Safety of Nighttime 2-Hour Suspension of Basal Insulin in Pump-Treated Type 1 Diabetes Even in the Absence of Low Glucose

Abstract

OBJECTIVEAn integrated sensor-augmented pump system has been introduced that interrupts basal insulin infusion for 2 h if patients fail to respond to low-glucose alarms. It has been suggested that such interruptions of basal insulin due to falsely low glucose levels detected by sensor could lead to diabetic ketoacidosis. We hypothesized that random suspension of basal insulin for 2 h in the overnight period would not lead to clinically important increases in blood β-hydroxybutyrate levels despite widely varying glucose values prior to the suspension.RESEARCH DESIGN AND METHODSSubjects measured blood glucose and blood β-hydroxybutyrate levels using a meter each night at 9:00 p.m., then fasted until the next morning. On control nights, the usual basal rates were continued; on experimental nights, the basal insulin infusion was reprogrammed for a 2-h zero basal rate at random times after 11:30 p.m.RESULTSIn 17 type 1 diabetic subjects (mean age 24 ± 9 years, diabetes duration 14 ± 11 years, A1C level 7.3 ± 0.5% [56 mmol/mol]), blood glucose and blood β-hydroxybutyrate levels were similar at 9:00 p.m. on suspend nights (144 ± 63 mg/dL and 0.09 ± 0.07 mmol/L) and nonsuspend nights (151 ± 65 mg/dL and 0.08 ± 0.06 mmol/L) (P = 0.39 and P = 0.47, respectively). Fasting morning blood glucose levels increased after suspend nights compared with nonsuspend nights (191 ± 68 vs. 141 ± 75 mg/dL, P < 0.0001), and the frequency of fasting hypoglycemia decreased the morning following suspend nights (P < 0.0001). Morning blood β-hydroxybutyrate levels were slightly higher after suspension (0.13 ± 0.14 vs. 0.09 ± 0.11 mmol/L, P = 0.053), but the difference was not clinically important.CONCLUSIONSSystems that suspend basal insulin for 2 h are safe and do not lead to clinically significant ketonemia even if the blood glucose level is elevated at the time of the suspension.

The Artificial Pancreas: Are We There Yet?

“…Their findings demonstrated that “routine measurement of blood or urine ketones during use of an automated pump suspension system using continuous glucose monitoring, whether threshold based or predictive, is not necessary” (7). These findings confirm and extend those of Sherr et al (8) that were also reported in a recent issue of Diabetes Care .…”

Accuracy of a New Patch Pump Based on a Microelectromechanical System (MEMS) Compared to Other Commercially Available Insulin Pumps

“…18 Previous studies on cessation of rapid delivery of insulin analogues showed that glycemic changes began to occur 1 hour after cessation and were more consistent after 2 or 3 hours. [19][20][21][22] In the case of a 2-hour overnight insulin cessation, glucose levels at the end of the interruption period rose by 16 ± 34 mg/dL at 2 hours and by 63 ± 57 mg/ dL at 4 hours. 19 Another study with a 30-minute interruption reported that the rate of the rise in glucose was 1 mg/dL for each minute the insulin infusion was interrupted, but that the maximum increase was observed 3 hours afterward.…”

“…[19][20][21][22] In the case of a 2-hour overnight insulin cessation, glucose levels at the end of the interruption period rose by 16 ± 34 mg/dL at 2 hours and by 63 ± 57 mg/ dL at 4 hours. 19 Another study with a 30-minute interruption reported that the rate of the rise in glucose was 1 mg/dL for each minute the insulin infusion was interrupted, but that the maximum increase was observed 3 hours afterward. 21 In a study of prolonged insulin interruption, β hydroxybutyrate increased in parallel with blood glucose, reaching 1 mmol/L after 3 hours.…”

ISPAD Clinical Practice Consensus Guidelines 2018: Diabetes technologies

“…To address concerns of what could happen if insulin suspension occurred based off the readings of an inaccurate CGM, random 2‐hour preprogrammed insulin suspensions were conducted overnight in a cohort of participants in their home setting as long as pre‐bed blood glucose was <300 mg/dL (16.7 mmol/L) and blood beta‐hydroxybutyrate (BHB) levels were <0.5 mmol/L . A total of 118 suspend nights were compared to 131 non‐suspend nights and showed the morning after suspensions, blood glucose was ~50 mg/dL (2.7 mmol/L) higher but there was no clinically meaningful difference in BHB levels …”