Association of Time in Tight Range with Microvascular Complications in Japanese Patients with Type 2 Diabetes Mellitus: A Multicenter Cross-Sectional Study

Background: To determine the correlation between time in tight range (TITR; 70–140 mg/dL) and prevalence of microvascular complications in patients with type 2 diabetes mellitus (T2DM). Methods: Data of 999 patients with T2DM and negative history of cardiovascular disease were analyzed. TITR was assessed using data from a continuous glucose monitoring (CGM) system. Participants were stratified into quartiles based on TITR (Q1: ≤42.6%, Q2: >42.6 to ≤61.2%, Q3: >61.2 to ≤73.4%, Q4: >73.4%). The correlation of TITR/microvascular complications was assessed using multivariate logistic regression analysis after adjustment for potential confounders. Results: The mean TITR was 56.8 ± 22.4%, and 51.2% of participants had at least one microvascular complication. The adjusted odds ratios for any microvascular complication across increasing TITR quartiles were 1.00 (Q1 as the reference group), 0.39 (Q2; 95% confidence interval [CI]: 0.25–0.62), 0.45 (Q3; 95% CI: 0.28–0.70), and 0.30 (Q4; 95% CI: 0.19–0.47). This indicated that the prevalence of diabetic microvasculopathies was lower in higher TITR quartiles. Similar inverse trends were observed for retinopathy, nephropathy, and peripheral neuropathy. Each 10% increase in TITR was associated with a reduced risk of each type of diabetic microvasculopathy. Receiver operating characteristic curve analysis identified 54.3% as the optimal TITR cutoff value for the identification of microvascular complications. Conclusions: Higher TITR was significantly associated with lower prevalence of microvascular complications in patients with T2DM. CGM-derived TITR is a potentially useful clinical metric for optimizing glycemic management and reducing the risk of microvascular complications. Trial Registration Number: UMIN000032325.