Evaluation of composite measures of treatment response without acute-phase reactants in patients with rheumatoid arthritis.
OBJECTIVE
To evaluate composite measures of response without acute-phase reactants in RA patients. Specifically, Clinical Disease Activity Index (CDAI)-derived response criteria were compared with the European League Against Rheumatism (EULAR) response criteria, and the modified ACR (mACR) response criteria were compared to the ACR response criteria.


METHODS
Data from 10 108 RA patients enrolled in the Consortium of Rheumatology Researchers of North America registry were examined, including 649 patients initiating DMARD therapy. CDAI cut-off points for disease activity levels and responses were derived using receiver operating characteristic curves with the DAS28 and EULAR response criteria as gold standards. The kappa-statistics were applied to assess agreement between CDAI-derived and EULAR-defined responses, as well as ACR20 and ACR50 with mACR20- and mACR50-defined responses, respectively.


RESULTS
For the components of the EULAR response, the derived CDAI cut-off points for DAS28 levels of 3.2 and 5.1 were 7.6 and 19.6, respectively. The derived CDAI cut-off points were 4.3 and 10.0 for DAS28 changes of 0.6 and 1.2, respectively. There were moderate to substantial agreements between CDAI-derived and EULAR responses (kappa = 0.57-0.71). Agreement of ACR20 and ACR50 with mACR20 and mACR50 responses, respectively, was excellent (kappa = 0.88-0.95).


CONCLUSIONS
Agreement between composite measures of response without acute-phase reactants and standard measures ranged from moderate to excellent. The mACR20 and mACR50 criteria as well as CDAI-derived response criteria, can serve as composite measures of response in clinical practice and research settings without access to acute-phase reactants.
Greenberg
Jeffrey D
JD
Department of Rheumatology, New York University Hospital for Joint Diseases, New York, NY 10003, USA. jeffrey.greenberg@nyumc.org
Harrold
Leslie R
LR
Bentley
Mary J
MJ
Kremer
Joel
J
Reed
George
G
Strand
Vibeke
V
D000208:Acute Disease; D000368:Aged; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000276:immunology / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012042:Registries; D012219:Rheumatology; D012720:Severity of Illness Index; D016896:Treatment Outcome
D018501:Antirheumatic Agents