Electrical stimulation shows promise in erosive hand osteoarthritis

The use of transcutaneous auricular vagus nerve stimulation (taVNS) in patients with erosive hand osteoarthritis is safe and well tolerated and may potentially relieve pain, particularly in those with greater synovial inflammation, according to the sham-controlled ESTIVAL trial.

ESTIVAL included 142 adult patients (mean age 66.5 years, 88 percent female) who fulfilled the American College of Rheumatology criteria for hand osteoarthritis and had at least one erosive interphalangeal joint and ultrasound-confirmed synovitis.

The patients were randomly assigned to receive daily 20-min treatment sessions with taVNS (n=73) or sham stimulation (no electrical current; n=69) for 12 weeks. The primary endpoint was hand pain, measured on a visual analogue scale (VAS). Safety was also assessed.

Primary outcome data at week 12 were available for 63 patients (86 percent) in the taVNS group and 64 (93 percent) in the sham group. The study did not meet the primary endpoint, with the change in hand pain at week 12 not significantly different between the taVNS and sham groups (median, –16 vs –6 mm; adjusted difference, –10 mm, 95 percent confidence interval, –23 to 2; p=0.22).

However, consistent pain reduction was observed with taVNS vs sham in the subgroup of patients with greater synovial inflammation.

Adverse events occurred in 22 (30 percent) patients in the taVNS group and in 16 (23 percent) in the sham group, with no emerging safety concerns. There were no serious adverse events documented.