Glucose Patterns in Very Old Adults: A Pilot Study in a Community-Based Population

Abstract

Context: Continuous glucose monitoring (CGM) provides nuanced information on glucose patterns, but data in very old adults are scarce. Objective: To evaluate CGM patterns in very old adults. Design: Pilot study. Setting: Participants recruited from one center during visit 7 (2019) of the community-based Atherosclerosis Risk in Communities (ARIC) Study. Participants: We enrolled 27 adults (8 with type 2 diabetes and 19 without diabetes) who wore a CGM sensor (Abbott Libre Pro) for up to 14 days. Clinical and laboratory measures, including hemoglobin A1c (HbA1c), were obtained. Main Outcomes: Mean CGM glucose, standard deviation (SD), coefficient of variation (CV), time-in-range (TIR) 70-180 mg/dL, and hypoglycemia. Results: Mean age was 81 (range 77-91 years) and mean CGM wear time was 13.2 days. In persons without diabetes, there was a wide range of CGM parameters: range of mean glucose, 83.7-124.5 mg/dL, SD 12.2-27.3 mg/dL, CV 14.0%-26.7%, and TIR 71.1%-99.5%. In persons with diabetes, the range of mean CGM glucose was 105.5-223.0 mg/dL, SD, 22.3-86.6 mg/dL, CV 18.2%-38.8%, TIR 38.7%-98.3%. The Pearson's correlation of mean glucose with HbA1c was high overall (0.90); but, for some participants with similar HbA1c, glucose patterns differed substantially. There was a high prevalence of hypoglycemia (glucose <70 or <54 mg/dL) in both persons with and without diabetes. Conclusions: There was high feasibility and acceptability of CGM in very old adults. Low readings on CGM are common, even in nondiabetic older adults; the clinical relevance of these low values is unclear. CGM may provide complementary information to HbA1c in some older adults.

Keywords: Biomarkers; Continuous glucose monitoring; Elderly; Glycemic variability; HbA1c; The ARIC study; Very old adults.

FIG. 1.

Daily glucose patterns of pilot study participants without diabetes.

FIG. 1.

Daily glucose patterns of pilot study participants without diabetes.

FIG. 2.

Daily glucose patterns of pilot study participants with diagnosed type 2 diabetes.

FIG. 3.

Scatterplots of mean glucose with HbA1c, fasting glucose, fructosamine, glycated albumin, and 1,5-AG. Lines are from linear regression models in the overall study population (solid black line) and in persons with diabetes (dotted line) and without diabetes (solid gray line). 1,5-AG, 1,5-anhydroglucitol; HbA1c, hemoglobin A1c.