The association of power doppler signal with DAS 28 in patients presenting arthritic symptoms

Abstract

Objective: To examine the relationship between power Doppler ultrasonography (PDUS) parameters with the disease activity grade reflected by the 28 joint Disease Activity Score (DAS 28) in patients presenting arthritic symptoms. Methods: Thirty-three patients with inflammatory arthritis features were consequently enrolled in the study. The PDUS exam of target joints, measurements of DAS 28 and its components (tender joint count, swollen joint count, ESR, CRP, and Patient Global Visual Analogue Scale) were conducted on every 4 week interval visits, until the initially detected Doppler signal disappeared in target joints. Total 80 visit data was gathered and analyzed accordingly in this study. Pearson’s correlation coefficients were represented to reveal the relationship between the PDUS parameters and DAS 28. Then, the total study population was divided into two groups, rheumatoid arthritis (RA) group and non-RA group. The same statistical analysis process was performed in each group, and the results were evaluated and compared each other. Results: The correlation between the sum of power Doppler semi-quantitative grade of target joints (sum of PD grade) and DAS 28 assessed at each follow up visit was 0.59 by the Pearson correlation coefficient (P<0.0001). The Pearson correlation coefficient between the sum of power Doppler quantitative analysis area (sum of PD area) and DAS 28 was 0.61 (P<0.0001). In the RA group, the Pearson correlation coefficients became higher between the PDUS parameters and DAS 28 (r=0.60, P<0.0001 for PDUS grade. r=0.63, P<0.0001 for PDUS area.). On the contrary, the correlation became weaker between PDUS parameters and DAS 28 in non-RA group. Pearson correlation coefficients between the sum of PD grade and DAS 28 was 0.56 (P=0.0031), and Pearson correlation coefficient between the sum of PD area and DAS 28 was 0.57 (P = 0.0038) in non-RA group. Conclusions: Our study data showed significantly high correlation between PDUS parameters and DAS 28. These results support that the PDUS technique is reliable tool for determining the activity of synovitis in daily clinical practice.