Ultrasound7 versus ultrasound12 in monitoring the response to infliximab in patients with rheumatoid arthritis

This study aimed to assess the responsiveness of ultrasonography (US)-7 in patients with rheumatoid arthritis (RA). Eighty-two RA patients were recruited and followed up for 22 weeks. The clinical, laboratory, and X-ray assessments, along with grayscale US (GSUS) and power Doppler US (PDUS) examinations were performed at baseline, 6, 14, and 22 weeks after infliximab treatment. GSUS for synovitis and PDUS for synovitis and paratendinitis/tenosynovitis were assessed by a semi-quantitative (0 to 3) score, while GSUS for paratendinitis/tenosynovitis and bone erosion was qualitatively assessed as absent or present (0 or 1). US scores in both 7-joint (US7) and 12-joint (US12) systems were evaluated. After 6, 14, and 22 weeks of treatment with infliximab, indices such as US scores, 28-joint disease activity (DAS28) score, and tender and swelling joint count were all significantly improved compared to baseline. US7 scores were significantly correlated with that of US12. Strong correlations were identified between most US7 scores with DAS28, health assessment questionnaire (HAQ), and C-reactive protein (CRP) levels. When DAS28 was used as a reference, the US7 cutoff for disease remission was less than 35 for GS + PD and also less than 29 for GS and 1 for PD, respectively. Additionally, the positive percent agreement, negative percent agreement, and overall percent agreement for GS + PD were 77.78, 76.19, and 76.67 %, respectively, which were all higher than that of GS or PD. US7 may be a feasible tool to assess the therapeutic response in RA patients.