Purpose: Higher baseline serum urate or higher initial urate-lowering medication dose increased risk of gout flares during urate-lowering therapy (ULT) initiation. The decrease in serum urate may play a crucial role in this process. Therefore, we aim to explore the relationship between decrease in serum urate and the risk of gout flares during ULT initiation.
Patients and methods: A 12-week prospective cohort study of Chinese male gout patients was conducted at Shandong Provincial Clinical Research Center for Immune Diseases and Gout in China. Patients were grouped by baseline serum urate (7-7.9 mg/dL, 8-8.9 mg/dL and ≥9 mg/dL). All patients received febuxostat 20 mg daily during weeks 0-4, then escalated to 40mg during weeks 4-12 if serum urate >6mg/dL. The main outcomes were the number of gout flares and the decrease in serum urate. Poisson regression was performed.
Results: A total of 282 participants were enrolled, of whom 260 completed (84, 87 and 89 in each group) from March 2021 to December 2021. A 44.2% of all participants experienced at least one gout flare. In the multivariate Poisson regression 1, Δ serum urate 0-12 weeks (IRR 1.184, 95% CI, 1.062-1.320; P=0.002), the number of gout flares before treatment 1 year (1.017, 1.010-1.024; P<0.001) and tophus (1.580, 1.023-2.440; P=0.039) were independently associated with the number of gout flares. While in the multivariate Poisson regression 2, baseline serum urate (1.256, 1.050-1.503; P=0.013) and the number of gout flares before treatment 1 year (1.014, 1.007-1.022; P<0.001) were independently associated with the number of gout flares, Δ serum urate 0-12 weeks (1.055, 0.923-1.207; P=0.433) was no longer a risk factor.
Conclusion: ULT-induced gout flares depend on the degree of decrease in serum urate, which is affected by baseline serum urate. Higher baseline serum urate and greater decrease in serum urate lead to higher risk of gout flares.
Keywords: baseline serum urate; decrease in serum urate; febuxostat; gout flares.
© 2023 Pang et al.