Chief Medical Officers Can Reduce Antibiotic Prescribing

Reviewed by Rupak Datta, MD PhD, Yale School of Medicine

Following a randomized controlled trial demonstrating that a letter from England’s Chief Medical Officer (CMO) can reduce antibiotic prescribing,1 the effectiveness of repeated letters from the CMO was evaluated among physician practices whose antibiotic prescribing was in the top 20% nationally (n=1439) relative to a control group (n=5986).  Physicians in the intervention group were sent a letter from the CMO stating, ‘the great majority of practices in England prescribe fewer antibiotics per head than yours’ whereas physicians in the control group received no communication.  In regression discontinuity analysis, physician practices that received the letter changed their prescribing rates by -3.69% (95% CI: -2.29, -5.10) over a 6-month period, representing approximately 124,952 fewer antibiotics dispensed.2  The authors conclude that social norm feedback from a high-profile messenger continues to be effective when repeated.


  • Hallsworth M, Chadborn T, Sallis A, et al. Provision of social norm feedback to high prescribers of antibiotics in general practice: a pragmatic national randomised controlled trial. Lancet. 2016;387(10029):1743-1752.
  • Ratajczak M, Gold N, Hailstone S, Chadborn T. The effectiveness of repeating a social norm feedback intervention to high prescribers of antibiotics in general practice: a national regression discontinuity design. Journal of Antimicrobial Chemotherapy. 2019;74(12):3603-3610.
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