title: Prophylactic antibiotics to prevent cellulitis of the leg: economic analysis of the PATCH I & II trials.
abstract: BACKGROUND
  Cellulitis (erysipelas) is a recurring and debilitating bacterial infection of the skin and underlying tissue. We assessed the cost-effectiveness of prophylactic antibiotic treatment to prevent the recurrence of cellulitis using low dose penicillin V in patients following a first episode (6 months prophylaxis) and more recurrent cellulitis (12 months prophylaxis, or 6 months in those declining 12 months).
  
  
  METHODS
  Within-trial cost-effectiveness analysis was conducted using the findings of two randomised placebo-controlled multicentre trials (PATCH I and PATCH II), in which patients recruited in the UK and Ireland were followed-up for up to 3 years. Incremental cost, reduction in recurrence, cost per recurrence prevented and cost/QALY were estimated. National unit and reference costs for England in 2010 were applied to resource use, exploring NHS and societal perspectives. A total of 397 patients from the two trials contributed to the analysis.
  
  
  RESULTS
  There was a 29% reduction in the number of recurrences occurring within the trial (IRR: 0.71 95%CI: 0.53 to 0.90, p = 0.02), corresponding to an absolute reduction of recurrence of 0.31 recurrences/patient (95%CI: 0.05 to 0.59, p = 0.02). Incremental costs of prophylaxis suggested a small cost saving but were not statistically significant, comparing the two groups. If a decision-maker is willing to pay up to £25,000/QALY then there is a 66% probability of antibiotic prophylaxis being cost-effective from an NHS perspective, rising to 76% probability from a secondary, societal perspective.
  
  
  CONCLUSIONS
  Following first episode or recurrent cellulitis of the leg, prophylactic low dose penicillin is a very low cost intervention which, on balance, is effective and cost-effective at preventing subsequent attacks. Antibiotic prophylaxis reduces cellulitis recurrence by nearly a third but is not associated with a significant increase in costs.
authors.affiliation: Durham Clinical Trials Unit, Durham University, Queen's Campus, Stockton-on-Tees, United Kingdom.
authors.forename: James M
authors.initials: JM
authors.lastname: Mason
authors.affiliation: Centre of Evidence-Based Dermatology, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Kim S
authors.initials: KS
authors.lastname: Thomas
authors.affiliation: Medical Research Council Clinical Trials Unit, London, United Kingdom.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Crook
authors.affiliation: Centre of Evidence-Based Dermatology, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Katharine A
authors.initials: KA
authors.lastname: Foster
authors.affiliation: Centre of Evidence-Based Dermatology, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Joanne R
authors.initials: JR
authors.lastname: Chalmers
authors.affiliation: Medical Research Council Clinical Trials Unit, London, United Kingdom.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Nunn
authors.affiliation: Centre of Evidence-Based Dermatology, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Hywel C
authors.initials: HC
authors.lastname: Williams
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000191:economics* / Q000494:pharmacology / Q000627:therapeutic use*; D019072:Antibiotic Prophylaxis / Q000191:economics*; D002481:Cellulitis / Q000188:drug therapy* / Q000191:economics / Q000517:prevention & control*; D003362:Cost-Benefit Analysis; D003365:Costs and Cost Analysis; D005260:Female; D006801:Humans; D007866:Leg / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D055502:Secondary Prevention; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents