Background: We implemented a computerized decision support system (CDSS) integrated in the in-house computerized physician order entry (CPOE) system to assist physicians with antimicrobial prescribing decisions in the context of the multicenter cluster-randomized COMPASS trial (NCT03120975). Some physicians in the intervention wards complained about the perceived extra-time associated with the use of the CDSS compared with routine prescribing through CPOE. The aim of this study was to compare the time needed to prescribe antimicrobials with and without the CDSS.

Methods: Physicians with and without previous experience with the COMPASS CDSS working at our hospital in Geneva, Switzerland, were recruited to prescribe antimicrobials using clinical vignettes. Physicians without experience received a brief explanation of the CDSS. Each physician received 2 groups of 5-7 clinical vignettes randomly selected from a pool of 28. Each group of vignettes included prescriptions with different levels of complexity (empiric versus targeted or pre-defined treatment, dose adjustment for renal function, oral switch, treatments for which COMPASS does not provide recommendations or where a deviation was necessary). Prescriptions were completed using the standard CPOE (first set), then using COMPASS (second set). A print version of the local antimicrobial guidelines was available for consultation. Time to complete each prescription was recorded (including time needed to consult paper guidelines). The Mann-Whitney test was used for comparisons. Consultation of guidelines booklet and concordance with local guidelines were assessed.

Results: Twenty-five physicians were recruited. Thirteen (52%) had previously used COMPASS. Among them, 11 (85%) estimated the extra-time being above 1 min. We evaluated a total of 296 vignettes. Overall, the median time to complete a prescription was 55.5 s (IQR 38-86) using COMPASS and 50 s (IQR 31-88) using the standard CPOE (p = 0.24). Concordance of prescriptions with local guidelines was similar with the 2 systems (127/148, 85.8% for both), but consultation of paper guidelines was more frequent when prescribing without the CDSS (49.3% (73/148) vs 22.3% (33/148)).

Conclusions: The increased time required for prescribing using COMPASS is overestimated by end-users. Information collected in the study will be used to streamline the prescribing process via COMPASS and increase acceptance.