Continuous Glucose Monitoring for Evaluation of Glycemic Excursions after Gastric Bypass

Table 2

Results from continuous glucose monitoring and mixed meal tolerance testing on post-gastric bypass subjects with documented episodes of neuroglycopenia on medical treatment (TX-SX) or without any symptoms of hypoglycemia (ASX).

	Gastric bypass with neuroglycopenia; (TX-SX)	Gastric bypass asymptomatic; (ASX)	𝑃 value
CGM
Average interstitial glucose (mg/dL)	104±3	101±3	𝑃=1.00
Average number of daily excursions <70 mg/dL	1.45±0.42	0.78±0.44	𝑃=.10
Minutes/day glucose <70 mg/dL	63±23	34±22	𝑃=.28
Minutes/day glucose <60 mg/dL	30±14	18±12	𝑃=.45
Average minimum glucose (mg/dL)	58±5	64±7	𝑃=.46
Average maximum glucose (mg/dL)	213±13	167±13	𝑃=.03
Minutes/day glucose >180 mg/dL	11±3	9±6	𝑃=.59
Total abnormal glucose excursions (hypoglycemic <70 mg/dL, plus hyperglycemic >180 mg/dL)	8.5±2.1	3.8±2.3	𝑃=.05
MMTT
Fasting blood glucose (mg/dL)	73±1	75±2	𝑃=.40
Glucose area under curve (0–120 mins) (mg/dL/min)	3399±695	2285±782	𝑃=.50
Glucose at time 120 mins (mg/dL)	71±1	77±3	𝑃=.05
Fasting insulin (μU/mL)	3.6±0.8	3.2±0.9	𝑃=.70
Insulin at time 30 mins (μU/mL)	129±27	88±20	𝑃=.30
Insulin at time 60 mins (μU/mL)	25±5	15±4	𝑃=.15
Sensitivity*
CGM	9/10 (90%)
MMTT	3/9 (33%)
Specificity**
CGM	3/6 (50%)
MMTT	2/5 (40%)

Data presented as mean ± standard error. CGM: continuous glucose monitoring; MMTT: mixed meal tolerance testing.
* Sensitivity = number of true positives/(number of true positives + number of false negatives).
** Specificity = number of true negatives/(number of true negatives + number of false positives). True positive is defined as a numerical value of hypoglycemia (glucose <70 mg/dL) during a test in a subject with the prior clinical occurrence of neuroglycopenia (TX-SX group). A false positive is defined as a numerical value of hypoglycemia during a test in a subject without the presence or history of symptoms.