Background/Purpose

To estimate the prevalence of subclinical synovitis detected by ultrasound in rheumatoid arthritis (RA) and psoriatic arthritis (PsA) patients in clinical remission receiving anti-TNFα therapy with extended interval of administration (EIA).

Methods

Prospective observational study. Population: Patients diagnosed with RA and PsA, being in clinical remission and receiving anti-TNFα therapy with EIA. 12-joint ultrasound assessment (elbows, wrists, 2nd and 3rd metacarpo-phalangeal, knees and ankles) (Naredo E. Arthritis Rheum 2008,59:515-22) was performed (MyLab 25 Esaote s.p.a, Firenze, Italy), evaluating synovitis through B-mode (BM) and Color Doppler signal (CD), both by semiquantitative scale from 0 to 3 points. Subsequently, a BM and CD score was calculated, summing the highest score obtained from any one of the synovial sites evaluated at each joint to a maximum of 36 points. The sonographer was blinded to the clinical and laboratory data.

Results

26 patients were included in the study, 76.9% were women, mean age was 59 years [31-79] and mean duration of disease was 14 years [3-46]. The diagnosis was RA in 24 patients (92%) and APs in 2 (7%). In 83% of RA patients rheumatoid factor was positive, and in 79% the citrullinated protein antibody was positive. Ultrasound assessment prior to EIA was available in 17 patients. Clinical activity and ultrasound scores are summarized in Table 1. Ultrasound detects some synovitis by CD in 50% of EIA patients, and by BM in 96% of EIA patients. Nevertheless most of them had a low CD score (average 1.42 out of 36 points). No statistically significant differences were found when comparing prior and after EIA clinical and ultrasound scores (data not shown). The mean time from the beginning of EIA was 15 months (range 1 to 48 months). The EIA treatments were etanercept (ETN) in 14 patients and adalimumab (ADA) in 12 patients, with the following patterns: ETN/10 days (11 pat.), ETN/14 days (3 pat.), ADA/18 days (1 pat.), ADA/21 days (10 pat.), ADA/30 days (1 pat.). 10 patients (not included in the study) never began EIA due to clinical decision, and 7 (27%) had to return to the standard administration pattern due to worsening of disease activity.

Table 1. Clinical and ultrasound scores
	Prior to EIA ultrasound	After EIA ultrasound
n	17	26
DAS28-VSG, mean [range]	1.55 [0.63–2.64]	1.74 [0.51–4.06]
DAS28-PCR, mean [range]	1.69 [1.13–2.89]	1.75 [1.13–3.38]
SDAI, mean [range]	3.58 [2.10–10.10]	4.05 [2.10–16.1]
CDAI, mean [range]	3.35 [2–10]	3.92 [2–16]
Color Doppler score >0, n (%)	12 (70.6%)	13 (50.0%)
Color Doppler score, mean [range]	1.06 [0–3]	1.42 [0–5]
B-mode SH score >0, n (%)	14 (82.4%)	25 (96.2%)
B-mode SH score, mean [range]	4.18 [0–19]	4.46 [0–17]

EIA: Extended interval of administration of anti-TNFα; DAS28: Disease Activity Score in 28 joints; SDAI: Simplified Disease Activity Index; CDAI: Clinical Disease Activity Index; SH: synovial hypertrophy.

Conclusion

Some synovitis was detected by Color Doppler ultrasound in 50% of patients in clinical remission receiving anti-TNFα therapy with extended interval of administration. Most of them had a low Color Doppler ultrasound score. Synovial hypertrophy was detected by B-mode ultrasound in 96% of them. No statistically significant differences were found when comparing prior and after EIA clinical and ultrasound scores.

Acknowledgements: This work was supported by a grant from Fundación Española de Reumatología.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/prevalence-of-subclinical-synovitis-detected-by-ultrasound-in-rheumatoid-arthritis-and-psoriatic-arthritis-patients-receiving-anti-tnf-%ce%b1-therapy-with-extended-interval-of-administration/