Antimicrobial prescribing in long-term care facilities: Prospective evaluation of potential antimicrobial use and cost indicators

Background: Few studies exist regarding methods of monitoring antimicrobial prescribing in the long-term care setting. Methods. Data were collected monthly in 4 long-term care facilities (LTCFs) for 20 to 26 months. The data included incidence (No. of antimicrobial cou rses started per 1000 resident care days) of antimicrobial use, antimicrobi al utilization ratio (ratio of the number of antimicrobial-days to the numb er of resident care days), cost of antimicrobial-day, and cost of therapy p er resident care day. In one facility, physician-specific data were also co llected. Results: Seasonal variation in the incidence of antimicrobial use was ident ified, with the highest rates occurring in the winter months. Significant d ifferences in the mean incidence of antimicrobial use, mean antimicrobial u tilization ratio, mean cost per antimicrobial-day, and mean cost per reside nt care day were identified among the 4 LTCFs during the study period A sig nificant correlation existed between incidence of antimicrobial use or anti microbial utilization ratio and the overall infection rate or site-specific rates when the data from all 4 LTCFs were aggregated for analysis. Monthly variation in cast per antimicrobial-day was best explained by the monthly variation in prescribing of high-cost (>$15 per day) agents. With these sam e parameters for use and cost, considerable variation in prescribing and co st of therapy was noted among 7 physicians in the same facility. Conclusions: The parameters evaluated detected significant differences in p rescribing and cost of antimicrobials among 4 LTCFs. If these findings are verified in larger studies, these parameters may be useful for monitoring t rends in prescribing and for interfacility comparisons after adjustment for case-mix differences.