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Is speed of healing a good predictor of eventual healing of pyoderma gangrenosum?

Wilkes, Sally R.; Williams, Hywel C.; Ormerod, Anthony D.; Craig, Fiona E.; Greenlaw, Nicola; Norrie, John; Mitchell, Eleanor; Mason, James M.; Thomas, Kim S.


Sally R. Wilkes

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Professor of Dermato-Epidemiology

Anthony D. Ormerod

Fiona E. Craig

Nicola Greenlaw

John Norrie

James M. Mason


Background: Pyoderma gangrenosum is a rare inflammatory skin condition. The STOPGAP studies compared 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 three early predictors for healing at 6 months - speed of healing, Investigator Global Assessment and resolution of inflammation, recorded at 2 and 6 weeks.
Methods: Logistic regression models were applied and the effectiveness of the three measures was assessed through estimating the positive (PPV) and negative predictive values (NPV) and the area under the receiver operating characteristic curve (AUC).
Results: The PPV and NPV at 6 weeks were 63.5% (95% CI:52.4%, 73.7%) and 74.6% (95% CI:62.5%, 84.5%) respectively for speed of healing; 80% (95% CI:68.7%, 88.6%) and 74.2% (95% CI:64.1%, 2.7%) for IGA; and 72.1% (95% CI:59.9%, 82.3%) and 68.1% (95% CI:57.7%, 77.3%) for resolution of inflammation. Investigator Global Assessment had the best combined PPV, NPV and AUC at 2 and 6 weeks.
Limitations: We were limited by data available from the STOP GAP trial and cohort study.
Conclusion: Speed of healing, Investigator Global Assessment and resolution of inflammation were all shown to be good predictors of eventual healing.


Wilkes, S. R., Williams, H. C., Ormerod, A. D., Craig, F. E., Greenlaw, N., Norrie, J., …Thomas, K. S. (2016). Is speed of healing a good predictor of eventual healing of pyoderma gangrenosum?. Journal of The American Academy of Dermatology, 75(6), 1216-1220.e2.

Journal Article Type Article
Acceptance Date Jul 25, 2016
Online Publication Date Oct 11, 2016
Publication Date 2016-12
Deposit Date Jul 28, 2016
Publicly Available Date Oct 11, 2016
Journal Journal of the American Academy of Dermatology
Print ISSN 0190-9622
Electronic ISSN 1097-6787
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 75
Issue 6
Article Number 1216-1220.e2
Pages 1216-1220.e2
Keywords Pyoderma Gangrenosum, Speed of Healing, Lesion Improvement, Resolution of Inflammation, Predictors, Clinical Trials, Clinical Practice
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Mediated Deposit Request -Date of acceptance 25 07 2016 (002).pdf (923 Kb)

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