In this exploratory monocentric study performed at the Caen University Hospital in France,
adult T2D patients consecutively enrolled for metabolic surgery will be prospectively
included for continuous glucose monitoring (CGM) recordings during the month preceding
bariatric surgery and during the 2 weeks following surgery. Changes in body weight will be
evaluated using weight measurement, BMI measurement and the percentage of excess weight loss
(% EWL), calculated using the formula: initial weight-actual weight/initial weight - (25 x
height2). Changes in diabetic status will be evaluated by HbA1c assay and collection of data
on anti-diabetic treatment maintained during the follow-up. The Ad-Diarem score for
predicting diabetes remission will be calculated in each patient from several variables
including age, diabetes duration, insulin use, other glucose-lowering agents used, number of
glucose-lowering agents used and HbA1c level. The variables recorded by CGM will include :
mean daily interstitial glucose concentration (mg/dL), standard deviation (SD) of glucose
concentration (mg/dL), coefficient of variation (CV) of glucose concentration corresponding
to the SD-to-mean daily interstitial glucose ratio, time in normoglycemia (ie in the
stringent 70-140mg/dL target which better reflects normoglycemia than the 70-180 mg/dl
target) or time in range (TIR) as a percentage over 24h, time spent in hyperglycemia (ie
>140mg/dL) or time above range (TAR) as a percentage over 24h, and time spent in hypoglycemia
(<70mg/dL) or time below range (TBR) as a percentage over 24h.
Judgement criteria are defined as follows: the success of bariatric surgery will be defined
as a % EWL >50%; normalization of glycemia will be defined as a mean 24-hr interstitial
glucose level <100mg/d during the CGM recording period; diabetes remission after metabolic
surgery will be defined as an HbA1c level at 1 year after surgery of < 6.0% without the use
of any glucose-lowering agent. Such thresholds were chosen to meet the definition of complete
remission by the American Society for Metabolic and Bariatric Surgery and the American
Diabetes Association.
Quantitative variables will be expressed as mean + standard deviation. Qualitative variables
will be expressed as percentages. Differences in quantitative variables, when compared to the
pre-operative period, will be examined using Students t-test for paired data or with ANOVA.
Analysis of subgroups will be carried out using Chi-2 test. Identification of predictive
factors for diabetes remission will be based on analysis of ROC curves and the calculation of
area under the curve data, sensitivity, specificity, positive predictive value (PPV),
negative predictive value (NPV), positive and negative likelihood ratio (LR+ and LR-) at
different thresholds for each study variable including the pre-operative and post-operative
CGM variables and the Add-Diarem score.