Abstract 13259: Differences in Glucose Readings Between Right Arm and Left Arm Using a Continuous Glucose Monitor

Abstract

Introduction: Poorly controlled diabetes increases the risk of cardiovascular disease and associated complications. Continuous glucose monitoring (CGM) devices are tools that allow clinicians and patients to gather real-time glucose levels to enhance glycemic control. CGM devices are increasingly used to optimize diabetes management, but there is no guidance on whether glucose readings differ when a CGM device is placed on the right versus the left arm. We assessed the hypothesis that a difference in time-matched glucose levels will be observed between the right and left arm. Methods: This prospective trial enrolled 46 adult volunteers to simultaneously wear CGM sensors on the right and left arms. Glucose readings were collected every 15 minutes over a 12-14 days study period. To assess if any observed inter-arm differences were a result of perfusion, participants were randomized to perform a daily 20-minute unilateral arm exercise using an assigned arm on Days 1-6, and to use the alternate arm from Day 7 to Days 12-14. Differences in glucose readings between the right and left arm were compared using the paired sample t-test. Results: A total of 41,288 time-matched glucose level pairs were collected and the mean glucose reading in the right arm was higher than that of the left arm by 3.7±10.6 mg/dL (p<0.001). Glucose readings were in hypoglycemic range (<70 mg/dL) for 22.1% of the time in the right arm and 29.8% of the time in the left arm (p<0.001), in euglycemic range (70-180 mg/dL) for 75.2% of the time in the right arm and 67.5% in the left arm (p<0.001), and in hyperglycemic range (>180 mg/dL) for 2.8% of the time in both arms (p=0.83). The difference in glucose levels between the arms was similar before and during exercise [4.0±10.2 mg/dL vs. 4.3±10.1 mg/dL, p=0.77]. Conclusions: In conclusion, glucose levels and time in hypoglycemia and euglycemia significantly differ based on arm selection during CGM device placement. This finding is unrelated to differences in perfusion induced by unilateral arm exercise. If these findings are further validated in patients with diabetes, arm selection during CGM device placement could impact therapy decisions, clinical trial design, and interpretation.