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

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, and dietary and lifestyle modifications may offer protective benefits. 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. OBS was calculated based on 16 dietary components and 4 lifestyle factors, with higher scores indicating greater antioxidant exposure. Mortality status was ascertained through linkage to the National Death Index (NDI) until December 31, 2019. Cox proportional hazards models were used to examine the association between OBS and all-cause and cardiovascular disease (CVD) mortality, adjusting for demographic, socioeconomic, and clinical covariates. Sensitivity analyses were conducted to assess robustness, including stratified analyses by smoking status and exclusion of early deaths and pre-existing CVD cases. Results During a median follow-up of 8.17 years (52,496 person-years), 970 deaths were recorded, including 327 CVD-related deaths. Higher OBS was significantly 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 CVD mortality risk (HR 0.97, 95% CI 0.95–0.99). Compared to participants in the lowest OBS quartile (Q1), those in the highest quartile (Q4) had a 47% lower risk of all-cause mortality (HR 0.53, 95% CI 0.40–0.69) and a 59% lower risk of CVD mortality (HR 0.41, 95% CI 0.25–0.67). 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 CVD cases and early deaths yielding consistent results. Conclusion This study provides strong epidemiological evidence 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 a healthy lifestyle in reducing mortality risk among this population. Future longitudinal studies and interventional trials are warranted to confirm these associations and explore the underlying biological mechanisms.