Developing a provisional definition of flare in patients with established gout
Angelo L Gaffo, H Ralph Schumacher, Kenneth G Saag, William J Taylor, Janet Dinnella, Ryan Outman, Lang Chen, Nicola Dalbeth, Francisca Sivera, Janitzia Vázquez-Mellado, Chung-Tei Chou, Xuejun Zeng, Fernando Perez-Ruiz, Sergio C Kowalski, Claudia Goldenstein-Schainberg, Lan Chen, Thomas Bardin, Jasvinder A Singh, Angelo L Gaffo, H Ralph Schumacher, Kenneth G Saag, William J Taylor, Janet Dinnella, Ryan Outman, Lang Chen, Nicola Dalbeth, Francisca Sivera, Janitzia Vázquez-Mellado, Chung-Tei Chou, Xuejun Zeng, Fernando Perez-Ruiz, Sergio C Kowalski, Claudia Goldenstein-Schainberg, Lan Chen, Thomas Bardin, Jasvinder A Singh
Abstract
Objective: Various nonvalidated criteria for disease flare have been used in studies of gout. Our objective was to develop empirical definitions for a gout flare from patient-reported features.
Methods: Possible elements for flare criteria were previously reported. Data were collected from 210 gout patients at 8 international sites to evaluate potential gout flare criteria against the gold standard of an expert rheumatologist definition. Flare definitions based on the presence of the number of criteria independently associated with the flare and classification and regression tree approaches were developed.
Results: The mean ± SD age of the study participants was 56.2 ± 15 years, 207 of them (98%) were men, and 54 of them (26%) had flares of gout. The presence of any patient-reported warm joint, any patient-reported swollen joint, patient-reported pain at rest score of >3 (0-10 scale), and patient-reported flare were independently associated with the study gold standard. The greatest discriminating power was noted for the presence of 3 or more of the above 4 criteria (sensitivity 91% and specificity 82%). Requiring all 4 criteria provided the highest specificity (96%) and positive predictive value (85%). A classification tree identified pain at rest with a score of >3, followed by patient self-reported flare, as the rule associated with the gold standard (sensitivity 83% and specificity 90%).
Conclusion: We propose definitions for a disease flare based on self-reported items in patients previously diagnosed as having gout. Patient-reported flare, joint pain at rest, warm joints, and swollen joints were most strongly associated with presence of a gout flare. These provisional definitions will next be validated in clinical trials.
Copyright © 2012 by the American College of Rheumatology.
Source: PubMed