[Validation of the Pollard' s classification criteria (2010) for rheumatoid arthritis patients with fibromyalgia]

To evaluate the sensitivity and specificity of Pollard' s classification criteria(2010) for the diagnosis of rheumatoid arthritis (RA) patients withfibromyalgia (FM) in Chinese patients, and to assess the clinical features and psychological status of RA-FM patients in a real-world observational setting.

Two hundred and two patients with rheumatoid arthritis were enrolled from the outpatients in Rheumatology and Immunology Department in Peking University People' s Hospital. All the patients were evaluated whether incorporating fibromyalgia translation occured using the 1990 American College of Rheumatolgy (ACR)-FM classification criteria. Forty two RA patients were concomitant with FM, while the other one hundred and sixty RA patients without FM were set as the control group.

There was no significant difference in general demography between the two groups (P>0.05). In this study, the Pollard' s classification criteria (2010) for RA-FM in Chinese patients had a high sensitivity of 95.2% and relatively low specificity of 52.6%. Compared with those patients without FM, RA patients with FM (RA-FM patients) had higher Disease Activity Scale in 28 joints (DAS-28) score (5.95 vs. 4.38, P=0.011) and much more 28-tender joint counts (TJC) (16.5 vs.4.5, P < 0.001).RA-FM patients had worse Health Assessment Questionnaire (HAQ) score (1.24 vs. 0.66, P < 0.001) and lower SF-36 (28.63 vs. 58.22, P < 0.001). Fatigue was more common in RA-FM patients (88. 1% vs. 50.6%, P < 0.001) and the degree of fatigue was significantly increased in RA-FM patients (fatigue VAS 5.55 vs. 3.55, P < 0.001). RA-FM patients also had higher anxiety (10 vs.4, P < 0.001) and depression scores (12 vs.6, P < 0.001). erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), morning stiffness time and 28-swollen joint counts (SJC) showed no difference between these two groups.

The Pollard' s classification criteria (2010) for RA-FM are feasible in Chinese rheumatoid arthritis patients. The Pollard' s classification criteria is highly sensitive in clinical application, while the relativelylow specificity indicates that various factors need to be considered in combination. RA patients with FM result in higher disease activity, worse function aland psychological status. RA patients with FM also have poorer quality of life. DAS-28 scores may be overestimated in RA patients with FM. In a RA patient thatdoes not reach remission, the possibility of fibromyalgia should be con-sidered.