Results: During the paper-based prescribing period 592 patients were included, and during the CPOE/CDSS period 603. Total costs of the paper-based system and CPOE/CDSS amounted to D 12.37 and D 14.91 per patient/day respectively. The Incremental Cost-Effectiveness Ratio (ICER) for medication errors was 3.54 and for preventable adverse drug events 322.70, indi- cating the extra amount (D ) that has to be invested in order to prevent one medication error or one pADE.
Conclusions: CPOE with basic CDSS contributes to a decreased risk of preventable harm. Overall, the extra costs of CPOE/CDSS needed to prevent one ME or one pADE seem to be acceptable.