This was an observational, retrospective cohort study based on T2DM patients consecutively attending three diabetes outpatient clinics in Italy.
Two different cohorts were identified: the switch group consisted of patients already treated with another basal insulin before initiating IDeg; the add-on group consisted of basal insulin-naïve patients.
To minimize the selection bias, all consecutive patients who had started the treatment with IDeg (insulin-naïve subjects or switched to IDeg from another basal insulin) under routine clinical practice conditions were included in the study.
Baseline (i.e., IDeg start date, T0) patient characteristics included age, sex, body mass index (BMI), diabetes duration, glucose-lowering treatment, and diabetes-related complications. Chronic kidney disease was defined as an estimated glomerular filtration rate below 60 ml/min (CKD-EPI formula).
Data on glycated hemoglobin (HbA1c), fasting blood glucose (FBG), post-prandial glucose (PPG), standard deviation of mean blood glucose (glycemic variability), body weight, doses of basal and short-acting insulin, and overall, nocturnal, and severe hypoglycemia episodes was collected at baseline visit and during the two subsequent follow-up visits, scheduled according to the routine clinical practice (T1 and T2).
HbA1c levels were measured in the hospital laboratories, all adopting standardized methods (DCCT-aligned HbA1c method).
Data was acquired from electronic medical records.
Downloaded blood glucose data from glucose meters routinely used by the patients providing data on FBG, PPG, glycemic variability, and hypoglycemia included all the values recorded during the last 3 months before each visit. Overall hypoglycemia was defined as all blood glucose values less than 70 mg/dl, severe hypoglycemia as a hypoglycemia episode requiring assistance by a third person. Nocturnal hypoglycemia was defined as blood glucose value less than 70 mg/dl recorded between midnight and 7.00 a.m.
The study protocol was approved by local ethics committees and all patients signed the informed consent. All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1964, as revised in 2013.
All data was stratified by treatment type (switch group; add-on group).
Descriptive data was expressed as mean ± standard deviation (SD) for continuous variables, and percentage for categorical variables.
Longitudinal linear models for repeated measures were applied to assess trends over time in continuous endpoints (HbA1c, FBG, PPG, glycemic variability, weight, insulin dose). All longitudinal models take into consideration three time points, i.e., T0, T1, and T2. Only for insulin doses, an additional time point was considered (T − 1, corresponding to the last prescribed dose of the previous basal insulin before the initiation of IDeg). For all longitudinal models, an unstructured correlation type was used to account for within-patient correlation over time and unequal follow-up. Results were expressed as estimated mean and estimated mean change from baseline with their 95% confidence intervals (CIs), and p values less than 0.05 were considered statistically significant.
Proportions of patients with at least one hypoglycemic episode were assessed at three time points, i.e., during 3 months before IDeg start date (T0), during 3 months before the first follow-up visit (T1), and during 3 months before the second follow-up visit (T2).
All statistical analyses were performed with SAS software release 9.4 (SAS Institute, Cary, NC, USA).