INS and type 1 diabetes mellitus: An additional source of controversy is the difficulty to define metabolic syndrome in patients with T1D; since all patients are diabetic, this may represent a selection bias and possibly overdiagnosis; also, the most important feature of MS (insulin resistance) is not part of the pathogenesis of T1D and, finally, the use of exogenous insulin in T1D makes it impossible to predict insulin resistance with simple methods such as the HOMA-IR index calculation.