Sally R Wilkes1, Hywel C Williams1, Anthony D Ormerod2, Fiona E Craig3, Nicola Greenlaw4, John Norrie5, Eleanor J Mitchell6, James M Mason7, Kim S Thomas8. 1. Center of Evidence-Based Dermatology, University of Nottingham, Nottingham, United Kingdom. 2. Division of Applied Medicine, Aberdeen University, Aberdeen, United Kingdom. 3. Department of Dermatology, Aberdeen Royal Infirmary, Aberdeen, United Kingdom. 4. Robertson Center for Biostatistics, University of Glasgow, Glasgow, United Kingdom. 5. Center for Healthcare Randomized Trials, Aberdeen University, Aberdeen, United Kingdom. 6. Nottingham Clinical Trials Unit, University of Nottingham, Nottingham, United Kingdom. 7. Warwick Medical School, University of Warwick, Coventry, United Kingdom. 8. Center of Evidence-Based Dermatology, University of Nottingham, Nottingham, United Kingdom. Electronic address: Kim.Thomas@nottingham.ac.uk.
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. LIMITATIONS: We were limited by data available from existing datasets. CONCLUSION: Speed of healing, IGA, and resolution of inflammation were all shown to be good predictors of eventual healing of pyoderma gangrenosum.
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. LIMITATIONS: We were limited by data available from existing datasets. CONCLUSION: Speed of healing, IGA, and resolution of inflammation were all shown to be good predictors of eventual healing of pyoderma gangrenosum.
Authors: Emily Patsko; Peter J Godolphin; Kim S Thomas; Trish Hepburn; Eleanor J Mitchell; Fiona E Craig; Philip M Bath; Alan A Montgomery Journal: Trials Date: 2017-02-02 Impact factor: 2.279