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.

The economic impact of Staphylococcus aureus infection in New York City hospitals

We modeled estimates of the incidence, deaths, and direct medical costs of Staphylococcus aureus infections in hospitalized patients in the New York City metropolitan area in 1995 by using hospital discharge data collected by the New York State Department of Health and standard sources for the costs of health care. We also examined the relative impact of methicillin-resistant versus -sensitive strains of S. aureus and of community-acquired versus nosocomial infections. S. aureus-associated hospitalizations resulted in approximately twice the length of stay, deaths, and medical costs of typical hospitalizations; methicillin-resistant and -sensitive infections had similar direct medical costs, but resistant infections caused more deaths (21% versus 8%). Community-acquired and nosocomial infections had similar death rates, but community-acquired infections appeared to have increased direct medical costs per patient ($35,300 versus $28,800). The results of our study indicate that reducing the incidence of methicillin-resistant and -sensitive nosocomial infections would reduce the societal costs of S. aureus infection.

Continuous versus intermittent infusion of vancomycin in severe Staphylococcal infections: prospective multicenter randomized study

A continuous infusion of vancomycin (CIV) may provide an alternative mode of infusion in severe hospital-acquired methicillin-resistant staphylococcal (MRS) infections. A multicenter, prospective, randomized study was designed to compare CIV (targeted plateau drug serum concentrations of 20 to 25 mg/liter) and intermittent infusions of vancomycin (IIV; targeted trough drug serum concentrations of 10 to 15 mg/liter) in 119 critically ill patients with MRS infections (bacteremic infections, 35%; pneumonia, 45%). Microbiological and clinical outcomes, safety, pharmacokinetics, ease of treatment adjustment, and cost were compared. Microbiological and clinical outcomes and safety were similar. CIV patients reached the targeted concentrations faster (36 +/- 31 versus 51 +/- 39 h, P = 0.029) and fewer samples were required for treatment monitoring than with IIV patients (7.7 +/- 2.2 versus 11.8 +/- 3.9 per treatment, P < 0.0001). The variability between patients in both the area under the serum concentration-time curve (AUC(24h)) and the daily dose given over 10 days of treatment was lower with CIV than with IIV (variances, 14,621 versus 53,975 mg(2)/liter(2)/h(2) [P = 0.026] and 414 versus 818 g(2) [P = 0.057], respectively). The 10-day treatment cost per patient was $454 +/- 137 in the IIV group and was 23% lower in the CIV group ($321 +/- 81: P < 0.0001). In summary, for comparable efficacy and tolerance, CIV may be a cost-effective alternative to IIV.

Control of endemic methicillin-resistant Staphylococcus aureus: a cost-benefit analysis in an intensive care unit

CONTEXT

Despite the success of some countries in controlling endemic methicillin-resistant Staphylococcus aureus (MRSA), such programs have not been implemented for some hospitals with endemic infection because of concerns that these programs would be costly and of limited benefit.

OBJECTIVE

To compare the costs and benefits of an MRSA control program in an endemic setting.

DESIGN AND SETTING

Case-control study conducted at a medical intensive care unit (ICU) of a French university hospital with a 4% prevalence of MRSA carriage at ICU admission.

PATIENTS

Twenty-seven randomly selected patients who had ICU-acquired MRSA infection between January 1993 and June 1997, matched to 27 controls hospitalized during the same period without MRSA infection.

MAIN OUTCOME MEASURES

Intensive care unit costs attributable to MRSA infection, computed from excess therapeutic intensity in cases using estimates from a cost model derived in the same ICU, were compared with costs of the control program, derived from time-motion study of nurses and physicians. The threshold for MRSA carriage that would make the control strategy dominant was determined; sensitivity analyses varied rates of MRSA transmission and ratio of infection to transmission, length of ICU stay, and costs of isolation precautions.

RESULTS

The mean cost attributable to MRSA infection was US $9275 (median, $5885; interquartile range, $1400-$16,720). Total costs of the control program ranged from $340 to $1480 per patient. A 14% reduction in MRSA infection rate resulted in the control program being beneficial. In sensitivity analyses, the control strategy was dominant for a prevalence of MRSA carriage on ICU admission ranging from 1% to 7%, depending on costs of control measures and MRSA transmission, for infection rates greater than 50% following transmission.

CONCLUSIONS

In this example of a hospital with endemic MRSA infection, selective screening and isolation of carriers on ICU admission are beneficial compared with no isolation.

Health and economic impacts of antimicrobial resistance

For comparison of the impacts of infections due to antimicrobial-resistant bacteria with those of infections due to antimicrobial-susceptible strains of the same bacteria, data were evaluated from 175 published and unpublished reports of investigations of nosocomial and community-acquired infections with selected bacteria. The evaluation of outcomes of hospital-acquired infections with resistant organisms was often confounded by risk factors also associated with poor outcomes. Nevertheless, for both nosocomial and community-acquired infections, the mortality, the likelihood of hospitalization, and the length of hospital stay were usually at least twice as great for patients infected with drug-resistant strains as for those infected with drug-susceptible strains of the same bacteria. Poor outcomes could be attributed both to the expected effects of ineffective antimicrobial therapy and to the unexpected occurrence of drug-resistant infections complicated by prior antimicrobial therapy for other medical problems. Although the adverse economic and health effects of drug-resistant bacterial infections can only be roughly quantified, it is concluded that antimicrobial resistance is an important health problem and an economic burden to society.

Nosocomial methicillin-resistant and methicillin-susceptible Staphylococcus aureus primary bacteremia: at what costs?

OBJECTIVE

To determine the attributable hospital stay and costs for nosocomial methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) primary bloodstream infections (BSIs).

DESIGN

Pairwise-matched (1:1) nested case-control study.

SETTING

University-based tertiary-care medical center.

PATIENTS

Patients admitted between December 1993 and March 1995 were eligible. Cases were defined as patients with a primary nosocomial S. aureus BSI; controls were selected according to a priori matching criteria.

MEASUREMENTS

Length of hospital stay and total and variable direct costs of hospitalization.

RESULTS

The median hospital stay attributable to primary nosocomial MSSA BSI was 4 days, compared with 12 days for MRSA (P=.023). Attributable median total cost for MSSA primary nosocomial BSIs was $9,661 versus $27,083 for MRSA nosocomial infections (P=.043).

CONCLUSION

Nosocomial primary BSI due to S. aureus significantly prolongs the hospital stay. Primary nosocomial BSIs due to MRSA result in an approximate threefold increase in direct cost, compared with those due to MSSA.

The Burden of Staphylococcus aureus Infections on Hospitals in the United States

BACKGROUND

Previous studies have investigated the impact of Staphylococcus aureus infections on individual hospitals, but to date, no study using nationally representative data has estimated this burden.

METHODS

This is a retrospective analysis of the 2000 and 2001 editions of the Agency for Healthcare Research and Quality's Nationwide Inpatient Sample database, which represents a stratified 20% sample of hospitals in the United States. All inpatient discharge data from 994 hospitals in 28 states during 2000 and from 986 hospitals in 33 states during 2001, representing approximately 14 million inpatient stays, were analyzed to determine the association of S aureus infections with length of stay, total charges, and in-hospital mortality.

RESULTS

Staphylococcus aureus infection was reported as a discharge diagnosis for 0.8% of all hospital inpatients, or 292 045 stays per year. Inpatients with S aureus infection had, on average, 3 times the length of hospital stay (14.3 vs 4.5 days; P<.001), 3 times the total charges (48,824 US dollars vs 14,141 US dollars; P<.001), and 5 times the risk of in-hospital death (11.2% vs 2.3%; P<.001) than inpatients without this infection. Even when controlling for hospital fixed effects and for patient differences in diagnosis-related groups, age, sex, race, and comorbidities, the differences in mean length of stay, total charges, and mortality were significantly higher for hospitalizations associated with S aureus.

CONCLUSIONS

Staphylococcus aureus infections represent a considerable burden to US hospitals, particularly among high-risk patient populations. The potential benefits to hospitals in terms of reduced use of resources and costs as well as improved outcomes from preventing S aureus infections are significant.

The clinical and economic impact of deep chest surgical site infections following coronary artery bypass graft surgery

STUDY OBJECTIVES

To examine how deep chest surgical site infections following coronary artery bypass graft (CABG) surgery impact hospital inpatient length of stay (LOS), costs, and mortality.

SETTING

A large, Midwestern community medical center.

DESIGN

All CABG patients who developed deep chest infection (n = 41) were compared to a set of control subjects (n = 160) systematically selected as every tenth uninfected CABG patient. Clinical data were abstracted from patient records, and cost information was obtained from the cost accounting database of the hospital.

RESULTS

Variables that significantly increased the risk of deep chest surgical site infection included obesity (odds ratio [OR], 11; p = 0. 0001), renal insufficiency (OR, 8.9; p = 0.0001), connective tissue disease (OR, 25.4; p = 0.0003), reexploration for bleeding (OR, 8.2; p = 0.0015), and the timing of antibiotic prophylaxis (> 60 min before incision; OR, 5.3; p = 0.0128). Within 1 year postoperatively, patients with deep chest surgical site infection had a mortality rate of 22%, vs 0.6% for uninfected patients (p = 0.0001). Infected patients also incurred an average of 20 additional hospital days (p = 0.0001). Univariate analysis indicated that patients who developed deep chest surgical site infection incurred $20,012 in additional costs in the first year (p = 0.0001). Infected patients who died incurred on average $60,547 more than infected patients who survived (p = 0.034). Multivariate analysis confirmed the magnitude of the estimate of the cost for deep chest surgical site infection ($18, 938; p = 0.0001).

CONCLUSIONS

Deep chest surgical site infections following CABG surgery are associated with significant increases in LOS, hospitalization costs, and mortality. These results suggest the need for improved infection control measures to reduce deep chest surgical site infection rates.

Costs and Outcomes Among Hemodialysis-Dependent Patients With Methicillin-Resistant or Methicillin-SusceptibleStaphylococcus aureusBacteremia

Objective:

Comorbid conditions have complicated previous analyses of the consequences of methicillin resistance for costs and outcomes ofStaphylococcus aureusbacteremia. We compared costs and outcomes of methicillin resistance in patients withS. aureusbacteremia and a single chronic condition.

Design, Setting, and Patients:

We conducted a prospective cohort study of hemodialysis-dependent patients with end-stage renal disease andS. aureusbacteremia 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. aureusbacteremia. 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 toS. aureusbacteremia, we limited the analysis to 105 patients admitted for suspectedS. aureusbacteremia from a community setting. Adjusted costs were higher for MRSA bacteremia for the initial hospitalization ($21,251 vs $13,978;P= .012) and after 12 weeks ($25,518 vs $17,354;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.

The economic impact of methicillin-resistant Staphylococcus aureus in Canadian hospitals

OBJECTIVES

To determine the costs associated with the management of hospitalized patients with methicillin-resistant Staphylococcus aureus (MRSA), and to estimate the economic burden associated with MRSA in Canadian hospitals.

DESIGN

Patient-specific costs were used to determine the attributable cost of MRSA associated with excess hospitalization and concurrent treatment. Excess hospitalization for infected patients was identified using the Appropriateness Evaluation Protocol, a criterion-based chart review process to determine the need for each day of hospitalization. Concurrent treatment costs were identified through chart review for days in isolation, antimicrobial therapy, and MRSA screening tests. The economic burden to Canadian hospitals was estimated based on 3,167,521 hospital discharges for 1996 and 1997 and an incidence of 4.12 MRSA cases per 1,000 admissions.

SETTING

A tertiary-care, university-affiliated teaching hospital in Toronto, Ontario, Canada.

PATIENTS

Inpatients with at least one culture yielding MRSA between April 1996 and March 1998.

RESULTS

A total of 20 patients with MRSA infections and 79 colonized patients (with 94 admissions) were identified. This represented a rate of 2.9 MRSA cases per 1,000 admissions. The mean number of additional hospital days attributable to MRSA infection was 14, with 11 admissions having at least 1 attributable day. The total attributable cost to treat MRSA infections was $287,200, or $14,360 per patient The cost for isolation and management of colonized patients was $128,095, or $1,363 per admission. Costs for MRSA screening in the hospital were $109,813. Assuming an infection rate of 10% to 20%, we determined the costs associated with MRSA in Canadian hospitals to be $42 million to $59 million annually.

CONCLUSIONS

These results indicate that there is a substantial economic burden associated with MRSA in Canadian hospitals. These costs will continue to rise if the incidence of MRSA increases further.

Clinical effectiveness and cost-effectiveness of 2 management strategies for infected total hip arthroplasty in the elderly

Optimal management of infected total hip arthroplasty poses a major challenge to clinicians. Exchange arthroplasty is usually advocated but has high rates of surgical morbidity and is expensive. Debridement with prosthesis retention is associated with less morbidity, but high rates of relapsed infection have been described. To estimate the effectiveness and cost-effectiveness of these 2 strategies among older patients, we used a Markov model to simulate patients' projected lifetime clinical course in hypothetical cohorts of 65-year-old and frail 80-year-old men and women. Initial debridement and retention increased life expectancy 2.2-2.6 quality-adjusted life months and had a favorable cost-effectiveness ratio in all cohorts. Results were most sensitive to the annual rate of relapse after debridement and age at initial diagnosis of infection. In the absence of prospective clinical trials, debridement and retention is a reasonable strategy for treatment of older persons with staphylococcal or streptococcal infection and a nonloosened prosthesis.

A systematic audit of economic evidence linking nosocomial infections and infection control interventions: 1990-2000

BACKGROUND

Nosocomial infections (NIs) are a serious patient safety issue. Infection control personnel are responsible for implementing interventions to reduce this risk. The purpose of this systematic review was to audit the published economic evidence of the attributable cost of NIs and interventions conducted by infection control professionals and to evaluate the methods used. Economic evaluation methodology and recommendations for standardization are reviewed.

METHODS

A search of MEDLINE and HealthSTAR with medical subject headings or text words "nosocomial infections," "infection control," or "hospital acquired infections" cross-referenced with "costs," "cost analysis," "economics," or "cost-effectiveness analysis" was conducted. Published review articles were also searched. Inclusion criteria included articles published between 1990 and 2000 that contained an abstract and original cost estimate and were written in English. Results were standardized into a common currency.

RESULTS

Fifty-five studies were eligible. Approximately one quarter examined NIs in intensive care patients (n = 13). Most studies were conducted from the hospital perspective (n = 48). The costs attributable to bloodstream (mean = $38,703) and methicillin-resistant Staphylococcus aureus infections (mean = $35,367) were the largest.

CONCLUSIONS

Increased standardization and rigor are needed. Clinicians should partner with economists and policy analysts to expand and improve the economic evidence available to reduce hospital complications such as NI and other adverse patient/staff outcomes.

Clinical and financial outcomes due to methicillin resistant Staphylococcus aureus surgical site infection: a multi-center matched outcomes study

BACKGROUND

The clinical and financial outcomes of SSIs directly attributable to MRSA and methicillin-resistance are largely uncharacterized. Previously published data have provided conflicting conclusions.

METHODOLOGY

We conducted a multi-center matched outcomes study of 659 surgical patients. Patients with SSI due to MRSA were compared with two groups: matched uninfected control patients and patients with SSI due to MSSA. Four outcomes were analyzed for the 90-day period following diagnosis of the SSI: mortality, readmission, duration of hospitalization, and hospital charges. Attributable outcomes were determined by logistic and linear regression.

PRINCIPAL FINDINGS

In total, 150 patients with SSI due to MRSA were compared to 231 uninfected controls and 128 patients with SSI due to MSSA. SSI due to MRSA was independently predictive of readmission within 90 days (OR = 35.0, 95% CI 17.3-70.7), death within 90 days (OR = 7.27, 95% CI 2.83-18.7), and led to 23 days (95% CI 19.7-26.3) of additional hospitalization and $61,681 (95% 23,352-100,011) of additional charges compared with uninfected controls. Methicillin-resistance was not independently associated with increased mortality (OR = 1.72, 95% CI 0.70-4.20) nor likelihood of readmission (OR = 0.43, 95% CI 0.21-0.89) but was associated with 5.5 days (95% CI 1.97-9.11) of additional hospitalization and $24,113 (95% 4,521-43,704) of additional charges.

CONCLUSIONS/SIGNIFICANCE

The attributable impact of S. aureus and methicillin-resistance on outcomes of surgical patients is substantial. Preventing a single case of SSI due to MRSA can save hospitals as much as $60,000.

Clinical and economic impact of methicillin resistance in patients with Staphylococcus aureus bacteremia

We performed a retrospective cohort study to determine the morbidity, mortality, and hospital costs attributable to methicillin resistance in patients with S. aureus bacteremia (SAB). Episodes of SAB occurring at the Detroit Receiving Hospital in 1999-2001 were evaluated. Controlling for confounding variables, patients with methicillin-resistant Staphylococcus aureus (MRSA) had a 1.5-fold longer length of stay (19.1 versus 14.2 days, P = 0.005) and a 2-fold increased cost of hospitalization (dollar 21577 versus dollar 11668, P = 0.001) compared with methicillin-susceptible S. aureus (MSSA). MRSA patients were at increased risk for delayed treatment, and delayed therapy was an independent predictor of mortality. Efforts should be made to ensure that appropriate therapy is initiated promptly in patients at risk for MRSA. Infection control policies must be strictly enforced to limit the spread of MRSA and potentially minimize excess hospital expenditures incurred with MRSA. With the advent of new treatment options, the impact of MRSA will need to be revisited to determine if these therapies can remedy the increased morbidity associated with MRSA.

Systematic review of isolation policies in the hospital management of methicillin-resistant Staphylococcus aureus: a review of the literature with epidemiological and economic modelling

OBJECTIVE

To review the evidence for the effectiveness of different isolation policies and screening practices in reducing the incidence of methicillin-resistant Staphylococcus aureus (MRSA) colonisation and infection in hospital in-patients. To develop transmission models to study the effectiveness and cost-effectiveness of isolation policies in controlling MRSA.

DATA SOURCES

MEDLINE, EMBASE, CINAHL, The Cochrane Library and SIGLE (1966-2000). Hand-searching key journals. No language restrictions.

REVIEW METHODS

Key data were extracted from articles reporting MRSA-related outcomes and describing an isolation policy in a hospital with epidemic or endemic MRSA. No quality restrictions were imposed on studies using isolation wards (IW) or nurse cohorting (NC). Other studies were included if they were prospective or employed planned comparisons of retrospective data. Stochastic and deterministic models investigated long-term transmission dynamics, studying the effect of a fixed capacity IW, producing economic evaluations using local cost data.

RESULTS

A total of 46 studies were accepted: 18 IWs, 9 NC, 19 other isolation policies. Most were interrupted time series, with few planned formal prospective studies. All but one reported multiple interventions. Consideration of potential confounders, measures to prevent bias, and appropriate statistical analysis were mostly lacking. No conclusions could be drawn in a third of studies. Most others provided evidence consistent with reduction of MRSA acquisition. Six long interrupted time series provided the strongest evidence. Four of these provided evidence that intensive control measures which included patient isolation were effective in controlling MRSA. In two others IW use failed to prevent endemic MRSA. There was no robust economic evaluation. Models showed that improving the detection rate or ensuring adequate isolation capacity reduced endemic levels, with substantial savings achievable.

CONCLUSIONS

Major methodological weaknesses and inadequate reporting in published research mean that many plausible alternative explanations for reductions in MRSA acquisition associated with interventions cannot be excluded. No well-designed studies allow the role of isolation measures alone to be assessed. Nonetheless, there is evidence that concerted efforts that include isolation can reduce MRSA even when endemic. Little evidence was found to suggest that current isolation measures recommended in the UK are ineffective, and these should continue to be applied until further research establishes otherwise. The studies with the strongest evidence, together with the results of the modelling, provide testable hypotheses for future research. Guidelines to facilitate design of future research are produced.

Cost-effectiveness of active surveillance cultures and contact/droplet precautions for control of methicillin-resistant Staphylococcus aureus

Some have reported that adopting Centers for Disease Control and Prevention guidelines requiring contact precautions for methicillin-resistant Staphylococcus aureus (MRSA) had no impact on rates of nosocomial spread or infection, and may therefore waste money. The objective of the present study was to evaluate the cost-effectiveness of active surveillance cultures and barrier precautions for controlling MRSA. Estimated costs of surveillance cultures and isolation measures used during an MRSA outbreak at this hospital were compared with the estimated attributable excess costs of methicillin resistance (i.e., the difference between MRSA and methicillin-sensitive S. aureus costs) for bacteraemias occurring during an MRSA outbreak not promptly controlled at another hospital. The study was set in the neonatal intensive care units of two tertiary care hospitals. Estimated costs of controlling the 10.5-month outbreak in this neonatal intensive care unit that resulted in 18 colonized and four infected infants ranged from $48 617 to $68 637. The estimated attributable excess cost of 75 MRSA bacteraemias in a second neonatal intensive care unit outbreak that resulted in 14 deaths and lasted 51 months was $1 306 600. Weekly active surveillance cultures and isolation of patients with MRSA halted an outbreak at this hospital, and cost 19- to 27-fold less than the attributable costs of MRSA bacteraemias in another outbreak that was not promptly controlled. The costs of infections at other body sites and the human cost of deaths from infection were not estimated but would further help to justify the cost of identifying colonized patients and implementing effective preventive measures.

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 $24,034 per episode. The mean initial hospitalization cost was significantly greater for patients with complicated versus uncomplicated S. aureus bacteremia ($32,462 vs $17,011; P = .002).

CONCLUSION

Interventions to decrease the rate of S. aureus bacteremia are needed in this high-risk, hemodialysis-dependent population.

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

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.

Clinical and Economic Analysis of Methicillin-Susceptible and -Resistant Staphylococcus aureus Infections

BACKGROUND:

The rate of methicillin-resistant Staphylococcus aureus (MRSA) has increased significantly over the last decade. Previous cohort studies of patients with MRSA bacteremia have reported higher mortality rates, increased morbidity, longer hospital length of stay (LOS), and higher costs compared with patients with methicillin-susceptible S. aureus (MSSA) bacteremia. The clinical and economic impact of MRSA involving other sites of infection has not been well characterized.

OBJECTIVE:

To determine the clinical and economic implications of MRSA compared with MSSA infections across a variety of infection sites and severity of illnesses.

METHODS:

A retrospective, case—control analysis comparing differences in clinical and economic outcomes of patients with MRSA and MSSA infections was conducted at an academic medical center. Case patients with MRSA infection were matched (1:1 ratio) to control patients with MSSA infection according to age, site of infection, and type of care.

RESULTS:

Thirty-six matched pairs of patients with S. aureus infection were identified. Baseline characteristics of patients with MSSA and MRSA infection were similar. Patients with MRSA infections had a trend toward longer hospital LOS (15.5 vs 11 days; p = 0.05) and longer antibiotic-related LOS (10 vs 7 days; p = 0.003). Median hospital cost associated with treatment of patients with MRSA infections was higher compared with patients with MSSA infections ($16 575 vs $12 862; p = 0.11); however, this difference was not statistically significant. Treatment failure was common in patients with MRSA infection. Among patients with MSSA infections, treatment failure was associated with vancomycin use.

CONCLUSIONS:

Patients with MRSA infections had worse clinical and economic outcomes compared with patients with MSSA infections.

Surgical site infections: Causative pathogens and associated outcomes

BACKGROUND

Surgical site infections (SSIs) are associated with substantial morbidity, mortality, and cost. Few studies have examined the causative pathogens, mortality, and economic burden among patients rehospitalized for SSIs.

METHODS

From 2003 to 2007, 8302 patients were readmitted to 97 US hospitals with a culture-confirmed SSI. We analyzed the causative pathogens and their associations with in-hospital mortality, length of stay (LOS), and cost.

RESULTS

The proportion of methicillin-resistant Staphylococcus aureus (MRSA) significantly increased among culture-positive SSI patients during the study period (16.1% to 20.6%, respectively, P < .0001). MRSA (compared with other) infections had higher raw mortality rates (1.4% vs 0.8%, respectively, P=.03), longer LOS (median, 6 vs 5 days, respectively, P < .0001), and higher hospital costs ($7036 vs $6134, respectively, P < .0001). The MRSA infection risk-adjusted attributable LOS increase was 0.93 days (95% confidence interval [CI]: 0.65-1.21; P < .0001), and cost increase was $1157 (95% CI: $641-$1644; P < .0001). Other significant independent risk factors increasing cost and LOS included illness severity, transfer from another health care facility, previous admission (<30 days), and other polymicrobial infections (P < .05).

CONCLUSION

SSIs caused by MRSA increased significantly and were independently associated with economic burden. Admission illness severity, transfer from another health care setting, and recent hospitalization were associated with higher mortality, increased LOS, and cost.

Costs of hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) and its control

For most countries badly affected by methicillin-resistant Staphylococcus aureus (MRSA) there have been many years of debate about its relative virulence compared with methicillin-susceptible S. aureus (MSSA) and whether it could be controlled. Now that it is endemic in the majority of hospitals around the world, it is clear that it is at least as virulent as MSSA and is an additional burden of healthcare-acquired infection. There is increasing evidence that, despite this endemicity, control efforts can be successful, although they are often perceived as expensive. In reality, there is a large body of consistent evidence that control is highly cost effective, particularly in the context of the huge societal costs of MRSA and the future ever-greater threats that it poses.

Reference group choice and antibiotic resistance outcomes

Two types of cohort studies examining patients infected with methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) were contrasted, using different reference groups. Cases were compared to uninfected patients and patients infected with the corresponding, susceptible organism. VRE and MRSA were associated with adverse outcomes. The effect was greater when uninfected control patients were used.

Costs associated with a strict policy to eradicate methicillin-resistant Staphylococcus aureus in a Dutch University Medical Center: a 10-year survey

Although the Dutch policy to eradicate methicillin-resistant Staphylococcus aureus (MRSA) is very strict compared to policies employed in other countries, it has proven to be successful epidemiologically (incidence of MRSA in the Netherlands, <0.5%). The present study was performed to investigate both the financial and the logistical consequences of this strict, so-called "search and destroy" policy in the Netherlands. The data were based on a 10-year survey (1991-2000) of screening, surveillance, and outbreaks at the University Medical Center Utrecht. The consequences of the policy were determined by a panel comprising physicians from the Department of Surgery, the Department of Medical Microbiology, Subdivision Hospital Hygiene and Infection Prevention, the Department of Pharmacy, and Household Services. The costs associated with the policy were also calculated, including those for additional (disposable) material, cultures, specific medication, decontamination, and closing of the wards. Over the course of the 10 years, implementation of the MRSA policy resulted in more than 2,265 lost hospitalization days. In addition, the wards had to be closed 48 times, 29 healthcare workers had to temporarily discontinue working, and 78,000 additional cultures had to be performed. The total cost reached 6 million Dutch guilders (euro 2,800,000). The financial and logistical consequences were then compared to those in a hypothetical situation without the "search and destroy" policy. In such a situation, the hospital would be faced with an increased incidence of MRSA, vancomycin intermediate-susceptible Staphylococcus aureus, and vancomycin-resistant enterococci. The costs associated with the use of alternative antibiotics, required in a scenario of high endemic-level MRSA, would be at least twice as high as the costs expended in the actual situation, thus demonstrating that a strict MRSA policy is financially worthwhile.

Staphylococcus aureus bacteremia in patients with prosthetic devices: costs and outcomes

PURPOSE

Although Staphylococcus aureus is a leading cause of nosocomial infection, little is known about the impact of S. aureus bacteremia on patients with prosthetic devices. This investigation sought to define the clinical outcome, health care resource use, and infection-associated costs of S. aureus bacteremia in patients with prostheses.

SUBJECTS AND METHODS

All hospitalized patients with a prosthetic device and S. aureus bacteremia during the 96-month study period were identified prospectively. Clinical data were collected at the time of hospitalization. Data regarding infection-related resource utilization and infection-related costs within 12 weeks of the initial bacteremia were also recorded.

RESULTS

298 patients with > or =1 prosthesis and S. aureus bacteremia were identified (cardiovascular device--122 patients, orthopedic device--73 patients, long-term catheter--71 patients, and other devices-32 patients). Overall, 58% of patients underwent surgery as a consequence of the infection. Infection-related complications occurred in 41% and the overall 12-week mortality was 27%. The mean infection-related cost was 67439 dollars for patients with hospital-acquired S. aureus bacteremia and 37868 dollars for community-acquired S. aureus bacteremia (cost difference 29571 dollars; 95% confidence interval, 14370 dollars-49826 dollars). Rates of device infection, complications, 12-week mortality, and mean cost varied by prosthesis type.

CONCLUSION

S. aureus bacteremia in patients with prosthetic devices is associated with frequent complications, substantial cost, and significant health care resource utilization.

Cost analysis of a hospital-wide selective screening programme for methicillin-resistant Staphylococcus aureus (MRSA) carriers in the context of diagnosis related groups (DRG) payment

The costs of a hospital-wide selective screening programme were analysed for a period of 19 months. During this time, 539 inpatients were screened, of whom 111 were MRSA-positive. Based on microbiological costs (staff and materials) and the costs of preventive contact isolation for 2 days until microbiological results were available (including material costs for medical consumable goods and the costs of additional nursing time), a total of 26,241.51 Euro was spent for the 539 patients screened. Based on cost units, the costs were 39.96 Euro for a patient found to be MRSA-negative and 82.33 Euro for a patient found to be MRSA-positive. Under the prospective diagnosis related groups (DRG) payment system in Germany, the costs of a prolonged hospital stay resulting from a hospital-acquired MRSA infection (HA-MRSA-I) are not reimbursed adequately by revenues, with a calculated average cost-revenue loss/patient with HA-MRSA-I of 5705.75 Euro. The screening programme was able to prevent 48% of predicted HA-MRSA-Is (35.2 patients with infection), thereby saving a predicted 200,782.73 Euro. After subtracting the screening costs, there was a net saving of 110,236.56 Euro annually. A sensitivity analysis of the break-even points for different screening frequencies and different MRSA incidence rates indicated that the screening programme became cost-effective at a low MRSA incidence rate, meaning that it can be recommended for most hospitals with an MRSA problem.