title: Examining variations in prescribing safety in UK general practice: cross sectional study using the Clinical Practice Research Datalink.
abstract: OBJECTIVE
  What is the prevalence of different types of potentially hazardous prescribing in general practice in the United Kingdom, and what is the variation between practices?
  
  
  METHODS
  A cross sectional study included all adult patients potentially at risk of a prescribing or monitoring error defined by a combination of diagnoses and prescriptions in 526 general practices contributing to the Clinical Practice Research Datalink (CPRD) up to 1 April 2013. Primary outcomes were the prevalence of potentially hazardous prescriptions of anticoagulants, anti-platelets, NSAIDs, β blockers, glitazones, metformin, digoxin, antipsychotics, combined hormonal contraceptives, and oestrogens and monitoring by blood test less frequently than recommended for patients with repeated prescriptions of angiotensin converting enzyme inhibitors and loop diuretics, amiodarone, methotrexate, lithium, or warfarin.
  
  
  CONCLUSIONS
  49 927 of 949 552 patients at risk triggered at least one prescribing indicator (5.26%, 95% confidence interval 5.21% to 5.30%) and 21 501 of 182 721 (11.8%, 11.6% to 11.9%) triggered at least one monitoring indicator. The prevalence of different types of potentially hazardous prescribing ranged from almost zero to 10.2%, and for inadequate monitoring ranged from 10.4% to 41.9%. Older patients and those prescribed multiple repeat medications had significantly higher risks of triggering a prescribing indicator whereas younger patients with fewer repeat prescriptions had significantly higher risk of triggering a monitoring indicator. There was high variation between practices for some indicators. Though prescribing safety indicators describe prescribing patterns that can increase the risk of harm to the patient and should generally be avoided, there will always be exceptions where the indicator is clinically justified. Furthermore there is the possibility that some information is not captured by CPRD for some practices-for example, INR results in patients receiving warfarin.
  
  
  CONCLUSIONS
  The high prevalence for certain indicators emphasises existing prescribing risks and the need for their appropriate consideration within primary care, particularly for older patients and those taking multiple medications. The high variation between practices indicates potential for improvement through targeted practice level intervention.
  
  
  BACKGROUND
  National Institute for Health Research through the Greater Manchester Primary Care Patient Safety Translational Research Centre (grant No GMPSTRC-2012-1). Data from CPRD cannot be shared because of licensing restrictions.
authors.affiliation: NIHR Greater Manchester Primary Care Patient Safety Translational Research Centre, Centre for Primary Care, Institute of Population Health, University of Manchester, Manchester M13 9PL, UK jill.stocks@manchester.ac.uk.
authors.forename: S Jill
authors.initials: SJ
authors.lastname: Stocks
authors.affiliation: NIHR School for Primary Care Research, Centre for Primary Care, Institute of Population Health, University of Manchester, Manchester, UK Centre for Health Informatics, Institute of Population Health, University of Manchester, Manchester, UK.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Kontopantelis
authors.affiliation: Centre for Health Informatics, Institute of Population Health, University of Manchester, Manchester, UK.
authors.forename: Artur
authors.initials: A
authors.lastname: Akbarov
authors.affiliation: Division of Primary Care, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Rodgers
authors.affiliation: Division of Primary Care, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, UK.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Avery
authors.affiliation: NIHR Greater Manchester Primary Care Patient Safety Translational Research Centre, Centre for Primary Care, Institute of Population Health, University of Manchester, Manchester M13 9PL, UK Centre for Pharmacoepidemiology and Drug Safety, Manchester Pharmacy School, University of Manchester, Manchester Academic Health Sciences Centre (MAHSC), Manchester, UK.
authors.forename: Darren M
authors.initials: DM
authors.lastname: Ashcroft
mesh_terms: D000328:Adult; D000368:Aged; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D005194:Family Practice / Q000592:standards* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D019300:Medical Errors / Q000706:statistics & numerical data*; D008875:Middle Aged; D061214:Patient Safety / Q000592:standards*; D010818:Practice Patterns, Physicians' / Q000592:standards* / Q000706:statistics & numerical data; D055553:Prescription Drugs / Q000627:therapeutic use*; D006113:United Kingdom
chemical_list: D055553:Prescription Drugs