Urinary markers of nucleic acid oxidation and long-term mortality of newly diagnosed type 2 diabetic patients.

Abstract

We analyzed data from a cohort of 1,381 newly diagnosed type 2 diabetic patients to test the hypothesis that urinary markers of nucleic acid oxidation are independent predictors of mortality. We examined the relationship between urinary excretion of markers of DNA oxidation (8-oxo-7,8-dihydro-2'-deoxyguanosine [8-oxodG]) and RNA oxidation (8-oxo-7,8-dihydroguanosine [8-oxoGuo]) and long-term mortality using Cox proportional hazards regression. After multivariate adjustment, the hazard ratios for all-cause and diabetes-related mortality of patients with 8-oxoGuo levels in the highest quartile compared with those in the lowest quartile were 1.44 (1.12-1.85) and 1.54 (1.13-2.10), respectively. Conversely, no significant associations between 8-oxodG and mortality were found in the adjusted analyses. Urinary excretion of the RNA oxidation marker 8-oxoGuo measured shortly after diagnosis of type 2 diabetes predicts long-term mortality independently of conventional risk factors. This finding suggests that 8-oxoGuo could serve as a new clinical biomarker in diabetes.