Out of Sight-Out of Mind: Impact of Cascade Reporting on Antimicrobial Usage

There is a paucity of data evaluating the strategy of suppressing broader-spectrum antibiotic susceptibilities on utilization. Cascade reporting (CR) is a strategy of reporting antimicrobial susceptibility test results in which secondary (eg, broader-spectrum, costlier) agents may only be reported if an organism is resistant to primary agents within a particular drug class. Our objective was to evaluate the impact of ceftriaxone-based cascade reporting on utilization of cefepime and clinical outcomes in patients with ceftriaxone-susceptible Escherichia and Klebsiella clinical cultures.

We compared post-CR (July 2014-June 2015) with baseline (July 2013-June 2014), evaluating utilization of cefepime, cefazolin, ceftriaxone, ampicillin derivatives, fluoroquinolones, piperacillin/tazobactam, ertapenem, and meropenem; new Clostridium difficile infection; and length of stay (LOS) after the positive culture, 30-day readmission, and in-hospital all-cause mortality.

Mean days of therapy (DOT) among patients who received any antibiotic for cefepime decreased from 1.229 days during the baseline period to 0.813 days post-CR (adjusted relative risk, 0.668; P < .0001). Mean DOT of ceftriaxone increased from 0.864 days to 0.962 days, with an adjusted relative risk of 1.113 (P = .004). No significant differences were detected in other antibiotics including ertapenem and meropenem, demonstrating the direct association of the decrease in cefepime utilization with CR based on ceftriaxone susceptibility. Average LOS in the study population decreased from 14.139 days to 10.882 days from baseline to post-CR and was found to be statistically significant (P < .0001).

In conclusion, we demonstrated significant association of decreased cefepime utilization with the implementation of a CR based on ceftriaxone susceptibility. We demonstrated the safety of deescalation, with LOS being significantly lower during the post-CR period than in the baseline period, with no change in in-hospital mortality.