Limited efficacy of a nonrestricted intervention on antimicrobial prescription of commonly used antibiotics in the hospital setting: results of a randomized controlled trial.

Most interventions aimed at diminishing the use of antimicrobials in hospitals have focussed on newly introduced antibiotics and very few have been randomly controlled. We evaluated the impact on antibiotic consumption of an intervention without restrictions in antibiotic use, focussed on commonly used antibiotics with a controlled randomized trial. All new prescriptions of levofloxacin, carbapenems, or vancomycin in hospitalized patients were randomized to an intervention or a control group. Intervention consisted of an antibiotic regimen counselling targeted to match local antibiotic guidelines, performed using only patients' charts. Clinical charts of patients assigned to the control group were reviewed daily by a pharmacist. The primary endpoint was a reduction in consumption of the targeted antibiotics. Two hundred seventy-eight prescriptions corresponding to 253 patients were included: 146 were assigned to the intervention and 132 to the control group. Total consumption of the targeted antibiotics (median [IQR]) was slightly lower in the intervention (8 [4-12] defined daily doses [DDDs] per patient) than in the control group (10 [6-16] DDDs per patient; p = 0.04). No differences in number of DDDs were observed when antibiotics of substitution were included (11.05 [6-18.2] vs 10 [6-16.5] in the intervention and control groups, respectively, p = 0.13). The total number of days on treatment with the targeted antibiotics was lower in the intervention (4 [3-7] days per patient) than in the control group (6 [4-10] days per patient; p = 0.002). Differences in number of days on treatment only reached statistical significance in the prescriptions of carbapenems. There were no differences between intervention and control groups in terms of number of deaths, hospital readmissions, length of hospital stay, or antibiotic costs. In this trial, an intervention without restrictions focussed on antimicrobial prescriptions of commonly used antibiotics in the hospital setting had a limited efficacy to reduce consumption and did not save costs. Future strategies to promote a more rational antimicrobial use should be evaluated with a randomized controlled design.