Significance of asymptomatic hyperuricemia in ankylosing spondylitis

Abstract

Over the past decades, there has been an increase in the incidence of asymptomatic hyperuricemia (AHU), which includes an increased level (>360 μmol/L) of uric acid (UA) in the blood serum of patients with no clinical manifestations of gout. AHU is reported in various rheumatic diseases, mainly in osteoarthritis, in which AHU is one of the manifestations of the metabolic syndrome. There is relationship between AHU and pulmonary hypertension in systemic sclerosis, arterial hypertension (AH) in men with seronegative rheumatoid arthritis, extensive cutaneous psoriasis and metabolic disorders in psoriatic arthritis. There are almost no data on AHU in ankylosing spondylitis (AS), which served objective for this work.Objective: to assess the association of AHU with AS duration and activity and the presence of comorbid diseases.Patients and methods. A retrospective analysis of 48 medical histories of patients with diagnosed AS, who were treated in V.A. Nasonova Research Institute of Rheumatology from 2015 to 2019 years, whose serum UA level was >360 μmol/L.Results and discussion. More than half of patients with AS and AHU were overweight, 21% were obese. AH was diagnosed in 43.7% of patients. Stage II–III chronic kidney disease was detected in 16.7% of patients, urolithiasis – in 18.8%. 4 (8.3%) patients had diabetes mellitus. The serum UA level in patients with AS was 422.0 ± 61.6 μmol/L. In patients with AS, an association between AHU and age, duration and disease activity was noted. There was no statistically significant rela- tionship between HG and blood glucose, cholesterol, creatinine levels, body mass index. Correlation analysis revealed a statistically significant relationship between the glomerular filtration rate (GFR) and the age of patients (r=-0.54, p<0.001), the duration of the disease (r=-0.40, p<0.05), cholesterol level (r=-0.48, p=0.01), UA level (r=-0.45, p=0.03) and blood pressure (r=-0.54, p<0.001). There was no association between disease activity and GFR (p>0.05).Conclusion. In AS, an association between an increased level of UA in the blood serum and the duration and activity of the disease, and patient's age, was established.

Keywords

• uric acid
• asymptomatic hyperuricemia
• ankylosing spondylitis
• reactive arthritis
• psoriatic arthritis