Factors Associated With Nocturnal Hypoglycemia After Exercise in the Type 1 Diabetes and Exercise Initiative (T1DEXI) Study.

Abstract

To identify modifiable factors associated with postexercise nocturnal hypoglycemia in the Type 1 Diabetes and Exercise Initiative (T1DEXI) study. In this real-world prospective cohort study, overnight continuous glucose monitoring data following exercise days versus sedentary days were assessed in adults with type 1 diabetes. Nocturnal hypoglycemia was defined as a continuous glucose monitoring level of 54-69 mg/dL (level 1) or <54 mg/dL (level 2) for ≥15 min between midnight and 6:00 a.m. Among 496 adults across 12,340 nights, exercise days were associated with more frequent level 1 nocturnal hypoglycemia relative to sedentary days (15.6% vs. 13.1%, P = 0.001). Factors associated with reduced risk included lower preexercise time below range, higher preexercise and bedtime glucose, absence of hypoglycemia during or within 4 h after exercise, and hybrid closed-loop delivery. Time below range ≥4% in the 24 h preceding exercise was associated with substantially higher nocturnal hypoglycemia risk relative to <4% for level 1 (22.9% vs. 11.7%) and level 2 (10.2% vs. 3.3%) (both P < 0.001). Hybrid closed-loop users experienced approximately half the rate of nocturnal hypoglycemia compared with participants using standard pumps or multiple daily injections (level 1: 9.7% vs. 20.3% vs. 17.3%, respectively; level 2: 3.2% vs. 7.2% vs. 5.8%, respectively) (both P < 0.001). In the T1DEXI study, exercise was associated with increased nocturnal hypoglycemia risk in adults with type 1 diabetes. Targeting modifiable factors may reduce risk and address a critical barrier to safe physical activity in type 1 diabetes.