 Clinical trials using TZDs in type 2 diabetic subjects have observed that these agents also favorably impact plasma lipid and lipoprotein concentrations. A recent study comparing the efficacy of adding Metformin 850 mg, once or twice daily or Troglitazone 200 mg, once or twice daily to Glyburide 10 mg, twice daily on glycemic control in type 2 diabetic patients n22, reported that after 4 months of treatment, Metformin did not induce significant changes in LDL-C, LDL size, HDL-C, Triglycerides or Plasminogen Activator Inhibitor-1 PAI-1, but decreased C-reactive protein CRP by 33. Interestingly, Troglitazone increased the size of LDL and the mean LDL-C level 10, but decreased the Triglyceride -22 and CRP -60 concentrations 7. Following eight weeks of treatment with Rosiglitazone 4mg, twice daily in 243 type 2 diabetic patients, the mean HDL-C increased by 6 and TG by 2. The increase in the LDL-C concentration 9 was accompanied by a shift in small, dense LDL to large, buoyant LDL in 52 of the treated subjects. The shift in LDL size occurred independent of a significant Triglyceride reduction, which is in contrast to several studies reporting that increases in LDL size are significantly correlated with a decrease in the plasma concentrations of total and very low density lipoproteins VLDL Triglycerides 8-10. 