Association of serum uric acid with clinical and radiological severity of knee osteoarthritis in non-gouty patients

Abstract

Background: A growing body of evidence suggested that uric acid (UA) may contribute in the pathways underlying osteoarthritis (OA) pathogenesis; however, studies that investigated the relationship between UA and OA emerged inconclusive results. The purpose of the study was to explore the association of serum uric acid (sUA) levels with clinical severity, radiological severity of knee osteoarthritis (KOA) based on Kellgren-Lawrence (KL) grading system, and MRI changes in non-gouty patients. Results: WOMAC scores: pain, stiffness, function, and total score are significantly higher in H-sUA group than L-sUA group (p = 0.004, p = 0.019, p = 0.018, p = 0.008 respectively). Joint space width (JSW) is significantly narrower in H-sUA group than L-sUA group (p = 0.013). H-sUA group had more frequent KL grade 4 (p < 0.001), osteophytes grade 4 (p < 0.001), focal bone erosion (p < 0.001), bone marrow lesions (p = 0.023), and synovitis (p = 0.011) than L-sUA group. Female KOA patients in H-sUA group had significantly higher pain, stiffness, and function and total WOMAC scores than L-sUA group (p = 0.003, p = 0.015, p = 0.008, p = 0.004), more frequently had KL grade 4 and osteophytes grade 4 (p = 0.003, p < 0.001), significantly narrower JSW (p = 0.016), more frequently show focal bone erosion (p = 0.002), bone marrow lesions (p = 0.019), and synovitis (p = 0.004) than L-sUA group. In regression analysis, female sex (p = 0.035), duration of KOA (p = 0.031), and sUA level (p = 0.025) were associated with KL severity. For female patients with KOA, KL severity is associated with duration of KOA (p = 0.045) and sUA (p = 0.009). Conclusion: Higher sUA level is associated with higher clinical severity, higher radiographic KL grades, and more frequent MRI findings in patients with primary KOA patients. Our results also indicated that sUA level was significantly associated with KOA severity in female patients, but not in male patients. More studies are warranted to explore whether the two conditions exist simultaneously or there is a direct causal relationship between the two conditions.