Adolescents with type 1 diabetes vs. hybrid closed loop systems: a case series of patients’ behaviour that challenges the algorithm.

Hybrid closed loop systems (HCL) improve the management of type 1 diabetes (T1DM). T1DM adolescent patients represent a risk category also if they are in an automated insulin infusion delivery therapy.We describe a series of four cases in which adolescent patients have adopted incorrect behaviours in the managing of HCL systems, challenging the algorithm skills. Two patients performed fabricated sensor calibrations. The other two did not perform pre-prandial insulin boluses correctly. Despite these behaviours, the algorithm corrected the glucose values in three out of four patients. Only in one case, where fabricated calibrations were too frequent, the automatic system failed to restore the glycemic balance.Fabricated calibrations seem to be more important than uncorrected insulin boluses to challenge the HCL systems.