Association between the oxidative balance score and all-cause and cardiovascular mortality in patients with diabetes and prediabetes

Few studies have examined the link between systemic oxidative stress and mortality risk in diabetes and prediabetes patients. The Oxidative Balance Score (OBS) is a novel measure of systemic oxidative stress, with higher scores indicating greater antioxidant exposure. This study investigates the relationship between OBS and all-cause and cardiovascular mortality in these patients. This study analyzed 10,591 diabetes and prediabetes patients from the 1999-2018 National Health and Nutrition Examination Survey (NHANES). The endpoints were all-cause and cardiovascular mortality, determined from the National Death Index (NDI). OBS was calculated using 20 dietary and lifestyle factors. Kaplan-Meier survival analysis, multivariable Cox regression models, restricted cubic splines (RCS), and subgroup analyses were used to assess the relationship between OBS and mortality risks. Over an average follow-up of 99.8 months, 2900 (26.4 %) participants died, including 765 (8.9 %) from cardiovascular diseases. Kaplan-Meier analysis showed the lowest all-cause and cardiovascular mortality in the highest OBS quartile (Q4) and the highest mortality in the lowest quartile (Q1) (p < 0.001). In the fully adjusted model, multivariable Cox regression revealed that each unit increase in OBS was linked to a 1.8 % decrease in all-cause mortality risk (HR 0.982, 95 % CI 0.976-0.987, p < 0.0001) and a 4 % decrease in cardiovascular mortality risk (HR 0.960, 95 % CI 0.949-0.970, p < 0.0001). Compared to Q1, those in Q4 had significantly lower all-cause mortality (HR 0.719, 95 % CI 0.643-0.804, p < 0.0001, p for trend <0.0001) and cardiovascular mortality (HR 0.567, 95 % CI 0.455-0.705, p < 0.0001, p for trend <0.0001). These findings were consistent across subgroups. RCS curves showed a negative correlation between OBS and both mortality types. Higher OBS is linked to reduced all-cause and cardiovascular mortality in diabetes and prediabetes patients.