Short Leukocyte Telomere Length Predicts Albuminuria Progression in Individuals With Type 2 Diabetes

Introduction: Telomere length, a marker for biological aging, is implicated with diabetic kidney disease (DKD); however, the association between telomere length and albuminuria progression among Asian patients with type 2 diabetes (T2D) is not well understood. Here, we aim to study whether leukocyte telomere length (LTL) may independently predict albuminuria progression in patients with T2D with preserved renal filtration function (estimated GFR >60 ml/min per 1.73 m(2) and urine albumin-to-creatinine ratio [uACR] <300 mg/g). Methods: The baseline LTL was measured by real-time polymerase chain reaction in the SMART2D cohort (n = 691) with a median follow-up of 3 years. Albuminuria progression was defined as a change in albuminuria category to a higher category and at least 30% increase in uACR from baseline in 3 years. Results: Progressors (n = 123) had significantly shorter median LTL compared with nonprogressors (n = 568) (0.58 [0.38-0.79] vs. 0.62 [0.45-0.88], P = 0.039). Compared with subjects with longer LTL (fourth quartile), subjects with shorter LTL (first quartile) had 1.93-fold (1.04-3.60, P = 0.038) increased risk for albuminuria progression after adjustment for traditional risk factors. The association of LTL with micro-albuminuria to macroalbuminuria progression was stronger than its association with normoalbuminuria to microalbuminuria (odds ratio [OR]: 1.54; 95% confidence interval [CI]: 1.02-2.32; P = 0.042 vs. OR: 1.13; 95% CI: 0.91-1.40; P = 0.263 per 1-SD decrement in natural log-transformed LTL). Conclusion: Therefore, our results demonstrated that in patients with T2D with preserved renal filtration function, LTL predicts albuminuria progression beyond traditional risk factors, suggesting LTL may be novel biomarker for DKD progression.