title: Performance of a clinical decision support system and of clinical pharmacists in preventing drug-drug interactions on a geriatric ward.
abstract: BACKGROUND
  Drug-drug interactions (DDIs) can lead to adverse drug events and compromise patient safety. Two common approaches to reduce these interactions in hospital practice are the use of clinical decision support systems and interventions by clinical pharmacists.
  
  
  OBJECTIVE
  To compare the performance of both approaches with the main objective of learning from one approach to improve the other.
  
  
  METHODS
  Acute geriatric ward in a university hospital.
  
  
  METHODS
  Prospective single-centre, cohort study of patients admitted to the geriatric ward. An independent pharmacist compared the clinical decision support alerts with the DDIs identified by clinical pharmacists and evaluated their interventions. Contextual factors used by the clinical pharmacists for evaluation of the clinical relevance were analysed. Adverse drug events related to DDIs were investigated and the causality was evaluated by a clinical pharmacologist based on validated criteria.
  
  
  METHODS
  Number of alerts, interventions and the acceptance rates.
  
  
  RESULTS
  Fifty patients followed by the clinical pharmacists, were included. The clinical pharmacists identified 240 DDIs (median of 3.5 per patient) and advised a therapy change for 16 of which 13 (81.2 %) were accepted and three (18.8 %) were not. The decision support system generated only six alerts of which none were accepted by the physicians. Thirty-seven adverse drug events were identified for 29 patients that could be related to 55 DDIs. For two interactions the causality was evaluated as certain, for 31 as likely, for ten as possible and for 12 as unlikely. Mainly intermediate level interactions were related to adverse drug events. Contextual factors taken into account by the clinical pharmacists for evaluation of the interactions were blood pressure, international normalised ratio, heart rate, potassium level and glycemia. Additionally, the clinical pharmacists looked at individual administration intervals and drug sequence to determine the clinical relevance of the interactions.
  
  
  CONCLUSIONS
  Clinical pharmacists performed better than the decision support system mainly because the system screened only for high level DDIs and because of the low specificity of the alerts. This specificity can be increased by including contextual factors into the logic and by defining appropriate screening intervals that take into account the sequence in which the drugs are given.
authors.affiliation: Faculty of Medicine and Pharmacy, Research Group Clinical Pharmacology and Clinical Pharmacy (KFAR), Vrije Universiteit Brussel, 1090, Brussels, Belgium, Pieter.Cornu@vub.ac.be.
authors.forename: Pieter
authors.initials: P
authors.lastname: Cornu
authors.forename: Stephane
authors.initials: S
authors.lastname: Steurbaut
authors.forename: Sabina
authors.initials: S
authors.lastname: Soštarić
authors.forename: Aleš
authors.initials: A
authors.lastname: Mrhar
authors.forename: Alain G
authors.initials: AG
authors.lastname: Dupont
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003133:Commission on Professional and Hospital Activities; D020000:Decision Support Systems, Clinical / Q000706:statistics & numerical data*; D004347:Drug Interactions; D005260:Female; D005853:Geriatrics / Q000706:statistics & numerical data; D005919:Glomerular Filtration Rate; D006785:Hospitals, University / Q000706:statistics & numerical data; D006801:Humans; D007902:Length of Stay; D008297:Male; D010595:Pharmacists / Q000706:statistics & numerical data*; D010607:Pharmacy Service, Hospital / Q000706:statistics & numerical data*; D011446:Prospective Studies