Allocation concealment and blinding
Patients were randomized sequentially
at study level according to a predefined
computer-generated randomization scheme
provided by AstraZeneca. Allocation of
study treatments was performed via an
Interactive Web Response System in balanced
block sizes of 4to ensure approximate
balance among treatment groups. Blinding
of patients and investigators to study treatment
was achieved using a double-dummy
technique. Metformin was administered as
an open-label treatment throughout the
study