title: Is speed of healing a good predictor of eventual healing of pyoderma gangrenosum?
abstract: BACKGROUND
  Pyoderma gangrenosum is a rare inflammatory skin condition. Two prospective studies have evaluated treatments for pyoderma gangrenosum using a primary outcome of healing speed at 6 weeks.
  
  
  OBJECTIVE
  Using data from both studies we assessed the predictive value of 3 early predictors for healing at 6 months: speed of healing, Investigator Global Assessment (IGA), and resolution of inflammation, recorded at 2 and 6 weeks.
  
  
  METHODS
  Logistic regression models were applied and the effectiveness of the 3 measures was assessed through estimating the positive and negative predictive values and the area under the receiver operating characteristic curve.
  
  
  RESULTS
  The positive and negative predictive value at 6 weeks were, respectively, 63.5% (95% confidence interval [CI] 52.4%-73.7%) and 74.6% (95% CI 62.5%-84.5%) for speed of healing; 80% (95% CI 68.7%-88.6%) and 74.2% (95% CI 64.1%-82.7%) for IGA; and 72.1% (95% CI 59.9%-82.3%) and 68.1% (95% CI 57.7%-77.3%) for resolution of inflammation. IGA had the best combined positive predictive value, negative predictive value, and area under the receiver operating characteristic curve at 2 and 6 weeks.
  
  
  CONCLUSIONS
  We were limited by data available from existing datasets.
  
  
  CONCLUSIONS
  Speed of healing, IGA, and resolution of inflammation were all shown to be good predictors of eventual healing of pyoderma gangrenosum.
authors.affiliation: Center of Evidence-Based Dermatology, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Sally R
authors.initials: SR
authors.lastname: Wilkes
authors.affiliation: Center of Evidence-Based Dermatology, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Hywel C
authors.initials: HC
authors.lastname: Williams
authors.affiliation: Division of Applied Medicine, Aberdeen University, Aberdeen, United Kingdom.
authors.forename: Anthony D
authors.initials: AD
authors.lastname: Ormerod
authors.affiliation: Department of Dermatology, Aberdeen Royal Infirmary, Aberdeen, United Kingdom.
authors.forename: Fiona E
authors.initials: FE
authors.lastname: Craig
authors.affiliation: Robertson Center for Biostatistics, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Nicola
authors.initials: N
authors.lastname: Greenlaw
authors.affiliation: Center for Healthcare Randomized Trials, Aberdeen University, Aberdeen, United Kingdom.
authors.forename: John
authors.initials: J
authors.lastname: Norrie
authors.affiliation: Nottingham Clinical Trials Unit, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Eleanor J
authors.initials: EJ
authors.lastname: Mitchell
authors.affiliation: Warwick Medical School, University of Warwick, Coventry, United Kingdom.
authors.forename: James M
authors.initials: JM
authors.lastname: Mason
authors.affiliation: Center of Evidence-Based Dermatology, University of Nottingham, Nottingham, United Kingdom. Electronic address: Kim.Thomas@nottingham.ac.uk.
authors.forename: Kim S
authors.initials: KS
authors.lastname: Thomas
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D023381:Endpoint Determination; D005260:Female; D006801:Humans; D007249:Inflammation / Q000188:drug therapy / Q000209:etiology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D017511:Pyoderma Gangrenosum / Q000150:complications / Q000188:drug therapy*; D012372:ROC Curve; D016032:Randomized Controlled Trials as Topic; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D014945:Wound Healing
keywords: clinical practice; clinical trials; lesion improvement; predictors; pyoderma gangrenosum; resolution of inflammation; speed of healing