Serum homocysteine levels and their association with clinical characteristics of inflammatory arthritis.

OBJECTIVE: The aim of our study was to explore the serum levels of homocysteine (Hcy) and its association with clinical characteristics in patients with different types of inflammatory arthritis. METHODS: A total of 242 patients diagnosed with inflammatory arthritis (which included rheumatoid arthritis (RA), ankylosing spondylitis (AS), and gout), 49 with osteoarthritis (OA), and 36 with hyperuricaemia (HUA) and 81 healthy controls (HCs) were enrolled for comparisons. RESULTS: The serum Hcy levels of patients with RA, AS, and OA were comparable with those of the HC group (P > 0.05). However, the serum level of Hcy was significantly higher in patients with gout than in HCs (18.75 ± 9.98 vs. 14.20 ± 6.22 μmol/L, P = 0.007). In addition, we found that the serum Hcy level was much higher in RA patients who received methotrexate (MTX) therapy without folic acid supplementation than in those who received MTX with folic acid supplementation (13.39 ± 4.80 vs. 9.41 ± 2.04 μmol/L, P = 0.001). Furthermore, there was a positive correlation between uric acid and Hcy in patients without uric acid-lowering treatment (r = 0.537, P = 0.002), but the correlation was eliminated after adjusting uric acid-lowering treatment (r = 0.139, P = 0.393). Finally, consistent with the above findings, hyperhomocysteinaemia (HHcy) was more common in gout patients (P < 0.05). CONCLUSION: Screening for HHcy in patients with gout and RA, especially RA patients treated with MTX, might be necessary, and patients with HHcy might benefit from earlier supplementation with folic acid.Key Points•Serum homocysteine (Hcy) was elevated and the rate of hyperhomocysteinaemia (HHcy) was significantly higher in gout.•Rheumatoid arthritis (RA) patients who received methotrexate (MTX) treatment without folic acid supplementation showed higher serum Hcy than those who received MTX treatment with folic acid supplementation.•The serum Hcy level was positively correlated with age in only RA patients.•Serum Hcy was correlated with uric acid in gout patients, but the correlation was eliminated after adjusting uric acid-lowering treatment.