Antibiotic stewardship: Why we must, how we can

GOAL: BETTER CARE (NOT CHEAPER CARE OR LESS ANTIBIOTIC USE)

The primary goal of antibiotic stewardship is better patient care. The goal is not reduced antibiotic use or cost savings, although these could be viewed as favorable side effects. Sometimes, better patient care involves using more antibiotics: eg, a patient with presumed sepsis should be started quickly on broad-spectrum antibiotics, an action that also falls under antibiotic stewardship. The focus for stewardship efforts should be on optimizing appropriate use, ie, promoting the use of the right agent at the correct dosage and for the proper duration.

Stewardship improves clinical outcomes

Antibiotic stewardship is important not only to society but to individual patients.

Singh et al¹⁵ randomized patients suspected of having ventilator-associated pneumonia (but with a low likelihood of pneumonia) to either a 3-day course of ciprofloxacin or standard care (antibiotics for 10 to 21 days, with the drug and duration chosen by the treating physician). After 3 days, the patients in the experimental group were reevaluated, and antibiotics were stopped if the likelihood of pneumonia was still deemed low. In patients who received only the short course of antibiotics, mean length of stay in the intensive care unit was 9 days and the risk of acquiring an antibiotic-resistant superinfection during hospitalization was 14%, compared with a 15-day length of stay and 38% risk of antibiotic-resistant superinfection in patients in the standard treatment group.

Fishman¹⁶ reported a study at a single hospital that randomized patients to either receive standard care according to physician choice or be treated according to an antibiotic stewardship program. Patients in the antibiotic stewardship group were almost 3 times more likely than controls to receive appropriate therapy according to guidelines. More important, the antibiotic stewardship patients were almost twice as likely to be cured of their infection and were more than 80% less likely to have treatment failure.

DEVELOPING EFFECTIVE ANTIBIOTIC STEWARDSHIP PROGRAMS

A good model for improving antibiotic use is a recent nationwide program designed to reduce central line-associated bloodstream infections.¹⁷ Rates of these infections have dropped by about 50% over the past 5 years. The program included:

• Research to better understand the problem and how to fight it
• Well-defined programs and interventions
• Education to implement interventions, eg, deploying teams to teach better techniques of inserting and maintaining central lines
• A strong national measurement system (the CDC’s National Healthcare Safety Network) to track infections.

What constitutes an antibiotic stewardship program?

The CDC examined successful stewardship programs in a variety of hospital types, including large academic hospitals and smaller hospitals, and identified 7 common core elements that could serve as general principles that were common to successful antibiotic stewardship programs¹⁸:

• Leadership commitment from administration
• A single leader responsible for outcomes
• A single pharmacy leader
• Tracking of antibiotic use
• Regular reporting of antibiotic use and resistance
• Educating providers on use and resistance
• Specific improvement interventions.

Stewardship is harder in some settings

In reply to a CDC survey in 2014, 41% of more than 4,000 hospitals reported that they had antibiotic stewardship programs with all 7 core elements. The single element that predicted whether a complete program was in place was leadership support.¹⁹ The following year, 48% of respondents reported that they had a complete program in place. Percentages varied among states, with highs in Utah (77%) and California (70%) and lows in North Dakota (12%) and Vermont (7%). Large hospitals and major teaching hospitals were more likely to have a program with all 7 elements: 31% of hospitals with 50 or fewer beds had a complete program vs 66% of hospitals with at least 200 beds.²⁰

Short-stay, critical-access hospitals pose a special challenge, as only 26% reported having all core elements.^19,20 These facilities have fewer than 25 beds, and many patient stays are less than 3 days. Some do not employ full-time pharmacists or full-time clinicians. The CDC is collaborating with the American Hospital Association and the Pew Charitable Trusts to focus efforts on helping these hospitals, which requires a more flexible approach. About 100 critical-access hospitals nationwide have reported implementing all of the core elements and can serve as models for the others.

MEASURING IMPROVEMENT

The CDC has adopted a 3-pronged approach to measuring improvements in hospital antibiotic use:

• Estimate national aggregate antibiotic use described above
• Acquire information on antibiotic use at facility, practice, and provider levels
• Assess appropriate antibiotic use.

In hospitals, the CDC has concentrated on facility-level measurement. Hospitals need a system to track their own use and compare it with that of similar facilities. The CDC’s monitoring program, the Antibiotic Use Option of the National Healthcare Safety Network, captures electronic data on antibiotic use in a facility, enabling monitoring of use in each unit. Data can also be aggregated at regional, state, and national levels. This information can be used to develop benchmarks for antibiotic use, so that similar hospitals can be compared.

What is the ‘right’ amount of antibiotic use? Enter SAAR

Creating benchmarks for antibiotic use poses a number of challenges compared with most other areas in healthcare. Most public health measures are binary—eg, people either get an infection, a vaccination, or a smoking cessation intervention or not—and the direction of progress is clear. Antibiotics are different: not everybody needs them, but some people do. Usage should be reduced, but by exactly how much is unclear and varies between hospitals. In addition, being an outlier does not necessarily indicate a problem: a hospital unit for organ transplants will have high rates of antibiotic use, which is likely appropriate.

The CDC has taken initial steps to develop a risk-adjusted benchmark measure for hospital antibiotic use, the Standardized Antimicrobial Administration Ratio (SAAR). It compares a hospital’s observed antibiotic use with a calculation of predicted use based on its facility characteristics. Although still at an early stage, SAAR has been released and has been endorsed by the National Quality Forum. About 200 hospitals are submitting data to the CDC and collaborating with the CDC to evaluate the SAAR’s utility in driving improved antibiotic use.

Problems in measuring appropriate use

Measuring appropriate antibiotic use is easier in the outpatient setting, where detailed data have been collected for many years.

Fleming-Dutra et al²¹ compared medications prescribed during outpatient visits and the diagnoses coded for the visits. They found that about 13% of all outpatient visits resulted in an antibiotic prescription, 30% of which had no listed diagnosis that would justify an antibiotic (eg, viral upper respiratory infection). This kind of information provides a target for stewardship programs.

It is more difficult to conduct such a study in a hospital setting. Simply comparing discharge diagnoses to antibiotics prescribed is not useful: often antibiotics are started presumptively on admission for a patient with signs and symptoms of an infection, then stopped if the diagnosis does not warrant antibiotics, which is a reasonable strategy.

Also, many times, a patient with asymptomatic bacteriuria, which does not warrant antibiotics, is misdiagnosed as having a urinary tract infection, which does. So simply looking at the discharge code may not reveal whether therapy was appropriate.

Some studies have provided useful information. Fridkin et al²² studied 36 hospitals for the use of vancomycin, which is an especially good candidate drug for study because guidelines exist for appropriate use. Data were collected only from patients given vancomycin for more than 3 days, which should have eliminated empiric use of the drug and included only pathogen-driven therapy. Cases where therapy was for skin and soft-tissue infections were excluded because cultures are not usually obtained for these cases. Of patients given vancomycin, 9% had no diagnostic culture obtained at antibiotic initiation, 22% had diagnostic culture but results showed no gram-positive bacterial growth, and 5% had culture results revealing only oxacillin-susceptible Staphylococcus aureus. In 36% of cases, opportunities existed for improved prescribing.

Such data could be collected from the electronic medical record, and the CDC is focusing efforts in this direction.