Factors Associated with Antimicrobial Use in Nursing Homes: A Multilevel Model

OBJECTIVES: To describe antimicrobial prescribing patterns in nursing homes. DESIGN: Retrospective, observational study. SETTING: Total of 73 nursing homes in four U.S. states; study period was from September 1, 2001, through February 28, 2002. PARTICIPANTS: Four thousand seven hundred eighty nursing home residents. MEASUREMENTS: Number and type of antimicrobials, indication for their use, and resident and facility factors associated with antimicrobial use in nursing homes. RESULTS: Of 4,780 residents, 2,017 (42%) received one or more antibiotic courses. Overall, residents received a mean of 4.8 courses/1,000 resident‐days (mean facility range 0.4–23.5). In multivariable analysis, higher probability of nursing home discharge and of being categorized in the rehabilitation, extensive services, special care, or clinically complex Resource Utilization Groups were associated with higher rates of antimicrobial usage. Three drug classes accounted for nearly 60% of antimicrobial courses—fluoroquinolones (38%), first‐generation cephalosporins (11%), and macrolides (10%). The most common conditions for which antimicrobials were prescribed were respiratory tract (33%) and urinary tract (32%) infections. CONCLUSION: Antibiotic use is variable in nursing homes. Targeting educational and other antimicrobial use interventions to the treatment of certain clinical diagnoses and conditions may be an appropriate strategy for optimizing antimicrobial use in this setting.