An evaluation of the impact of antibiotic stewardship on reducing the use of high-risk antibiotics and its effect on the incidence of Clostridium difficile infection in hospital settings

A modified method for measuring antibiotic use in healthcare settings: implications for antibiotic stewardship and benchmarking

OBJECTIVES

To determine whether adjusting the denominator of the common hospital antibiotic use measurement unit (defined daily doses/100 bed-days) by including age-adjusted comorbidity score (100 bed-days/age-adjusted comorbidity score) would result in more accurate and meaningful assessment of hospital antibiotic use.

METHODS

The association between the monthly sum of age-adjusted comorbidity and monthly antibiotic use was measured using time-series analysis (January 2008 to June 2012). For the purposes of conducting internal benchmarking, two antibiotic usage datasets were constructed, i.e. 2004-07 (first study period) and 2008-11 (second study period). Monthly antibiotic use was normalized per 100 bed-days and per 100 bed-days/age-adjusted comorbidity score.

RESULTS

Results showed that antibiotic use had significant positive relationships with the sum of age-adjusted comorbidity score (P = 0.0004). The results also showed that there was a negative relationship between antibiotic use and (i) alcohol-based hand rub use (P = 0.0370) and (ii) clinical pharmacist activity (P = 0.0031). Normalizing antibiotic use per 100 bed-days contributed to a comparative usage rate of 1.31, i.e. the average antibiotic use during the second period was 31% higher than during the first period. However, normalizing antibiotic use per 100 bed-days per age-adjusted comorbidity score resulted in a comparative usage rate of 0.98, i.e. the average antibiotic use was 2% lower in the second study period. Importantly, the latter comparative usage rate is independent of differences in patient density and case mix characteristics between the two studied populations.

CONCLUSIONS

The proposed modified antibiotic measure provides an innovative approach to compare variations in antibiotic prescribing while taking account of patient case mix effects.

Antimicrobial stewardship program implementation in a medical intensive care unit at a tertiary care hospital in Saudi Arabia

BACKGROUND AND OBJECTIVES

Antimicrobial stewardship programs (ASPs) have shown to prevent the emergence of antimicrobial resistance associated with an inappropriate antimicrobial use. The primary objective of this study was to compare the prescribing appropriateness rate of the empirical antibiotic therapy before and after the ASP implementation in a tertiary care hospital. Secondary objectives include the rate of Clostridium difficile-associated diarrhea (CDAD), physicians' acceptance rate, patient's intensive care unit (ICU) course, total utilization using defined daily dose, and total direct cost of antibiotics.

DESIGN AND SETTINGS

This is a comparative, historically controlled study. Adult medical ICU patients were enrolled in a prospective fashion under the active ASP arm and compared with historical patients who were admitted to the same unit before the ASP implementation. This study was approved by the institutional review board, and the need for informed consent was waived because the interventions and recommendations were evidence based and considered the standard of care. The study was conducted at KFSHRC, Riyadh.

METHODS

Adult medical ICU patients were enrolled under the active ASP arm if they were on any of the 5 targeted antibiotics (piperacillin/tazobactam, imipenem/cilastatin, meropenem, vancomycin, tigecycline), and had no official infectious disease consultation. The interventions were conducted via prospective audit and feedback.

RESULTS

A total of 73 subjects were recruited, 49 in historical control and 24 in the active arm. The appropriateness of empirical antibiotics was improved from 30.6% (15/49) in the historical control arm to 100% (24/24) in the proactive ASP arm (P value < .05). For the ASP group, initially 79.1% (19/24) of the antibiotic uses were inappropriate and diminished by ASPs to 0% on the recommendations implementation. A total of 27 interventions were made with an acceptance rate of 96.3%. The rate of CDAD did not differ between the groups. A reduction in antibiotics utilization and direct cost were also noticed in the ASP arm.

CONCLUSION

A proactive ASP is a vital approach in optimizing the appropriate empirical antibiotics utilization in an ICU setting in tertiary care hospitals. This study highlights the importance of such a program and may serve as a foundation for further ASP initiatives particularly in our region.

The impact of cefepime as first line therapy for neutropenic fever on Clostridium difficile rates among hematology and oncology patients

After changing empiric treatment of febrile neutropenia from meropenem to cefepime, the effect on Clostridium difficile infection (CDI) was investigated. The change was assessed using an autoregressive model. A significant increase in CDI rates occurred following the introduction of cefepime. There may be an association between increased cefepime usage and CDI.

Clostridium difficile exposure as an insidious source of infection in healthcare settings: an epidemiological model

BACKGROUND

Clostridium difficile is the leading cause of infectious diarrhea in hospitalized patients. Its epidemiology has shifted in recent years from almost exclusively infecting elderly patients in whom the gut microbiota has been disturbed by antimicrobials, to now also infecting individuals of all age groups with no recent antimicrobial use.

METHODS

A stochastic mathematical model was constructed to simulate the modern epidemiology of C. difficile in a healthcare setting, and, to compare the efficacies of interventions.

RESULTS

Both the rate of colonization and the incidence of symptomatic disease in hospital inpatients were insensitive to antimicrobial stewardship and to the prescription of probiotics to expedite healthy gut microbiota recovery, suggesting these to be ineffective interventions to limit transmission. Comparatively, improving hygiene and sanitation and reducing average length of stay more effectively reduced infection rates. Although the majority of new colonization events are a result of within-hospital ward exposure, simulations demonstrate the importance of imported cases with new admissions.

CONCLUSIONS

By analyzing a wide range of screening sensitivities, we identify a previously ignored source of pathogen importation: although capturing all asymptomatic as well as symptomatic introductions, individuals who are exposed but not yet colonized will be missed by even a perfectly sensitive screen on admission. Empirical studies to measure the duration of this latent period of infection will be critical to assessing C. difficile control strategies. Moreover, identifying the extent to which the exposed category of individual contributes to pathogen importation should be explicitly considered for all infections relevant to healthcare settings.

Antimicrobial stewardship and Clostridium difficile-associated diarrhea

Antimicrobial stewardship programs are essential to health care institutions to promote the appropriate use of antibiotics not only to decrease antimicrobial resistance but to prevent the spread and infection of Clostridium difficile. Clostridium difficile-associated diarrhea is increasing rapidly in the United States and is now considered a major public health problem that poses an immediate threat to the health of patients prescribed antibiotics, more so than antimicrobial resistance. Clostridium difficile-associated disease is the result of collateral damage to the normal bacterial flora of the human body, which is an inevitable consequence of any antibiotic use. Antimicrobial stewardship programs such as audit with feedback and antibiotic restriction are designed to help limit Clostridium difficile infections and other hospital-associated organisms by optimizing antimicrobial selection, dosing, de-escalation, and duration of therapy. These programs also incorporate implementation of hospital-wide guidelines, staff education, enforcement of infection-control policies, and the use of electronic medical records when possible to help control antibiotic use. This article reviews the literature on how antimicrobial stewardship programs impact Clostridium difficile rates and discusses experiences in designing, implementing, monitoring, and follow-through of such programs.

Excess risk of Clostridium difficile infection in ovarian cancer is related to exposure to broad-spectrum antibiotics

PURPOSE

The purpose of the study was to determine if a diagnosis of ovarian cancer is independently associated with an increased risk of Clostridium difficile infection (CDI).

METHODS

The University HealthSystem Consortium database was queried to perform a retrospective cohort study of women with and without ovarian cancer who were diagnosed with CDI. Inpatients undergoing total hysterectomy from 2008 to 2012 were studied. Ovarian cancer patients were compared to non-ovarian cancer patients to evaluate relative risk (RR) of CDI. Adjustment was made for known or suspected CDI risk factors to determine RR of CDI independent of these variables.

RESULTS

In this study, 115,203 patients were included. CDI was reported in 0.80 % of ovarian cancer patients and in 0.31 % of non-ovarian cancer patients (RR = 2.50; 95 % confidence interval (CI) = 2.02 to 3.35). Stratification by age, presence of other comorbidities, or administration of antineoplastic drugs did not significantly modify the elevated risk associated with ovarian cancer. Significantly increased risk in ovarian cancer patients was no longer observed after controlling for broad-spectrum antibiotic administration (RR = 1.28, 95 % CI = 0.39 to 4.13). Compared to non-ovarian cancer patients, ovarian cancer patients were more frequently treated with broad-spectrum antibiotics, had a 39 % longer mean duration of therapy, and had 2.5-fold greater mean total exposure to broad-spectrum antibiotics.

CONCLUSIONS

After adjustment for antibiotic use, ovarian cancer patients are not at excess risk of CDI. Additional studies are needed to understand the patterns of broad-spectrum antibiotic prescription for ovarian cancer patients leading to increased exposure. If feasible, reduction of this exposure may decrease morbidity in this population.

Impact of an enhanced antibiotic stewardship on reducing methicillin-resistant Staphylococcus aureus in primary and secondary healthcare settings

The objective of this study was to evaluate the impact of restricting high-risk antibiotics on methicillin-resistant Staphylococcus aureus (MRSA) incidence rates in a hospital setting. A secondary objective was to assess the impact of reducing fluoroquinolone use in the primary-care setting on MRSA incidence in the community. This was an interventional, retrospective, ecological investigation in both hospital and community (January 2006 to June 2010). Segmented regression analysis of interrupted time-series was employed to evaluate the intervention. The restriction of high-risk antibiotics was associated with a significant change in hospital MRSA incidence trend (coefficient=-0·00561, P=0·0057). Analysis showed that the intervention relating to reducing fluoroquinolone use in the community was associated with a significant trend change in MRSA incidence in community (coefficient=-0·00004, P=0·0299). The reduction in high-risk antibiotic use and fluoroquinolone use contributed to both a reduction in incidence rates of MRSA in hospital and community (primary-care) settings.

Interventions to improve antibiotic prescribing practices for hospital inpatients

BACKGROUND

The first publication of this review in Issue 3, 2005 included studies up to November 2003. This update adds studies to December 2006 and focuses on application of a new method for meta-analysis of interrupted time series studies and application of new Cochrane Effective Practice and Organisation of Care (EPOC) Risk of Bias criteria to all studies in the review, including those studies in the previously published version. The aim of the review is to evaluate the impact of interventions from the perspective of antibiotic stewardship. The two objectives of antibiotic stewardship are first to ensure effective treatment for patients with bacterial infection and second support professionals and patients to reduce unnecessary use and minimize collateral damage.

OBJECTIVES

To estimate the effectiveness of professional interventions that, alone or in combination, are effective in antibiotic stewardship for hospital inpatients, to evaluate the impact of these interventions on reducing the incidence of antimicrobial-resistant pathogens or Clostridium difficile infection and their impact on clinical outcome.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE from 1980 to December 2006 and the EPOC specialized register in July 2007 and February 2009 and bibliographies of retrieved articles. The main comparison is between interventions that had a restrictive element and those that were purely persuasive. Restrictive interventions were implemented through restriction of the freedom of prescribers to select some antibiotics. Persuasive interventions used one or more of the following methods for changing professional behaviour: dissemination of educational resources, reminders, audit and feedback, or educational outreach. Restrictive interventions could contain persuasive elements.

SELECTION CRITERIA

We included randomized clinical trials (RCTs), controlled clinical trials (CCT), controlled before-after (CBA) and interrupted time series studies (ITS). Interventions included any professional or structural interventions as defined by EPOC. The intervention had to include a component that aimed to improve antibiotic prescribing to hospital inpatients, either by increasing effective treatment or by reducing unnecessary treatment. The results had to include interpretable data about the effect of the intervention on antibiotic prescribing or microbial outcomes or relevant clinical outcomes.

DATA COLLECTION AND ANALYSIS

Two authors extracted data and assessed quality. We performed meta-regression of ITS studies to compare the results of persuasive and restrictive interventions. Persuasive interventions advised physicians about how to prescribe or gave them feedback about how they prescribed. Restrictive interventions put a limit on how they prescribed; for example, physicians had to have approval from an infection specialist in order to prescribe an antibiotic. We standardized the results of some ITS studies so that they are on the same scale (percent change in outcome), thereby facilitating comparisons of different interventions. To do this, we used the change in level and change in slope to estimate the effect size with increasing time after the intervention (one month, six months, one year, etc) as the percent change in level at each time point. We did not extrapolate beyond the end of data collection after the intervention. The meta-regression was performed using standard weighted linear regression with the standard errors of the coefficients adjusted where necessary.

MAIN RESULTS

For this update we included 89 studies that reported 95 interventions. Of the 89 studies, 56 were ITSs (of which 4 were controlled ITSs), 25 were RCT (of which 5 were cluster-RCTs), 5 were CBAs and 3 were CCTs (of which 1 was a cluster-CCT).Most (80/95, 84%) of the interventions targeted the antibiotic prescribed (choice of antibiotic, timing of first dose and route of administration). The remaining 15 interventions aimed to change exposure of patients to antibiotics by targeting the decision to treat or the duration of treatment. Reliable data about impact on antibiotic prescribing data were available for 76 interventions (44 persuasive, 24 restrictive and 8 structural). For the persuasive interventions, the median change in antibiotic prescribing was 42.3% for the ITSs, 31.6% for the controlled ITSs, 17.7% for the CBAs, 3.5% for the cluster-RCTs and 24.7% for the RCTs. The restrictive interventions had a median effect size of 34.7% for the ITSs, 17.1% for the CBAs and 40.5% for the RCTs. The structural interventions had a median effect of 13.3% for the RCTs and 23.6% for the cluster-RCTs. Data about impact on microbial outcomes were available for 21 interventions but only 6 of these also had reliable data about impact on antibiotic prescribing.Meta-analysis of 52 ITS studies was used to compare restrictive versus purely persuasive interventions. Restrictive interventions had significantly greater impact on prescribing outcomes at one month (32%, 95% confidence interval (CI) 2% to 61%, P = 0.03) and on microbial outcomes at 6 months (53%, 95% CI 31% to 75%, P = 0.001) but there were no significant differences at 12 or 24 months. Interventions intended to decrease excessive prescribing were associated with reduction in Clostridium difficile infections and colonization or infection with aminoglycoside- or cephalosporin-resistant gram-negative bacteria, methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis. Meta-analysis of clinical outcomes showed that four interventions intended to increase effective prescribing for pneumonia were associated with significant reduction in mortality (risk ratio 0.89, 95% CI 0.82 to 0.97), whereas nine interventions intended to decrease excessive prescribing were not associated with significant increase in mortality (risk ratio 0.92, 95% CI 0.81 to 1.06).

AUTHORS' CONCLUSIONS

The results show that interventions to reduce excessive antibiotic prescribing to hospital inpatients can reduce antimicrobial resistance or hospital-acquired infections, and interventions to increase effective prescribing can improve clinical outcome. This update provides more evidence about unintended clinical consequences of interventions and about the effect of interventions to reduce exposure of patients to antibiotics. The meta-analysis supports the use of restrictive interventions when the need is urgent, but suggests that persuasive and restrictive interventions are equally effective after six months.