The Association Between Continuous Glucose Monitoring-derived Metrics, Including Time in Range, and Cardiovascular Autonomic Neuropathy in Outpatients With Type 2 Diabetes

Abstract BackgroundContinuous glucose monitoring (CGM)-derived metrics including time in range (TIR) are attracting attention as new indicators of glycemic control and diabetes complications beyond hemoglobin A1c. This study investigated the association between CGM-derived TIR, hyperglycemia, hypoglycemia metrics, and cardiovascular autonomic neuropathy (CAN) in patients with type 2 diabetes.MethodsA total of 284 patients with type 2 diabetes who underwent CGM for three days and autonomic function tests within three months based on outpatient data were recruited. The definition of CGM-derived metrics was subject to the most recent international consensus. CAN was defined as an abnormal case in two or more parasympathetic and the severity of CAN was estimated as the sum of the scores of the five cardiovascular autonomic function tests.ResultsMultiple logistic regression analysis revealed that the odds ratio of definite CAN was 0.876 [95% confidence interval (CI): 0.79–0.98] per 10% increase in the TIR of 70 to 180 mg/dL, after adjusting for age, sex, diabetes duration, any medications, and glycemic variability. A 10% increase in TIR was significantly inversely associated with the presence of advanced CAN (OR: 0.89, 95% CI: 0.81–0.98). In addition, there was a strong inverse association between a 10% increase in the TIR and the total CAN score (p for trend = 0.001). Among the metrics of hyperglycemia, a time above range (TAR) of greater than 180 mg/dL was also independently correlated with the presence of definite CAN (OR: 1.013, 95% CI: 1.00–1.02) and advanced CAN (OR: 1.01, 95% CI: 1.00–1.02).ConclusionsA TIR value of 70 to 180 mg/dL and a TAR value of greater than 180 mg/dL were significantly associated with cardiovascular autonomic neuropathy in outpatients with type 2 diabetes.