Background Combined indices for the assessment of rheumatic diseases like the DAS28 or the HAQ are inappropriate to detect activity alterations in single joints. Intraarticular treatment of single active joints, however, is a useful and increasingly performed procedure for mon- or oligoarthritis in otherwise controlled inflammatory polyarthritis.
Objectives To validate a recently established PRO-based assessment instrument (1) for patients with inflammatory arthritis, who received intraarticular glucocorticoid injections in a single inflamed joint by comparing the performance of the PRO with validated combined indices for disease activity (DAS28) and functional capacity (HAQ) and high sensitivity ultrasound examination as the gold standard for the detection of synovitis.
Methods 54 patients with polyarticular joint disease (47 rheumatoid arthritis, 4 psoriatic arthritis, 3 others) on otherwise successful treatment with disease modifying antirheumatic drugs and/or TNF inhibitors but significant inflammation in a single joint were assessed by clinical examination, serologically (ESR), grey scale (GS) and power doppler (PD) ultrasound, DAS28, HAQ and PROs before the intraarticular injection (baseline, BL) and at time points week 1 (follow-up 1, FU1) and 4 (FU2). Ultrasound findings were scored semiquantitatively (grade 0-3) as described (2). PROs consisted of 3 questions about the global status, and the function and pain in the affected joint on 100 mm visual analogue scales. Pearson’s rank correlation was used for comparison between PROs, HAQ and DAS28 and Spearman’s rank correlation was used for comparison between semiquantitative ultrasound results and PRO.
Results The mean DAS28 was low with 3.30 at BL and showed an insignificant decrease to 2.62 at FU2. The HAQ showed little functional impairment with a mean of 0.94 at BL and minor changes upon treatment to 0.67 at FU2. PD and GS scores of the active joint decreased significantly at both follow up examinations, with the most pronounced response seen in PD ultrasonography. Mean ESR was 15.4 at BL and 11.6 at FU2. The three PRO questions showed median values of 68.0, 70.0 and 64.0 at BL, but decreased dramatically to 19.0, 26.0, and 21.0 at FU1 and remained stable with 16.0, 29.0 and 6.0 at FU2. There was a modest but significant correlation between the PRO and the HAQ at any time (p<0.01) and at BL and FU2 between the DAS28 and the PRO question 3 concerning the pain (p<0.01). All three PRO questions correlated well with each other at any time. In addition at FU2, the PRO correlated well with GS ultrasound results (p<0.01 for questions about global status and pain).
Conclusions PROs on global status, function and pain are valuable and reliable tools for the assessment of single joint treatment: As they correlate well with ultrasound evaluation, they are valuable tools for the assessment of single joint activity and the clinical efficacy of intraarticular treatment. In sharp contrast, combined indices (e.g. DAS28) and global functional questionnaires (e.g. HAQ) are of minor relevance in this clinical situation and, thus, dispensable.
Heald AE et al., J Rheumatol 2010;37(5):1042
Backhaus M et al., Arthritis Rheum 2009;61(9):1194
Disclosure of Interest None Declared
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