Table 4.

Summary table of studies of CGM in PBH.

Study	Population	Investigation	Definition of hypoglycaemia	Outcome
Rett, 2013 (56)	Symptomatic RYGB, n = 27	Dexcom seven+ CGM over 7 days	<70 mg/dL (<3.9 mmol/L)	Hypoglycaemia detected in 93%. Raised GV as measured by MAG.
Nielsen, 2015 (57)	Symptomatic RYGB, n = 12 Asymptomatic RYGB, n = 12	Not specified CGM over 6 days Both sets of people subjected to 5-h MMT, low-carbohydrate diet for 1 day, ordinary diet for rest of monitoring period	Not specified	CGM glucose levels overestimate plasma glucose during an MMT by 1.0 mmol/L. Raised GV as measured by MAGE during low carbohydrate diet lower than during ordinary diet.
Ritz, 2016 (58)	Symptomatic non-specified bariatric surgery, n = 142 Asymptomatic non-specified bariatric surgery, n = 25	Not specified CGM system	<60 mg/dL (<3.33 mmol/L) Cohort divided into those with hypos and those without	Hypo people had more time in hypo <60 mg/dL and GV. No difference in symptoms of hypos between people with hypos and those without. Sigstad dumping syndrome score higher in hypo people.
Halperin, 2011 (59)	Asymptomatic RYGB, n = 6 Symptomatic RYGB, n = 10	Medtronic Minimed iPro CGM for 72–120 h All people also subjected to MMT (Ensure, 9 g protein, 40 g carbohydrates, 6 g fat, 240 mL; Abbott)	<70 mg/dL (<3.9 mmol/L)	9/10 symptomatic people had hypos on CGM and 3/9 on MMT. 3/6 asymptomatic people had hypos on CGM and 3/5 on MMT. Sensitivity of CGM for clinically significant hypo was 90% and specificity 50% (33%, 40% for MMT).
Kefurt, 2015 (46)	Symptoms not stated RYGB, n = 51	Medtronic iPro-2 CGM over 5 days	<55 mg/dL (<3.1 mmol/L)	75% had hypo episodes with mean duration 71 min.
Capristo, 2018 (29)	Randomly selected RYGB, n = 25 Randomly selected SG, n = 25 (out of cohort of 120 people assigned 1:1 to RYGB vs SG)	Medtronic Enlite for up to 5 days	<55 mg/dL (<3.1 mmol/L)	No difference in average daily glycaemic values ≤3.1 mmol/L nor daily average number of hypo episodes between RYGB vs SG.
Lobato, 2020 (60)	Symptomatic RYGB, n = 13	Abbott FreeStyle Libre for 14 days, first 48 h excluded	<70 mg/dL (<3.9 mmol/L) with concurrent hypoglycaemic symptoms or <54 mg/dL (<3.0 mmol/L)	Significant hypoglycemia (time in range <54 mg/dL/<3.0 mmol/L ≥1%) in 8/13.
Ilesanmi, 2021 (13)	Asymptomatic RYGB, n = 10	Dexcom G4 or G6 CGM for up to 10 days Assessed before surgery, at 1 month, 1 year and 2 years after surgery MMT with Ensure Compact (13 g protein, 11.6 g fat, 36 g carbohydrates, 330 kcal, 137.5 mL; Abbott) before surgery, at 1 month, 1 year	<3.0 and <3.9 mmol/L	Significant hypoglycaemia (time in range <3.0 mmol/L >1%) in 5/10. GV similar between baseline pre-surgery and at 1 month, but increased at 1 year and 2 years after surgery. Prevalence of asymptomatic hypo in Roux-en-Y gastric bypass was 50%.

CGM, continuous glucose monitoring; GV, glycaemic variation; (L)AGB, (laparoscopic) adjustable gastric banding; MAG, mean absolute glucose; MAGE, mean absolute glucose excursion; MMT, mixed meal test; RYGB, Roux-en-Y gastric bypass; SG, sleeve gastrectomy.