title: Provision of social norm feedback to high prescribers of antibiotics in general practice: a pragmatic national randomised controlled trial.
abstract: BACKGROUND
  Unnecessary antibiotic prescribing contributes to antimicrobial resistance. In this trial, we aimed to reduce unnecessary prescriptions of antibiotics by general practitioners (GPs) in England.
  
  
  METHODS
  In this randomised, 2 × 2 factorial trial, publicly available databases were used to identify GP practices whose prescribing rate for antibiotics was in the top 20% for their National Health Service (NHS) Local Area Team. Eligible practices were randomly assigned (1:1) into two groups by computer-generated allocation sequence, stratified by NHS Local Area Team. Participants, but not investigators, were blinded to group assignment. On Sept 29, 2014, every GP in the feedback intervention group was sent a letter from England's Chief Medical Officer and a leaflet on antibiotics for use with patients. The letter stated that the practice was prescribing antibiotics at a higher rate than 80% of practices in its NHS Local Area Team. GPs in the control group received no communication. The sample was re-randomised into two groups, and in December, 2014, GP practices were either sent patient-focused information that promoted reduced use of antibiotics or received no communication. The primary outcome measure was the rate of antibiotic items dispensed per 1000 weighted population, controlling for past prescribing. Analysis was by intention to treat. This trial is registered with the ISRCTN registry, number ISRCTN32349954, and has been completed.
  
  
  RESULTS
  Between Sept 8 and Sept 26, 2014, we recruited and assigned 1581 GP practices to feedback intervention (n=791) or control (n=790) groups. Letters were sent to 3227 GPs in the intervention group. Between October, 2014, and March, 2015, the rate of antibiotic items dispensed per 1000 population was 126.98 (95% CI 125.68-128.27) in the feedback intervention group and 131.25 (130.33-132.16) in the control group, a difference of 4.27 (3.3%; incidence rate ratio [IRR] 0.967 [95% CI 0.957-0.977]; p<0.0001), representing an estimated 73,406 fewer antibiotic items dispensed. In December, 2014, GP practices were re-assigned to patient-focused intervention (n=777) or control (n=804) groups. The patient-focused intervention did not significantly affect the primary outcome measure between December, 2014, and March, 2015 (antibiotic items dispensed per 1000 population: 135.00 [95% CI 133.77-136.22] in the patient-focused intervention group and 133.98 [133.06-134.90] in the control group; IRR for difference between groups 1.01, 95% CI 1.00-1.02; p=0.105).
  
  
  CONCLUSIONS
  Social norm feedback from a high-profile messenger can substantially reduce antibiotic prescribing at low cost and at national scale; this outcome makes it a worthwhile addition to antimicrobial stewardship programmes.
  
  
  BACKGROUND
  Public Health England.
authors.affiliation: Behavioural Insights Team, London, UK; Imperial College London, London, UK. Electronic address: michael.hallsworth@behaviouralinsights.co.uk.
authors.forename: Michael
authors.initials: M
authors.lastname: Hallsworth
authors.affiliation: Public Health England, London, UK.
authors.forename: Tim
authors.initials: T
authors.lastname: Chadborn
authors.affiliation: Public Health England, London, UK.
authors.forename: Anna
authors.initials: A
authors.lastname: Sallis
authors.affiliation: Behavioural Insights Team, London, UK; Harvard Kennedy School, Cambridge, MA, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Sanders
authors.affiliation: Department of Health, London, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Berry
authors.affiliation: Public Health England, London, UK.
authors.forename: Felix
authors.initials: F
authors.lastname: Greaves
authors.affiliation: Public Health England, London, UK.
authors.forename: Lara
authors.initials: L
authors.lastname: Clements
authors.affiliation: Department of Health, London, UK.
authors.forename: Sally C
authors.initials: SC
authors.lastname: Davies
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D004739:England; D005260:Female; D000068156:Formative Feedback; D058005:General Practitioners / Q000193:education*; D006801:Humans; D057970:Inappropriate Prescribing / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D010818:Practice Patterns, Physicians'; D066262:Social Norms; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents