Background: To date, there is no appropriate scheme to lower Serum Uric Acid (SUA) in patients with SUA between 7.0-9.0 mg/dL without symptoms and comorbidities. We wondered whether Small Molecule Water (SMW) lower SUA in these patients.

Methods: This multicenter, randomized, double-blind, placebo-controlled trial was conducted at six tertiary hospitals in China. Participants aged at least 18 years with asymptomatic hyperuricemia who had no comorbidities were screened. Patients were randomly assigned (1:1) to either SMW (1600 ml/day, intervention) or placebo (raw water, 1600ml/day, control), simultaneously recommending to follow a conventional low-purine (i.e., plant-dominant low-protein) diet. The primary outcome was the mean change of SUA from baseline to 12 weeks.

Results: 232 participants were enrolled from 6 tertiary hospitals. Mean SUA decreased by 0.71 mg/dL (95% CI 0.37-1.03 mg/dL) from baseline to 12 weeks in the intervention group and by 0.36 mg/dL (95% CI 0.26-0.45 mg/dL) in the control group, with a group difference of 0.35 mg/dL (95% CI 0.25-0.35 mg/dL; p<0∙0001). At 12 weeks, 44 (35.3%) of 116 patients in the intervention group and 24 (20.7%) of 116 patients in the control group had an SUA of less than 7.0 mg/dl, with a relative risk of 1.71 (95% CI 1.33-2.14). Also, body mass index, total cholesterol, and low-density lipoprotein cholesterol decreased, but high-density lipoprotein cholesterol increased in the intervention group.

Conclusion: SMW may short-termly lower SUA and improve body metabolism in adult patients with asymptomatic hyperuricemia on a conventional low-purine diet.