Association Between Short-Term Glycemic Variability Measured by Continuous Glucose Monitoring and Early Diabetic Kidney Disease in Type 2 Diabetes
Background The role of short‑term glycemic variability (GV) in early diabetic kidney disease (DKD) among patients with type 2 diabetes (T2D) remains controversial. This study aims to investigate the independent association between continuous glucose monitoring (CGM)-derived GV indices and early DKD in T2D patients. Methods This cross-sectional study included 315 patients with T2D. Early DKD was identified as persistent microalbuminuria (urine albumin-to-creatinine ratio 30–300 mg/g) with preserved renal function (eGFR≥60 mL/min/1.73 m2). GV metrics, including mean amplitude of glycemic excursions (MAGE) and glucose standard deviation (SDBG), were derived from CGM data. Multivariate logistic regression and generalized additive models (GAMs) were used to assess associations, with subgroup analyses and interaction tests. Results Participants with early DKD had significantly higher MAGE and SDBG (both P<0.001). After full adjustment for HbA1c, medication use, and other covariates, both MAGE (OR =1.58, 95% CI: 1.31–1.89, P<0.001) and SDBG (OR =2.14, 95% CI: 1.39–3.30, P = 0.001) were independently associated with early DKD. Compared with the lowest tertile, the highest tertiles of MAGE and SDBG were associated with a 5.78-fold (95% CI: 2.83–11.81) and 3.56-fold (95% CI: 1.77–7.18) higher risk, respectively (all P< 0.001). BMI was a significant effect modifier of the MAGE-DKD association (P for interaction = 0.014), which was present only in overweight/obese individuals. GAM analysis demonstrated a linear positive relationship for MAGE and a non-linear U-shaped association for SDBG. Conclusion CGM-derived short-term GV indices MAGE and SDBG are independently associated with early DKD in T2D patients, with distinct dose-response patterns: MAGE shows a linear positive relationship, whereas SDBG exhibits a U-shaped association. Moreover, the MAGE–DKD association is confined to overweight individuals. Prospective studies are needed to establish causality and to verify whether personalized targeting of short‑term GV might be associated with lower DKD risk.