Poster Abstract Session: Antimicrobial Resistant Infections: Treatment
Saturday, October 29, 2016
Room: Poster Hall
The incidence of infections caused by gram-negative multidrug resistant organisms (MDROs) is increasing. As a result, older antimicrobial agents, such as colistin, are increasingly utilized. Currently there is no universally accepted dosing strategy for colistin and studies have shown that manufacturer dosing may be suboptimal. Therefore, we developed colistin dosing guidelines (CDG) based on retrospective analyses and population pharmacokinetic studies. These guidelines are more aggressive compared to the manufacturer’s recommendations and include a weight-based loading dose followed by maintenance dosing based on body surface area and creatinine clearance. The purpose of this study was to analyze the safety and efficacy of the CDG.
This is a retrospective pre- and post- interventional study following the implementation of the CDG. Adult patients with infections caused by MDROs requiring >72 hours of IV colistin administration were included. The pre-group included patients receiving colistin dosed per manufacturer’s guidelines from Jan 1 - Dec 31, 2013. The post-group included patients receiving colistin dosed via the CDG from Jan 1 - Dec 31, 2015. The primary outcome analyzed was in-hospital mortality. Secondary outcomes included clinical cure, and incidence of renal and neurotoxicity.
A total of 62 patients were included in the analysis: 24 in the pre-group and 38 in the post-group. Post-CDG implementation, in-hospital mortality was significantly higher (12.5% vs. 50%, P<0.01) and clinical cure was lower (79.1% vs. 39.5%, P<0.01). However, there were significantly more critically ill patients in the post-group (45.8% vs. 84.2%, P=0.02). Additionally, more patients in the CDG group experienced toxicities attributable to colistin (37.5% pre-group vs. 47.4% post-group).
There does not appear to be a clear clinical advantage to dosing colistin more aggressively than recommended in the package insert; however, severity of illness may have confounded this finding in our cohort. Implementation of the CDG may have resulted in increased incidence of renal and neurotoxicity.