Background: The benefits on clinical practice of a clinical decision support system (CDSS) are predominantly determined by the quality of the clinical rules used in this system. Therefore, it is essential to investigate the performance and potential benefits on quality of care of these rules.
Methods: A clinical rule assisting physicians in selecting the appropriate dosage according to renal function of frequently prescribed antimicrobials was developed. In 2004, 1788 patients admitted to the intensive care unit (ICU) for more than 12 h were included in this retrospective study. The actual number of dosage adjustments without the support of the CDSS was compared with the theoretical number of dosage adjustments determined by the clinical rule in patients with moderate (creatinine clearance (Cl(creat)) 10-50 ml/min) and severe (Cl(creat) <10 ml/min) renal dysfunction. If dosage adjustment was omitted, the duration of excessive anti-infective dosing and extra drug costs involved was determined.
Results: Dosage adjustment of antimicrobials was omitted in 163 patients (86%) with moderate renal failure and 13 patients (54%) with severe renal failure. Excessive exposure was most frequently detected in patients receiving fluconazole and ciprofloxacin (median duration of 6 days). In our ICU alone, more than 16,000 euro ($19 000) can be saved annually by adjusting the dosage according to renal function of frequently prescribed antimicrobials.
Conclusions: Despite intensive monitoring of patients in the ICU, dosage adjustment of antimicrobials is often omitted. Implementing this clinical rule has the potential to contribute to a significant improvement in medication safety and is expected to generate substantial savings.