A Before-and-After Study of the Effectiveness of an Antimicrobial Stewardship Program in Critical Care

We evaluated the use of antimicrobials expressed as defined daily doses (DDDs) per 1,000 patient days and days of therapy (DOT) per 100 occupied bed-days in a intensive care unit (ICU) of a general hospital in Barcelona, Spain, before and after implementation of an antimicrobial stewardship (AMS) program (2007 to 2010 versus 2011 to 2015). The quarterly costs of antimicrobials used in the ICU and its weight in the overall hospital costs of antimicrobials were calculated. The effect of the applied AMS program on DDDs and DOT time series data was analyzed by means of intervention time series analysis. A total of 5,002 patients were included (1,971 for the first [before] period and 3,031 for the second [after] period). The percentage of patients treated with one or more antimicrobials decreased from 88.6 to 77.2% (P -0.001). DDDs decreased from 246.8 to 192.3 (mean difference, -54.5; P -0.001) and DOT from 66.7 to 54.6 (mean difference, -12.1; P -0.066). The mean cost per trimester decreased from (sic) 115,543 to (sic) 73,477 (mean difference, -42,065.4 euros; P<0.001), and the percentage of ICU antimicrobials cost with respect to the total cost of hospital antimicrobials decreased from 28.5 to 22.8% (mean difference, -5.59; P=0.023). Implementation of an AMS program in the ICU was associated with a marked reduction in the use of antimicrobials, with cost savings close to one million euros since its implementation. An AMS program can have a significant impact on optimizing antimicrobial use in critical care practice.