Time in Range as a Marker of Concurrent Glycemic and Lipid Improvement in Adults with Type 2 Diabetes: A Real-World Retrospective Pre–Post Study

This study aims to evaluate whether continuous glucose monitoring (CGM)-derived time in range (TIR) attainment is associated with concurrent improvements in glycemic control and lipid profiles among adults with type 2 diabetes mellitus (T2DM). In this retrospective, single-arm pre–post study, 542 adults with T2DM who underwent intermittently scanned CGM for 12 weeks were analyzed. Glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), total cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were compared before and after CGM use. Participants were stratified by TIR into low (<50%), intermediate (50–70%), and target (>70%) groups. Overall, HbA1c decreased from 8.12% to 7.49% and FPG from 153.35 to 136.70 mg/dL (both p < 0.001). Significant improvements were also observed in total cholesterol, triglycerides, HDL-C, and LDL-C. Glycemic improvement occurred across all TIR strata; however, significant improvements in all lipid parameters were observed only in participants achieving TIR >70%. In this group, total cholesterol decreased by 4.23 mg/dL, triglycerides by 11.12 mg/dL, and LDL-C by 4.48 mg/dL, and HDL-C increased by 1.34 mg/dL. These findings suggest that achieving the consensus TIR target of >70% may be associated with broader cardiometabolic benefits beyond glycemic improvement alone. TIR may therefore serve as a clinically useful complementary target to HbA1c in routine diabetes management.