610Incidence of Potentially Inappropriate Dual Antimicrobial Therapy in U.S. hospitals

Background. Overutilization of antimicrobial therapy places patients at risk for harm and contributes to antimicrobial resistance and escalating healthcare costs. Focusing on dual or redundant antimicrobial therapy is one recommended strategy to reduce overutilization and its attendant effects on patient safety and hospital costs. Design. This cohort study explored the incidence and economic impact of potentially inappropriate dual antimicrobial therapy. Patients. We conducted a retrospective analysis of inpatient administrative data drawn from 505 non-federal U.S. hospitals. All hospitalized patients discharged between January 1, 2008 and December 31, 2011, were eligible for study inclusion. Methods. Potentially inappropriate dual antimicrobial therapy was identified from pharmacy records and was defined as patients receiving treatment with overlapping antibiotic spectra for two or more consecutive days. We searched for presence of ICD-9-CM codes for CDI andMRSAand conducted additional analyses to determinewhether patients receiving dual therapy also had a test (presence of CPT codes) for CDI and/or MRSA. Results. We found evidence of potentially inappropriate, dual antimicrobial coverage for 21 different antimicrobial combinations in 394 of the 505 (78%) hospitals, representing a total of 27,132 cases. Examination of the 21,169 cases of redundant intravenous metronidazole use showed that only 6 percent of the cases (n = 1,180) had a recorded ICD-9-CM diagnosis code indicating the presence of CDI. Of the 27,132 patients receiving any of the 21 dual therapy combinations, only 13,202 (48.7 percent) had evidence of tests for either CDI orMRSA.High frequency redundancies were observed in four anti-anaerobic regimens, that accounted for 21,169 (78%) of the cases. Of these, metronidazole and piperacillin-tazobactam accounted for 64% (n = 17,326) of all potentially redundant cases. Days of dual therapy totaled 126,648 representing greater than $12 million in potentially avoidable healthcare costs. Conclusion. Our study suggests that there may be pervasive use of potentially inappropriate dual antimicrobial therapy within U.S hospitals. Appropriate use of antimicrobials may reduce the risk of harm to patients and lower healthcare costs. Disclosures. All authors: No reported disclosures.