- Patients The objective of the present study is to demonstrate that telematic control of diabetes mellitus is not inferior to the face to face visit control system, while showing an added value an important reduction in costs. Cost information from three studies have been used for the calculation of the sample 2,3,20 in diabetes mellitus 1 (DM1) patients, some followed in a telematic form (210 ± 184€) and other in the form of face to face visits (376 ± 278€). Relating to this, 72 patients per group are needed to obtain a statistical power of 99% and an alpha level of 0.05 (two-sided). 80 patients per group will be needed to be randomised taking into account a 10% loss percentage.