To investigate the predictive value of synovitis detected by Doppler US in relation to failed tapering of biologic therapy (BT) in RA patients in sustained clinical remission.
A total of 77 RA patients (52 women, 25 men) in sustained clinical remission, treated with a stable dosage of BT were prospectively recruited. BT was tapered according to an agreed strategy implemented in clinical practice (i.e. increasing the interval between doses for s.c. BT and reducing the dose for i.v. BT). BT tapering failure was assessed at 6 and 12 months. Doppler US investigation of 42 joints for the presence and grade (0-3) of B-mode synovial hypertrophy and synovial power Doppler signal (i.e. Doppler synovitis) was performed at baseline by a rheumatologist blinded to clinical and laboratory data. Hand and foot radiographs were obtained at baseline and at 12-month follow-up.
Of the 77 patients, 46 (59.7%) were on s.c. BT and 31 (40.3%) on i.v. BT. At 12 months, 35 patients (45.5%) presented BT tapering failure, 23 of them (29.9% of all patients) in the first 6 months of BT tapering. In logistic regression analysis, the baseline DAS28 and the global score of Doppler synovitis were identified as independent predictors of BT tapering failure at 12 and 6 months. The presence of Doppler synovitis was the strongest predictor for BT tapering failure. No patient showed radiographic progression.
Our results suggest that the presence of Doppler-detected synovitis may predict BT tapering failure in RA patients in sustained clinical remission.