John J. Engemann

Adverse Clinical and Economic Outcomes Attributable to Methicillin Resistance among Patients with Staphylococcus aureus Surgical Site Infection

Data for 479 patients were analyzed to assess the impact of methicillin resistance on the outcomes of patients with Staphylococcus aureus surgical site infections (SSIs). Patients infected with methicillin-resistant S. aureus (MRSA) had a greater 90-day mortality rate than did patients infected with methicillin-susceptible S. aureus (MSSA; adjusted odds ratio, 3.4; 95% confidence interval, 1.5-7.2). Patients infected with MRSA had a greater duration of hospitalization after infection (median additional days, 5; P<.001), although this was not significant on multivariate analysis (P=.11). Median hospital charges were 29,455 dollars for control subjects, 52,791 dollars for patients with MSSA SSI, and 92,363 dollars for patients with MRSA SSI (P<.001 for all group comparisons). Patients with MRSA SSI had a 1.19-fold increase in hospital charges (P=.03) and had mean attributable excess charges of 13,901 dollars per SSI compared with patients who had MSSA SSIs. Methicillin resistance is independently associated with increased mortality and hospital charges among patients with S. aureus SSI.

Use of Vancomycin or First-Generation Cephalosporins for the Treatment of Hemodialysis-Dependent Patients with Methicillin-Susceptible Staphylococcus aureus Bacteremia

BACKGROUND Because of its ease of dosing, vancomycin is commonly used to treat methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia in patients undergoing long-term hemodialysis. Clinical outcomes resulting from such a therapeutic strategy have not been well defined. METHODS We prospectively identified patients undergoing long-term hemodialysis who received a diagnosis of MSSA bacteremia. Clinical outcomes were grouped according to the predominant antibiotic received during their therapy (vancomycin or a first-generation cephalosporin [cefazolin]). Treatment failure (defined as death or recurrent infection) was determined at 12 weeks after the initial positive blood culture results. A multivariable analysis was used to adjust for confounders. RESULTS During an 84-month period, 123 hemodialysis-dependent patients with MSSA bacteremia were identified. Patients receiving vancomycin (n=77) tended to be younger (51 vs. 57 years; P=.06) and had a lower rates of metastatic complications at presentation (11.7% vs. 36.7%; P=.001) than did those receiving cefazolin (n=46). The 2 groups were similar with regard to Acute Physiology and Chronic Health Evaluation II scores, comorbidities, source of infection, type of hemodialysis access, and access removal rates. Treatment failure was more common among patients receiving vancomycin (31.2% vs. 13%; P=.02). In the multivariable analysis, factors independently associated with treatment failure included vancomycin use (odds ratio, 3.53; 95% confidence interval, 1.15-13.45) and retention of the hemodialysis access (odds ratio, 4.99; 95% confidence interval, 1.89-13.76). CONCLUSIONS Hemodialysis-dependent patients with MSSA bacteremia treated with vancomycin are at a higher risk of experiencing treatment failure than are those receiving cefazolin. In the absence of patient specific circumstances (e.g., allergy to beta-lactams), vancomycin should not be continued beyond empirical therapy for hemodialysis-dependent patients with MSSA bacteremia.

Early Predictors of In-Hospital Death in Infective Endocarditis

Background—Data on early determinants of outcome in infective endocarditis (IE) are limited. We evaluated the prognostic significance of early clinical characteristics in a large, prospective cohort of patients with IE. Methods and Results—Two hundred sixty-seven consecutive patients with definite or possible IE by modified Duke criteria and echocardiography performed within 7 days of presentation were evaluated. Acute physiology was assessed by the Acute Physiology, Age, Chronic Health Evaluation II (APACHE II) score at the time of presentation, and early heart failure was diagnosed by Framingham criteria. In-hospital mortality rate in the cohort was 19% and similar for patients with definite or possible IE (20% versus 16%, respectively; P =0.464). Independent predictors of death determined by logistic regression modeling were diabetes mellitus (OR 2.48; 95% CI, 1.24 to 4.96), Staphylococcus aureus as causative organism (OR, 2.06; 95% CI, 1.01 to 4.20), APACHE II score (OR, 1.07; 95% CI, 1.01 to 1.12), and embolic event (OR, 2.79; 95% CI, 1.15 to 6.80). Early echocardiographic findings of the Duke criteria were not predictive of death. Conclusions—Early in the course of IE, readily available clinical characteristics that reflect the host-pathogen interaction are predictive of in-hospital death. These factors may identify those patients with IE for more aggressive treatment.

Costs and outcomes among hemodialysis-dependent patients with methicillin-resistant or methicillin-susceptible Staphylococcus aureus bacteremia

OBJECTIVE Comorbid conditions have complicated previous analyses of the consequences of methicillin resistance for costs and outcomes of Staphylococcus aureus bacteremia. We compared costs and outcomes of methicillin resistance in patients with S. aureus bacteremia and a single chronic condition. DESIGN, SETTING, AND PATIENTS We conducted a prospective cohort study of hemodialysis-dependent patients with end-stage renal disease and S. aureus bacteremia hospitalized between July 1996 and August 2001. We used propensity scores to reduce bias when comparing patients with methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) S. aureus bacteremia. Outcome measures were resource use, direct medical costs, and clinical outcomes at 12 weeks after initial hospitalization. RESULTS Fifty-four patients (37.8%) had MRSA and 89 patients (62.2%) had MSSA. Compared with patients with MSSA bacteremia, patients with MRSA bacteremia were more likely to have acquired the infection while hospitalized for another condition (27.8% vs 12.4%; P = .02). To attribute all inpatient costs to S. aureus bacteremia, we limited the analysis to 105 patients admitted for suspected S. aureus bacteremia from a community setting. Adjusted costs were higher for MRSA bacteremia for the initial hospitalization (21,251 dollars vs 13,978 dollars; P = .012) and after 12 weeks (25,518 dollars vs 17,354 dollars; P = .015). At 12 weeks, patients with MRSA bacteremia were more likely to die (adjusted odds ratio, 5.4; 95% confidence interval, 1.5 to 18.7) than were patients with MSSA bacteremia. CONCLUSIONS Community-dwelling, hemodialysis-dependent patients hospitalized with MRSA bacteremia face a higher mortality risk, longer hospital stays, and higher inpatient costs than do patients with MSSA bacteremia.

Early Surgery in Patients with Infective Endocarditis: A Propensity Score Analysis

BACKGROUND An accurate assessment of the predictors of long-term mortality in patients with infective endocarditis is not possible using retrospective data because of inherent treatment biases and predictable imbalances in the distribution of prognostic factors. Largely because of these limitations, the role of surgery in long-term survival has not been adequately studied. METHODS Data were collected prospectively from 426 patients with infective endocarditis. Variables associated with surgery in patients who did not have intracardiac devices who had left-side-associated valvular infections were determined using multivariable analysis. Propensity scores were then assigned to each patient based on the likelihood of undergoing surgery. Using individual propensity scores, 51 patients who received medical and surgical treatment were matched with 51 patients who received medical treatment only. RESULTS The following factors were statistically associated with surgical therapy: age, transfer from an outside hospital, evidence of infective endocarditis on physical examination, the presence of infection with staphylococci, congestive heart failure, intracardiac abscess, and undergoing hemodialysis without a chronic catheter. After adjusting for surgical selection bias by propensity score matching, regression analysis of the matched cohorts revealed that surgery was associated with decreased mortality (hazard ratio, 0.27; 95% confidence interval, 0.13-0.55). A history of diabetes mellitus (hazard ratio, 4.81; 95% confidence interval, 2.41-9.62), the presence of chronic intravenous catheters at the beginning of the episode (hazard ratio, 2.65; 95% confidence interval, 1.31-5.33), and paravalvular complications (hazard ratio, 2.16; 95% confidence interval, 1.06-4.44) were independently associated with increased mortality. CONCLUSIONS Differences between clinical characteristics of patients with infective endocarditis who receive medical therapy versus patients who receive surgical and medical therapy are paramount. After controlling for inherent treatment selection bias and imbalances in prognostic factors using propensity score methodology, risk factors associated with increased long-term mortality included diabetes mellitus, the presence of a chronic catheter at the onset of infection, and paravalvular complications. In contrast, surgical therapy was associated with a significant long-term survival benefit.

Clinical outcomes and costs due to Staphylococcus aureus bacteremia among patients receiving long-term hemodialysis

OBJECTIVE To examine the clinical outcomes and costs associated with Staphylococcus aureus bacteremia among hemodialysis-dependent patients. DESIGN Prospectively identified cohort study. SETTING A tertiary-care university medical center in North Carolina. PATIENTS Two hundred ten hemodialysis-dependent adults with end-stage renal disease hospitalized with S. aureus bacteremia. RESULTS The majority of the patients (117; 55.7%) underwent dialysis via tunneled catheters, and 29.5% (62) underwent dialysis via synthetic arteriovenous fistulas. Vascular access was the suspected source of bacteremia in 185 patients (88.1%). Complications occurred in 31.0% (65), and the overall 12-week mortality rate was 19.0% (40). The mean cost of treating S. aureus bacteremia, including readmissions and outpatient costs, was

Surgical-site infection due to Staphylococcus aureus among elderly patients: Mortality, duration of hospitalization, and cost

24,034 per episode. The mean initial hospitalization cost was significantly greater for patients with complicated versus uncomplicated S. aureus bacteremia (

Reference Group Choice and Antibiotic Resistance Outcomes

32,462 vs

Risk Factors for Postoperative Mediastinitis Due to Methicillin-Resistant Staphylococcus aureus

17,011; P = .002). CONCLUSION Interventions to decrease the rate of S. aureus bacteremia are needed in this high-risk, hemodialysis-dependent population.

Predictors of mortality in patients with bloodstream infection due to ceftazidime-resistant Klebsiella pneumoniae.

OBJECTIVES To examine the impact of surgical-site infection (SSI) due to Staphylococcus aureus on mortality, duration of hospitalization, and hospital charges among elderly surgical patients and the impact of older age on these outcomes by comparing older and younger patients with S. aureus SSI. DESIGN A nested cohort study. SETTING A 750-bed, tertiary-care hospital and a 350-bed community hospital. PATIENTS Ninety-six elderly patients (70 years and older) with S. aureus SSI were compared with 2 reference groups: 59 uninfected elderly patients and 131 younger patients with S. aureus SSI. RESULTS Compared with uninfected elderly patients, elderly patients with S. aureus SSI were at risk for increased mortality (odds ratio [OR], 5.4; 95% confidence interval [CI95], 1.5-20.1), postoperative hospital-days (2.5-fold increase; CI95, 2.0-3.1), and hospital charges (2.0-fold increase; CI95, 1.7-2.4; dollar 41,117 mean attributable charges per SSI). Compared with younger patients with S. aureus SSI, elderly patients had increased mortality (adjusted OR, 2.9; CI95, 1.1-7.6), hospital-days (9 vs 13 days; P = .001), and median hospital charges (dollar 45,767 vs dollar 85,648; P < .001). CONCLUSIONS Among elderly surgical patients, S. aureus SSI was independently associated with increased mortality, hospital-days, and cost. In addition, being at least 70 years old was a predictor of death in patients with S. aureus SSI.