Clinical symptoms of rheumatoid arthritis (RA) improve in the course of the day, as can synovitis activity, reported via doppler ultrasound (US). The aim of the study was to establish whether the Color Doppler (CD) scores of synovitis in RA changes throughout the day.
In total, 27 patients with active RA, including 14 patients receiving corticosteroids were studied. US evaluation was performed twice in each patient, at 9 a.m. (T0) and after 4 p.m. (T1) on the same day by a single radiologist and using the same instrument. Overall, 30 joints were assessed, including grey scale and CD (S0 = no flow [no detectable CD)]; S1 = mild [CD <1/3 of the synovium]; S2 = moderate [CD <2/3]; S3 = pronounced [CD >2/3]).
In the total population, synovitis was detected more often in the evening than in the morning (39% vs. 33%, p = 0.02). The difference remained significant only in patients without corticosteroid administration (44% vs. 37%, p = 0.04). Moreover, a greater number of CD-positive joints were likewise found (S0 vs. S1 + S2 + S3) in the evening (57% vs. 51%, p = 0.04) in patients not receiving corticosteroids (67% vs. 41%, p = 0.002). More moderate (S2) and pronounced (S3) than mild (S1) synovitis was observed at T1 vs. T0 (39% vs. 24%, p = 0.03) in patients not receiving corticosteroids. More synovitis (40% vs 36% p = 0.02) in the dominant hand were found in the evening than in the morning.
Synovitis and CD activity increase during the day in RA patients, especially in joints of the dominant hands and in patients without corticosteroids.