title: A retrospective study on the incidences of adverse drug events and analysis of the contributing trigger factors.
abstract: OBJECTIVE
  To retrospectively determine the extent and types of adverse drug events (ADEs) from the patient cases sheets and identify the contributing factors of medication errors. To assess causality and severity using the World Health Organization (WHO) probability scale and Hartwig's scale, respectively.
  
  
  METHODS
  Hundred patient case sheets were randomly selected, modified version of the Institute for Healthcare Improvement (IHI) Global Trigger Tool was utilized to identify the ADEs; causality and severity were calculated utilizing the WHO probability scale and Hartwig's severity assessment scale, respectively.
  
  
  RESULTS
  In total, 153 adverse events (AEs) were identified using the IHI Global Trigger Tool. Majority of the AEs are due to medication errors (46.41%) followed by 60 adverse drug reactions (ADRs), 15 therapeutic failure incidents, and 7 over-dose cases. Out of the 153 AEs, 60 are due to ADRs such as rashes, nausea, and vomiting. Therapeutic failure contributes 9.80% of the AEs, while overdose contributes to 4.58% of the total 153 AEs. Using the trigger tools, we were able to detect 45 positive triggers in 36 patient records. Among it, 19 AEs were identified in 15 patient records. The percentage of AE/100 patients is 17%. The average ADEs/1000 doses is 2.03% (calculated).
  
  
  CONCLUSIONS
  The IHI Global Trigger Tool is an effective method to aid provisionally-registered pharmacists to identify ADEs quicker.
authors.affiliation: Unit of Pharmacy Practice, Faculty of Pharmacy, AIMST University, Bedong 08100, Kedah, Malaysia.
authors.forename: Aaseer Thamby
authors.initials: AT
authors.lastname: Sam
authors.affiliation: Unit of Pharmacy Practice, Faculty of Pharmacy, AIMST University, Bedong 08100, Kedah, Malaysia.
authors.forename: Looi Li
authors.initials: LL
authors.lastname: Lian Jessica
authors.affiliation: Unit of Pharmacology, Faculty of Pharmacy, AIMST University, Bedong 08100, Kedah, Malaysia.
authors.forename: Subramani
authors.initials: S
authors.lastname: Parasuraman
keywords: Adverse drug events; Hartwig's severity assessment scale; Institute for Healthcare Improvement Global Trigger Tool; World Health Organization probability scale