title: Methodological variations and their effects on reported medication administration error rates.
abstract: BACKGROUND
  Medication administration errors (MAEs) are a problem, yet methodological variation between studies presents a potential barrier to understanding how best to increase safety. Using the UK as a case-study, we systematically summarised methodological variations in MAE studies, and their effects on reported MAE rates.
  
  
  METHODS
  Nine healthcare databases were searched for quantitative observational MAE studies in UK hospitals. Methodological variations were analysed and meta-analysis of MAE rates performed using studies that used the same definitions. Odds ratios (OR) were calculated to compare MAE rates between intravenous (IV) and non-IV doses, and between paediatric and adult doses.
  
  
  RESULTS
  We identified 16 unique studies reporting three MAE definitions, 44 MAE subcategories and four different denominators. Overall adult MAE rates were 5.6% of a total of 21 533 non-IV opportunities for error (OE) (95% CI 4.6% to 6.7%) and 35% of a total of 154 IV OEs (95% CI 2% to 68%). MAEs were five times more likely in IV than non-IV doses (pooled OR 5.1; 95% CI 3.5 to 7.5). Including timing errors of ±30 min increased the MAE rate from 27% to 69% of 320 IV doses in one study. Five studies were unclear as to whether the denominator included dose omissions; omissions accounted for 0%-13% of IV doses and 1.8%-5.1% of non-IV doses.
  
  
  CONCLUSIONS
  Wide methodological variations exist even within one country, some with significant effects on reported MAE rates. We have made recommendations for future MAE studies; these may be applied both within and outside the UK.
authors: Centre for Medication Safety and Service Quality, Pharmacy Department, Imperial College Healthcare NHS Trust,Charing Cross Hospital, London W6 8RF, UK. monsey.mcleod@imperial.nhs.uk
authors: Monsey Chan
authors: MC
authors: McLeod
authors: Nick
authors: N
authors: Barber
authors: Bryony Dean
authors: BD
authors: Franklin
mesh_terms: D004334:Drug Administration Schedule; D006801:Humans; D008508:Medication Errors / Q000517:prevention & control* / Q000706:statistics & numerical data*; D008510:Medication Systems, Hospital / Q000592:standards*; D011785:Quality Assurance, Health Care; D012307:Risk Factors; D017751:Safety Management / Q000379:methods*; D006113:United Kingdom