INS and type 2 diabetes mellitus: Hence, the primary outcome measure of the underlying double-blind, multi-centre, randomized, parallel three-arm trial was to investigate the effect of pioglitazone in comparison to metformin and the combination of both on MMP-9 together with a spectrum of established risk factors and biomarkers of inflammation during a 6-month therapy in type 2 diabetes patients pre-treated with insulin in order to use the generated data for evaluation of possible beneficial effects of comparator drugs as add-on treatment on cardiovascular risk.