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

  1. Stuart A Weinzimer, MD1
  1. 1Department of Pediatrics, Yale University School of Medicine, New Haven, CT
  1. Address correspondence to: Jennifer Sherr, jennifer.sherr{at}


Objective An integrated sensor-augmented pump system has been introduced that interrupts basal insulin infusion for 2-hrs if patients fail to respond to low glucose alarms. It has been suggested that such interruptions of basal insulin due to falsely low sensor glucose levels could lead to diabetic ketoacidosis. We hypothesized that random suspension of basal insulin for 2-hrs in the overnight period would not lead to clinically important increases in blood β-hydroxybutyrate (BHB) levels despite widely varying glucose values prior to the suspension.

Research Design and Methods Subjects measured meter blood glucose (BG) and BHB levels each night at 9PM and fasting the next morning. On control nights, usual basal rates were continued; on experimental nights, the basal insulin infusion was re-programmed for a 2-hr zero basal rate at random times after 11:30PM.

Results In seventeen type 1 diabetes subjects (age 24±9yr, duration 14±11yr, A1c 7.3±0.5 [56mmol/mol]) BG and BHB levels were similar at 9PM on suspend (144±63mg/dL and 0.09±0.07mmol/L) and non-suspend (151±65mg/dL and 0.08±0.06mmol/L) nights (p=0.39 and p=0.47, respectively). Fasting morning BG increased following suspend nights compared to non-suspend nights (191±68mg/dL vs. 141±75mg/dL, p<0.0001) and the frequency of fasting hypoglycemia decreased the morning following suspend nights (p<0.0001). Morning BHB levels were slightly higher after suspension (0.13±0.14mmol/L vs. 0.09±0.11mmol/L, p=0.053) but the difference was not clinically important.

Conclusions Systems that suspend basal insulin for 2-hrs are safe and do not lead to clinically significant ketonemia even if BG is elevated at the time of the suspension.

  • Received July 8, 2013.
  • Accepted October 24, 2013.

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  1. Diabetes Care
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