardiography, and 0.61 (95% CI, 0.56-0.65) for ID consultation. Mortality decreased progressively as the number of care processes that a patient received increased (adjusted odds ratio for all 3 processes compared with none, 0.33; 95% CI, 0.30-0.36). An estimated 57.3% (95% CI, 48.4%-69.9%) of the decrease in mortality between 2003 and 2014 could be attributed to increased use of these evidence-based care processes. Conclusions and Relevance Mortality associated with S aureus bacteremia decreased significantly in VHA hospitals, and a substantial portion of the decreasing mortality may have been attributable to increased use of evidence-based care processes. The experience in VHA hospitals demonstrates that increasing application of these care processes may improve survival among patients with S aureus bacteremia in routine health care settings.

The Effect of a Nationwide Infection Control Program Expansion on Hospital-Onset Gram-Negative Rod Bacteremia in 130 Veterans Health Administration Medical Centers: An Interrupted Time-Series Analysis

BACKGROUND The Veterans Health Administration (VHA) introduced the Methicillin-Resistant Staphylococcus aureus (MRSA) Prevention Initiative in March 2007. Although the initiative has been perceived as a vertical intervention focusing on MRSA, it also expanded infection prevention and control programs and resources. We aimed to assess the horizontal effect of the initiative on hospital-onset (HO) gram-negative rod (GNR) bacteremia. METHODS This retrospective cohort included all patients who had HO bacteremia due to Escherichia coli, Klebsiella species, or Pseudomonas aeruginosa at 130 VHA facilities from January 2003 to December 2013. The effects were assessed using segmented linear regression with autoregressive error models, incorporating autocorrelation, immediate effect, and time before and after the initiative. Community-acquired (CA) bacteremia with same species was also analyzed as nonequivalent dependent controls. RESULTS A total of 11 196 patients experienced HO-GNR bacteremia during the study period. There was a significant change of slope in HO-GNR bacteremia incidence rates from before the initiative (+0.3%/month) to after (-0.4%/month) (P < .01), while CA GNR incidence rates did not significantly change (P = .08). Cumulative effect of the intervention on HO-GNR bacteremia incidence rates at the end of the study period was estimated to be -43.2% (95% confidence interval, -51.6% to -32.4%). Similar effects were observed in subgroup analyses of each species and antimicrobial susceptibility profile. CONCLUSIONS Within 130 VHA facilities, there was a sustained decline in HO-GNR bacteremia incidence rates after the implementation of the MRSA Prevention Initiative. As these organisms were not specifically targeted, it is likely that horizontal components of the initiative contributed to this decline.

Clinical Effectiveness of Mupirocin for Preventing Staphylococcus aureus Infections in Nonsurgical Settings: A Meta-analysis

A systematic literature review and meta-analysis was performed to identify effectiveness of mupirocin decolonization in prevention of Staphylococcus aureus infections, among nonsurgical settings. Of the 15 662 unique studies identified up to August 2015, 13 randomized controlled trials, 22 quasi-experimental studies, and 1 retrospective cohort study met the inclusion criteria. Studies were excluded if mupirocin was not used for decolonization, there was no control group, or the study was conducted in an outbreak setting. The crude risk ratios were pooled (cpRR) using a random-effects model. We observed substantial heterogeneity among included studies (I(2) = 80%). Mupirocin was observed to reduce the risk for S. aureus infections by 59% (cpRR, 0.41; 95% confidence interval [CI], .36-.48) and 40% (cpRR, 0.60; 95% CI, .46-.79) in both dialysis and nondialysis settings, respectively. Mupirocin decolonization was protective against S. aureus infections among both dialysis and adult intensive care patients. Future studies are needed in other settings such as long-term care and pediatrics.

Determination of risk factors for recurrent methicillin-resistant Staphylococcus aureus bacteremia in a Veterans Affairs healthcare system population.

OBJECTIVE To identify important risk factors for recurrent methicillin-resistant Staphylococcus aureus (MRSA) to assist clinicians in identifying high-risk patients for continued surveillance and follow-up. METHODS In this retrospective cohort study, we examined patients with MRSA bacteremia at 122 Veterans Affairs medical facilities from January 1, 2003, through December 31, 2010. Recurrent MRSA bacteremia was identified by a positive blood culture result from 2 to 180 days after index hospitalization discharge. Subset analyses were performed to evaluate risk factors for early-onset (2-60 days after discharge) and late-onset (61-180 days after discharge) recurrence. Risk factors were evaluated using Cox proportional hazards regression. RESULTS Of 18,425 patients, 1,159 (6.3%) had recurrent MRSA bacteremia. The median time to recurrence was 63 days. Longer duration of index bacteremia, increased severity of illness, receipt of only vancomycin, community-acquired infection, and several comorbidities were risk factors for recurrence. Congestive heart failure, hypertension, and rheumatoid arthritis/collagen disease were risk factors for early-onset but not late-onset recurrence. Geographic region and cardiac arrhythmias were risk factors for late-onset but not early-onset recurrence. CONCLUSIONS Risk factors for recurrent MRSA bacteremia included comorbidities, severity of illness, duration of bacteremia, and receipt of only vancomycin. Awareness of risk factors may be important at patient discharge for implementation of quality improvement initiatives including surveillance, follow-up, and education for high-risk patients.

Research Agenda for Antimicrobial Stewardship in the Veterans Health Administration

Author(s): Suda, Katie J; Livorsi, Daniel J; Goto, Michihiko; Forrest, Graeme N; Jones, Makoto M; Neuhauser, Melinda M; Hoff, Brian M; Ince, Dilek; Carrel, Margaret; Nair, Rajeshwari; Knobloch, Mary Jo; Goetz, Matthew B

Antimicrobial Nonsusceptibility of Gram-Negative Bloodstream Isolates, Veterans Health Administration System, United States, 2003–20131

Bacteremia caused by gram-negative bacteria is associated with serious illness and death, and emergence of antimicrobial drug resistance in these bacteria is a major concern. Using national microbiology and patient data for 2003–2013 from the US Veterans Health Administration, we characterized nonsusceptibility trends of community-acquired, community-onset; healthcare-associated, community-onset; and hospital-onset bacteremia for selected gram-negative bacteria (Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, and Acinetobacter spp.). For 47,746 episodes of bacteremia, the incidence rate was 6.37 episodes/10,000 person-years for community-onset bacteremia and 4.53 episodes/10,000 patient-days for hospital-onset bacteremia. For Klebsiella spp., P. aeruginosa, and Acinetobacter spp., we observed a decreasing proportion of nonsusceptibility across nearly all antimicrobial drug classes for patients with healthcare exposure; trends for community-acquired, community-onset isolates were stable or increasing. The role of infection control and antimicrobial stewardship efforts in inpatient settings in the decrease in drug resistance rates for hospital-onset isolates needs to be determined.

HIV Quality Report Cards: Impact of Case-Mix Adjustment and Statistical Methods

BACKGROUND There will be increasing pressure to publicly report and rank the performance of healthcare systems on human immunodeficiency virus (HIV) quality measures. To inform discussion of public reporting, we evaluated the influence of case-mix adjustment when ranking individual care systems on the viral control quality measure. METHODS We used data from the Veterans Health Administration (VHA) HIV Clinical Case Registry and administrative databases to estimate case-mix adjusted viral control for 91 local systems caring for 12 368 patients. We compared results using 2 adjustment methods, the observed-to-expected estimator and the risk-standardized ratio. RESULTS Overall, 10 913 patients (88.2%) achieved viral control (viral load ≤400 copies/mL). Prior to case-mix adjustment, system-level viral control ranged from 51% to 100%. Seventeen (19%) systems were labeled as low outliers (performance significantly below the overall mean) and 11 (12%) as high outliers. Adjustment for case mix (patient demographics, comorbidity, CD4 nadir, time on therapy, and income from VHA administrative databases) reduced the number of low outliers by approximately one-third, but results differed by method. The adjustment model had moderate discrimination (c statistic = 0.66), suggesting potential for unadjusted risk when using administrative data to measure case mix. CONCLUSIONS Case-mix adjustment affects rankings of care systems on the viral control quality measure. Given the sensitivity of rankings to selection of case-mix adjustment methods-and potential for unadjusted risk when using variables limited to current administrative databases-the HIV care community should explore optimal methods for case-mix adjustment before moving forward with public reporting.