Association between hyperuricemia and ultrasound-detected hand synovitis.

OBJECTIVE: Although hand synovitis is prevalent in the older population, the aetiology remains unclear. Hyperuricemia, a modifiable metabolic disorder, may serve as an underlying mechanism of hand synovitis, but little is known about their relationship. We assessed the association between hyperuricemia and hand synovitis in a large population-based sample.

METHODS: We performed a cross-sectional study in Longshan County, Hunan Province, China. Hyperuricemia was defined as a serum urate >420 μmol/L in men and >360 μmol/L in women. Ultrasound examinations were performed on both hands of 4,080 participants, and both grey-scale synovitis and Power Doppler signal (PDS) were assessed using semiquantitative scores (grades 0-3). We evaluated the association of hyperuricemia with hand grey-scale synovitis (grade ≥2) and PDS (grade ≥1), respectively, adjusting for age, sex and body mass index.

RESULTS: All required assessments for analysis were available on 3,286 participants. The prevalence of hand grey-scale synovitis was higher among participants with hyperuricemia (30.0%) than those with normouricemia (23.3%), with an adjusted odds ratio (aOR) of 1.28 (95% confidence interval [CI]:1.00-1.62). Participants with hyperuricemia also had higher prevalence of PDS (aOR=2.36, 95% CI:1.15-4.81). Furthermore, hyperuricemia positively associated, both at the hand and joint levels, with presence of grey-scale synovitis (aOR=1.27, 95% CI:1.00-1.60, and adjusted prevalence ratio [aPR]=1.26, 95% CI:1.10-1.44, respectively), and PDS (aOR=2.35, 95% CI:1.15-4.79, and aPR=2.34, 95% CI:1.28-4.30, respectively).

CONCLUSION: This population-based study provides more evidences for a positive association between hyperuricemia and prevalent hand synovitis.