Serum Urate Levels Predict Joint Space Narrowing in Non-Gout Patients With Medial Knee Osteoarthritis

Svetlana Krasnokutsky, Charles Oshinsky, Mukundan Attur, Sisi Ma, Hua Zhou, Fangfei Zheng, Meng Chen, Jyoti Patel, Jonathan Samuels, Virginia C. Pike, Ravinder Regatte, Jenny Bencardino, Leon Rybak, Steven Abramson, Michael H. Pillinger

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Objective: The pathogenesis of osteoarthritis (OA) includes both mechanical and inflammatory features. Studies have implicated synovial fluid uric acid (UA) as a potential OA biomarker, possibly reflecting chondrocyte damage. Whether serum UA levels reflect/contribute to OA is unknown. We investigated whether serum UA levels predict OA progression in a non-gout knee OA population. Methods: Eighty-eight patients with medial knee OA (body mass index [BMI] <33 kg/m2) but without gout were studied. Baseline serum UA levels were measured in previously banked serum samples. At 0 and 24 months, patients underwent standardized weight-bearing fixed-flexion posteroanterior knee radiography to determine joint space width (JSW) and Kellgren/Lawrence grades. Joint space narrowing (JSN) was calculated as the change in JSW from 0 to 24 months. Twenty-seven patients underwent baseline contrast-enhanced 3T knee magnetic resonance imaging for assessment of synovial volume. Results: Serum UA levels correlated with JSN values in both univariate (r = 0.40, P < 0.01) and multivariate (r = 0.28, P = 0.01) analyses. There was a significant difference in mean JSN after dichotomization at a serum UA cut point of 6.8 mg/dl, the solubility point for serum urate, even after adjustment (JSN of 0.90 mm for a serum UA ≥6.8 mg/dl and 0.31 mm for a serum UA <6.8 mg/dl; P < 0.01). Baseline serum UA levels distinguished progressors (JSN >0.2 mm) and fast progressors (JSN >0.5 mm) from nonprogressors (JSN ≤0.0 mm) in multivariate analyses (area under the receiver operating characteristic curve 0.63 [P = 0.03] and 0.62 [P = 0.05], respectively). Serum UA levels correlated with the synovial volume (r = 0.44, P < 0.01), a possible marker of JSN, although this correlation did not persist after controlling for age, sex, and BMI (r = 0.13, P = 0.56). Conclusion: In non-gout patients with knee OA, the serum UA level predicted future JSN and may serve as a biomarker for OA progression.

Original languageEnglish (US)
Pages (from-to)1213-1220
Number of pages8
JournalArthritis and Rheumatology
Volume69
Issue number6
DOIs
StatePublished - Jun 2017
Externally publishedYes

Bibliographical note

Funding Information:
The authors thank Chio Yokose, Aaron Garza, and Rochelle Yates.

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