Indicator of RNA oxidation in urine for the prediction of mortality in patients with type 2 diabetes and microalbuminuria: A post-hoc analysis of the Steno-2 trial
Laura Kofoed Kjaer, Jens Oellgaard, Trine Henriksen, Peter Gaede, Oluf Pedersen, Henrik Enghusen Poulsen, Laura Kofoed Kjaer, Jens Oellgaard, Trine Henriksen, Peter Gaede, Oluf Pedersen, Henrik Enghusen Poulsen
Abstract
Objective: The RNA oxidation product, 8-oxo-7,8-dihydroguanosine (8-oxoGuo), has been associated with mortality in patients with type 2 diabetes (T2D). However, the identification and the potential effect of approved treatments decreasing urine 8-oxoGuo level remain unraveled. In the Steno-2 study intensified multifactorial treatment compared with conventional multifactorial treatment reduced mortality in T2D patients with microalbuminuria by 45%. We assessed association between 8-oxoGuo at advanced baseline and total mortality with up to 19.9 years follow-up and from end of intervention to end of follow-up up to (up to 13.9 years).
Materials and methods: In 1993, 160 T2D patients with microalbuminuria were included in the Steno-2 trial. Urine samples from baseline were not available, but samples were available from 155 patients (97%) in 1995 (advanced baseline) and from 125 patients (96%) in 2001 (end of intervention). Hazard ratios (HR) for log2-transformed 8-oxoGuo and dichotomized (cut-off at median; low vs. high RNA oxidation) were estimated using Cox regressions.
Results: During follow-up of 19.9 years after advanced baseline, 89 died and no association between 8-oxoGuo and mortality was found (p = 0.40). From the end of 7.8 years of intervention and during remaining 13.9 years of observation, 61 died and doubling the urine 8-oxoGuo level was associated with mortality with a HR 3.08 (95% CI [1.86 -5.12]; p < 0.001) after multiple adjustments. Patients with low 8-oxoGuo in the intensified-treatment had the lowest risk of dying compared with high 8-oxoGuo in the conventional-treatment both from advanced baseline onwards, adjusted HR 0.40 (95% CI [0.21 -0.75]; p = 0.004), and from end of intervention onwards, adjusted HR 0.28 (95% CI [0.13 -0.61]; p = 0.001).
Conclusions: In T2D patients with microalbuminuria, high levels of urine 8-oxoGuo after 7.8 years of multifactorial intervention was associated with higher mortality during 13.9 years of post-trial follow-up. Patients with low 8-oxoGuo in the intensified treatment group had the lowest risk of dying.
Keywords: 8-dihydro-2-deoxyguanosine; 8-dihydroguanosine; 8-oxo-7; Clinical markers; Diabetic complications; Oxidative stress; Type 2 diabetes.
Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.
Source: PubMed