Correction of vitamin D deficiency in patients with gout receiving febuxostat (pilot study)

Objective. To evaluate the effect of correcting vitamin D deficiency on uricemia, inflammation, and parathyroid function in patients with gout receiving febuxostat.Material and methods. This prospective observational study included 79 patients with gout who had been receiving febuxostat at adequate doses for ≥2 weeks. Serum levels of uric acid (UA), parathyroid hormone (PTH), vitamin D, and C-reactive protein (CRP) were measured in all patients. In cases of vitamin D deficiency (25(OH)D <30 ng/ml), patients were advised to take cholecalciferol 4000 IU/day for 3 months. The dynamics of these parameters were then assessed in patients who received cholecalciferol (Group 1) and those with normal vitamin D levels (Group 2).Results and discussion. In 65 (83%) of 79 patients, serum UA level was <360 μmol/L; febuxostat dose ranged from 40 to 120 mg/day. In 63 (80%) patients, 25(OH)D level was <30 ng/ml; of these, 19 (30%) received cholecalciferol (Group 1). After treatment, the level of 25(OH)D increased (p=0.0013), and level of PTH decreased (p=0.0077). Changes in serum UA were comparable between groups (p=0.72). No correlation was found between Δ vitamin D and Δ UA in patients with vitamin D deficiency (r= -0.26, p>0.05). In Group 1, the median Δ CRP was significantly greater than in Group 2 (p=0.027). The number of patients with CRP >2 mg/L in Group 1 decreased from 11 (58%) to 5 (26%) (p=0.049).Conclusion. Correction of vitamin D deficiency in gout patients receiving optimal urate-lowering therapy reduces CRP levels but does not affect serum UA. For a substantial proportion of patients, a febuxostat dose of 40 mg/day is sufficient.