Association of oxidative balance score and all-cause and cardiovascular mortality in patients with hyperuricemia and gout: NHANES 1999-2018

Background Hyperuricemia and gout are metabolic disorders associated with an increased risk of all-cause and cardiovascular mortality. Oxidative stress plays a crucial role in their pathogenesis. The Oxidative Balance Score (OBS), an integrative measure of dietary and lifestyle oxidative balance, has been linked to chronic disease outcomes. However, its association with mortality risk in individuals with hyperuricemia and gout remains unclear. This study aims to investigate the relationship between OBS and all-cause and cardiovascular mortality in patients with hyperuricemia and gout, using data from the National Health and Nutrition Examination Survey (NHANES) 1999–2018. Methods A total of 6,178 non-pregnant adults (aged 20–79 years) with hyperuricemia or gout were included from NHANES 1999-2018. Mortality status was ascertained through linkage to the National Death Index (NDI) until December 31, 2019. Multivariable cox proportional hazards models were used to examine the association between OBS and all-cause and cardiovascular mortality risk. Stratified analyses, interaction analyses, sensitivity analyses and restricted cubic spline (RCS) regression were conducted to assess robustness. Results During a median follow-up of 8.17 years (52,496 person-years), 970 deaths were recorded, including 327 cardiovascular disease-related deaths. Higher OBS was associated with lower mortality risk. In the fully adjusted model, each unit increase in OBS was linked to a 2% reduction in all-cause mortality risk (HR 0.98, 95% CI 0.96–0.99) and a 3% reduction in cardiovascular mortality risk (HR 0.97, 95% CI 0.95–0.99). Kaplan-Meier survival analysis and restricted cubic splines confirmed an inverse, score-dependent relationship between OBS and mortality ( p -overall < 0.001). Stratified analyses showed that the inverse association between OBS and all-cause mortality was weaker in current smokers, suggesting potential interactions between smoking and oxidative stress pathways ( p -interaction = 0.03). Sensitivity analyses further supported the robustness of the findings, with the exclusion of pre-existing cardiovascular disease cases and early deaths yielding consistent results. Conclusion This study indicates that a higher OBS is associated with lower all-cause and cardiovascular mortality risk in individuals with hyperuricemia and gout. These findings highlight the potential benefits of an antioxidant-rich diet and lifestyle in strategies aimed at preventing and managing hyperuricemia and gout.