Use of a computer decision support system and antimicrobial therapy appropriateness.

Objective:  To determine whether antimicrobial (AM) courses ordered with an antimicrobial computer decision support system (CDSS) were more likely to be appropriate than courses ordered without the CDSS.

Design:  Retrospective cohort study. Blinded expert reviewers judged whether AM courses were appropriate, considering drug selection, route, dose, and duration.

Setting:  A 279-bed university-affiliated Department of Veterans Affairs (VA) hospital.

Patients:  A 500-patient random sample of inpatients who received a therapeutic AM course between October 2007 and September 2008. Intervention. An optional CDSS, available at the point of order entry in the VA computerized patient record system.

Results: CDSS courses were significantly more likely to be appropriate (111/254, 44%) compared with non-CDSS courses (81/246, 33%, P = .013). Courses were more likely to be appropriate when the initial provider diagnosis of the condition being treated was correct (168/273, 62%) than when it was incorrect, uncertain, or a sign or symptom rather than a disease (24/227, 11%, P < .001. In multivariable analysis, CDSS-ordered courses were more likely to be appropriate than non-CDSS-ordered courses (odds ratio [OR], 1.83; 95% confidence interval [CI], 1.13-2.98). Courses were also more likely to be judged appropriate when the initial provider diagnosis of the condition being treated was correct than when it was incorrect, uncertain, or a sign or symptom rather than a disease (OR, 3.56; 95% CI, 1.4-9.0).

Conclusions:  Use of the CDSS was associated with more appropriate AM use. To achieve greater improvements, strategies are needed to improve provider diagnoses of syndromes that are infectious or possibly infectious.