The American Diabetes Association 72nd Scientific Sessions:
In Pump Therapy, How Safe is Nighttime Suspension of Basal Insulin?
Currently, there is no insulin pump approved for use in the United States that has a low glucose suspend feature. The Medtronic Veo has this feature, and it’s approved for use in more than 50 countries, including the United Kingdom and Canada. It has a low blood glucose alarm, and if the wearer does not respond to it, the Medtronic Veo can halt basal insulin infusion. The goal is to prevent prolonged hypoglycemia—in particular nighttime hypoglycemia.
However, the US Food and Drug Administration has not approved it because of this concern: if the sensor fails and gives a false low blood glucose reading—and therefore stops basal insulin infusion—the wearer could experience ketosis.
Researchers in the diabetes community are hoping to get approval for this type of suspension system; a study presented at the American Diabetes Association 72nd Scientific Sessions looked at the safety of this suspension system in a very controlled setting.1
The poster was “Safety of Nighttime 2-Hour Suspensions of Basal Insulin in Pump-Treated Type 1 Diabetes (T1D) Even in the Absence of Low Glucose.”
There were 8 subjects in this study; all had type 1 diabetes (diabetes duration 10 ± 5 years). The subjects’ mean age was 22 ± 2 years, and their mean A1c was 7.2 ± 0.5.
How the Study Was Done
During the study, the subjects measured their blood beta hydroxybutrate (BHB) and blood glucose (BG) levels at 9pm every night, and then again at 8am the next morning (before eating breakfast).
Basal insulin injection was suspended on half the nights; it was programmed to suspend for 2 hours at random times after 11:30pm.
There were 56 suspend and 66 non-suspend nights in the research presented at the ADA meeting.
On both suspend and non-suspend nights, the BG levels were similar at 9pm, as were the BHB levels. The BG levels at 9pm on suspend nights were 148 ± 67 mg/dL; on non-suspend nights, they were 175 ± 103 mg/dL (p = 0.31 for both). The BHB levels on suspend nights were 0.06 ± 0.07 mmol/L; they were 0.07 ± 0.10 mmol/L on non-suspend nights (p = 0.91 fo rboth)
However, on suspend nights, BG levels were about 50 mg/dL higher the next morning. At 8am after suspend nights, BG levels were 201 ± 73 mg/dL, and they were 154 ± 85 mg/dL on suspend nights (p = 0.0005 for both).
BHB levels showed no statistically significant difference in the morning when comparing suspend and non-suspend nights. The levels following suspend nights were 0.14 ± 0.14 mmol/L, and on morning following non-suspend nights, they were 0.08 ± 0.10 (p = 0.07 for both).
Study Conclusion: 2-hour Basal Insulin Infusion Suspensions Could Be Safe
The study authors acknowledge that this is preliminary data, but it points to the safety of a 2-hour basal insulin infusion suspension. Even if blood glucose is elevated at the time of suspension, it seems that clinically significant ketonemia does not occur.