Increasing trend of asymptomatic hyperuricemia under treatment with urate-lowering drugs in Japan.

Objectives: To describe recent trends in the prevalence of gout and asymptomatic hyperuricemia regarding urate-lowering treatment (ULT) in Japan. Methods: A database of health insurance claims managed by the Japan Medical Data Center was used to estimate the annual prevalence of gout and asymptomatic hyperuricemia during 2010-2014. ULT was evaluated for status of the two diseases during the same period. The significance of time trends was evaluated by Cochrane-Armitage trend test. Results: The prevalence of physician-diagnosed gout in men aged 20-64 years was 1.54% (95% CI: 1.49%-1.58%) in 2010, with a slight but significant ( p  < 0.001) annual increase, up to 1.66% (95% CI: 1.62%-1.71%) in 2014. In women, gout prevalence was somewhat constant about 0.09% during 2010-2014. Among male patients with gout, 78% received ULT. The prevalence of male patients with asymptomatic hyperuricemia in the same age range, who received ULT, increased significantly from 1.77% (95% CI: 1.72%-1.81%) to 2.14% (95% CI: 2.09%-2.19%) during 2010-2014 ( p  < 0.001). Conclusion: Gout prevalence in adult men in Japan has increased significantly in recent years. The prevalence of asymptomatic hyperuricemia under ULT has also increased significantly and was higher than that of gout.