title: Interpreting adverse drug reaction (ADR) reports as hospital patient safety incidents.
abstract: BACKGROUND
  Adverse drug reactions (ADRs) are a reporting category in the National Patient Safety Agency (NPSA) incident reporting system, though the Medicines and Healthcare Products Regulatory Agency (MHRA) pharmacovigilance system is the more established method for collecting ADR data.
  
  
  CONCLUSIONS
  The majority of ADRs were shown to be of moderate risk to the patient, though some have a severe or catastrophic impact. Classification and reporting of ADRs according to NPSA guidance is possible but offers limited additional value to efforts to improve patient safety over and above the Yellow Card Scheme.
  
  
  OBJECTIVE
  In the UK, the National Patient Safety Agency (NPSA) includes adverse drug reactions as a reporting category, while the MHRA Yellow Card Scheme also collects data regarding adverse drug reactions (ADRs). In this study, we aimed to assess ADRs using NPSA criteria and discuss the resulting implications.
  
  
  METHODS
  ADRs identified in a 6-month prospective study of 3695 inpatient episodes were assessed according to their impact on the patient and on the organization, using tools developed by the NPSA.
  
  
  RESULTS
  Seven hundred and thirty-three (100%) ADRs were assessed. In terms of impact on the patient, 537 (73.3%) were categorized as 'low' (minor treatment), 181 (24.7%) as 'moderate' (moderate increase in treatment, no permanent harm), 14 (1.91%) as 'severe' (permanent harm) and 1 (0.14%) was categorized as 'catastrophic' (direct cause of death). In terms of impact on the organization, none was categorized as 'no harm/no risk', 508 (69.3%) as 'insignificant', 188 (25.6%) as 'minor', 25 (3.4%) as 'moderate', 12 (1.6%) as 'major' and none was classed as 'catastrophic'. Less than 2% of ADRs would be eligible for detailed analysis according to the NPSA guidance. The ADRs that cause incidents of greater significance relate to bleeding, renal impairment and Clostridium difficile infection.
  
  
  CONCLUSIONS
  Classification of ADRs according to NPSA guidance offers limited additional value over and above that offered by the Yellow Card System. A consistent message needs to be sent to prospective reporters of ADRs; the availability of more than one system is likely to confuse reporters and does not aid patient safety.
authors.affiliation: The Royal Liverpool and Broadgreen University Hospitals Trust, Prescot Street, Liverpool L7 8XP, UK. edavies@liverpool.ac.uk
authors.forename: Emma C
authors.initials: EC
authors.lastname: Davies
authors.forename: Christopher F
authors.initials: CF
authors.lastname: Green
authors.forename: David R
authors.initials: DR
authors.lastname: Mottram
authors.forename: Munir
authors.initials: M
authors.lastname: Pirmohamed
mesh_terms: D016907:Adverse Drug Reaction Reporting Systems; D064420:Drug-Related Side Effects and Adverse Reactions / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007297:Inpatients; D017891:Pharmacoepidemiology; D011446:Prospective Studies