Ultrasound to identify SLE patients with musculoskeletal symptoms who respond best to therapy: The USEFUL longitudinal multicentre study.

Objective To determine whether SLE patients with inflammatory joint symptoms and ultrasound-synovitis/tenosyovitis achieve better clinical responses to glucocorticoid compared with patients with normal scans. Secondary objectives included identification of clinical features predicting ultrasound-synovitis/tenosynovitis. Methods In a longitudinal muticentre study, SLE patients with physician-diagnosed inflammatory joint pain received intramuscular methylprednisolone 120 mg once. Clinical assessments, patient-reported outcomes, and bilateral hands/wrist ultrasound were collected at 0-, 2- and 6-weeks. The primary outcome (determined via internal pilot) was early morning stiffness visual analogue scale (EMS-VAS) at 2-weeks, adjusted for baseline, comparing patients with positive (Grey-scale ≥2 and/or Power-Doppler ≥1) and negative ultrasound. Post-hoc analyses excluded fibromyalgia. Results Of 133 patients, 78 had positive ultrasound. Only 53/78 (68%) of these had ≥1 swollen joint. Of 66/133 patients with ≥1 swollen joint, 20% had negative ultrasound. Positive ultrasound was associated with joint swelling, symmetrical small joint distribution and serology. The primary end point was not met: in the full analysis set (n = 133) there was no difference in baseline-adjusted EMS-VAS at week-2 (-7.7 mm 95% CI -19.0 mm, 3.5 mm, p= 0.178). After excluding 32 patients with fibromyalgia, response was significantly better in patients with positive ultrasound at baseline (baseline-adjusted EMS-VAS at 2-weeks -12.1 mm, 95% CI -22.2 mm, -0.1 mm, p= 0.049). This difference was greater when adjusted for treatment (-12.8 mm (95% CI -22mm, -3mm), p= 0.007). BILAG and SLEDAI responses were higher in ultrasound-positive patients. Conclusions In SLE patients without fibromyalgia, those with positive ultrasound had better clinical response to therapy. Imaging-detected synovitis/tenosynovitis may be considered to decide on therapy and enrich clinical trials.