We thought the answer was YES or CAN'T TELL.
The decision tree/s can be identified unambiguously. However, you may have found this hard work because it is not explicitly stated. The implicit decision tree for each analysis (glycaemic control, control of hypertension, and control of cholesterol) has a decision node with two branches: intensive treatment and conventional treatment.
In the description of drugs for hyperglycaemia they do not mention metformin, this is commonly used in the UK so the interventions given may not reflect current practice.
The intervention and other details are not fully defined but the authors refer to the UKPDS and the NHANESIII. They also give all the information in a technical document available from the authors. The CASP International Network has a copy of this document, which was received from the authors two days after its request by email.