Association between time in range and incident early diabetic kidney disease in patients with type 2 diabetes: a retrospective cohort study

BACKGROUND: Diabetic kidney disease (DKD) is a leading cause of end-stage renal disease in type 2 diabetes mellitus (T2DM). Time in range (TIR), a continuous glucose monitoring-derived metric, has emerged as an important glycemic control indicator, but evidence linking TIR to incident early DKD in T2DM remains limited. METHODS: This retrospective cohort study included 498 Chinese T2DM patients with preserved kidney function at baseline who underwent continuous glucose monitoring between January 2020 and December 2022, with follow-up until December 2024. TIR and other glycemic metrics were assessed at baseline. The primary outcome was incident early DKD. Cox proportional hazards models evaluated associations between TIR and early DKD risk, with comprehensive adjustment for demographics, clinical characteristics, and medications. Subgroup and sensitivity analyses were performed. RESULTS: During a median 24-month follow-up, 62 (12.4%) patients developed early DKD. After full adjustment, TIR ≥ 70% was associated with lower early DKD risk versus TIR < 70% (HR = 0.54, 95%CI 0.30-0.96, p = 0.048). A significant dose-response relationship was observed across TIR quartiles (P for trend = 0.008), with each 10% TIR increase associated with a 16% risk reduction (HR = 0.84, 95%CI 0.73-0.98, p = 0.022). The protective association was more pronounced in patients not using sodium-glucose cotransporter 2 inhibitors (P for interaction = 0.036). Results remained consistent across sensitivity analyses. CONCLUSIONS: Higher TIR is significantly associated with reduced risk of incident early DKD in T2DM patients with preserved kidney function, exhibiting a clear dose-response pattern. TIR may serve as a valuable complementary metric for assessing renal complication risk.