Table 1 Summary of the efforts to define the classification criteria for double diabetes

Teupe et al.

1991

• Diagnosed T1D

• At least one relative suffering from T2D

[3]

Gilliam et al.

2005

• Atypical individuals or subjects with clinical features characteristic for both T1D and T2D at the presentation

• Doubts about the proper diagnosis

[13]

Pozzilli et al.

2007

• Clinical features of T2D, such as:

o Excessive body weight

o Dyslipidaemia

o Hypertension

o Increased risk of cardiovascular diseases

• Reduced number of typical clinical features of T1D, such as:

o Polyuria

o Polydipsia

o Loss of weight

o Ketoacidosis

• Always obesity

• Presence of autoantibodies against pancreatic β-cells in a reduced number and titre

• Presence of family history of T1D or T2D (but not necessarily always present)

[14]

Cleland

2012

• Diagnosed T1D

• Features characteristic for T2D, such as:

o Relatively high doses of insulin needed to maintain appropriate glucose levels

o Weight gain during insulin treatment

o Presence of hypertension

o Presence of IR (understood as low eGDR)

o Low concentration of HDL-C

o Family history of T2D, especially in at least 2 relatives

[15]

Kietsiriroje et al.

2019

• Diagnosed T1D

• Family history of T2D

• Presence of overweight, metabolic syndrome

• Clinical features of insulin resistance – especially eGDR < 8

[16]