By Timothy C. Jenkins, MD

Assistant Professor of Medicine, Denver Health and University of Colorado School of Medicine

Dr. Jenkins reports no financial relationships in this field of study.

SYNOPSIS: In a single academic medical center, changing from a strategy of prior authorization to prospective audit with feedback led to significantly increased total antibiotic use and use of agents with a broad spectrum of gram-negative activity.

SOURCE: Mehta JM, et al. Comparison of prior authorization and prospective audit with feedback for antimicrobial stewardship. Infect Control Hosp Epidemiol 2014;35(9):1092-1099.

Infectious Diseases Society of America (IDSA) guidelines for developing antimicrobial stewardship programs refer to two core antimicrobial stewardship strategies: prior authorization and prospective audit with provider feedback.1 With prior authorization, use of selected antibiotics requires approval from a stewardship team member; whereas prospective audit with feedback involves post-prescription review of antibiotic regimens by a stewardship team member with real-time recommendations to providers regarding antibiotic choice, dose, and duration of therapy. Both strategies have been shown to reduce antibiotic use in hospitals; however, the most effective approach has not been established.

In this study by Mehta and colleagues at the Hospital of the University of Pennsylvania, these two stewardship strategies were compared using a pre-intervention post-intervention study design. During the pre-intervention period, prior authorization was required for commonly used broad-spectrum antibiotics including cefepime, piperacillin/tazobactam, vancomycin, and antifungals. In June 2009, the prior authorization requirement for cefepime, piperacillin/tazobactam, and vancomycin was removed. Instead, prospective audit with provider feedback for all patients receiving these three antibiotics was performed each weekday. Importantly, the prior authorization requirement for other broad-spectrum antibiotics and antifungals was continued during the post-intervention period; these agents thus served as control groups. The authors evaluated changes in the trends of total antibiotic use, use of agents with broad gram-negative activity, antifungals, and length of hospital stay during 24-month periods before and after the change in the stewardship strategy.

Over 55,000 inpatients received antimicrobial therapy over the entire study; severity of illness was similar in both time periods. Use of antibiotics with broad gram-negative activity declined at a rate of -4.00 days of therapy (DOT) per 1000 patient days (PD) per month during the pre-intervention period. During the post-intervention period, use of these agents increased by 0.80 DOT/1000PD per month, for a slope increase of 4.80 DOT/1000PD per month after the change in the stewardship strategy (p < .001). Specifically, use of cefepime and piperacillin/tazobactam was declining during the pre-intervention period but increased by 3.21 DOT/1000PD per month (p = .003) after the transition to prospective audit with feedback. For the other antibiotics with broad-spectrum gram-negative activity for which prior authorization was required in both time periods, there was no significant change between the periods.

Use of vancomycin declined during the pre-intervention period but significantly increased after the transition to prospective audit with feedback (0.89 DOT/1000PD per month, p = .005). Interestingly, use of antifungal agents (one of the control groups) declined during the pre-intervention period but also increased during the post-intervention period (2.42 DOT/1000PD per month, p = .001). Total length of hospital stay and length of stay after the first dose of antibiotics were declining during the pre-intervention period but increased significantly after the change in stewardship strategy.

COMMENTARY

Both prior authorization and prospective audit with feedback have been shown to be effective strategies to reduce unnecessary antibiotic use in hospitals.1 In this academic medical center, changing from prior authorization to prospective audit with provider feedback for cefepime, piperacillin-tazobactam, and vancomycin was associated with increased use of these agents as well as increased overall antimicrobial use.

This study is novel in that it is the first to directly compare these two core antimicrobial stewardship interventions. The conclusions that can be drawn are somewhat limited given the single-center, pre-intervention/post-intervention study design. In addition, use of antifungals (a control group in which prior authorization was required in both periods) increased during the post-intervention period, raising the possibility that factors other than the change in the stewardship strategy may have impacted prescribing patterns. Nevertheless, the findings are intriguing and suggest that there could be important differences in the effectiveness of the two core stewardship strategies currently recommended by the IDSA.

It seems intuitive that an optimal stewardship approach might be to combine prior authorization and prospective audit with feedback, given their complementary nature. Initial prior authorization helps to ensure an appropriate indication exists for broad-spectrum, toxic, or expensive antibiotics and that these agents are optimally dosed, while prospective audit with feedback 48 to 72 hours later and beyond promotes de-escalation of therapy and shorter treatment courses. However, since not all stewardship programs may have the capacity to perform both interventions, the question of whether prior authorization or prospective audit with feedback is more effective remains relevant. Although the answer to this question may depend on a number of factors specific to the individual institution or stewardship program, the present study demonstrates that multicenter studies comparing these two strategies are warranted.

Reference

  1. Dellit TH, Owens RC, McGowan JE, Jr., et al. Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America guidelines for developing an institutional program to enhance antimicrobial stewardship. Clin Infect Dis 2007;44(2):159-177.