Reductions in biomarkers of cardiovascular risk in type 2 diabetes with rosiglitazone added to metformin compared with dose escalation of metformin: an EMPIRE trial sub-study.

OBJECTIVE: To compare the effects of rosiglitazone added to metformin with dose escalation of metformin on cardiovascular risk biomarkers in type 2 diabetes mellitus.

RESEARCH DESIGN AND METHODS: Cardiovascular biomarkers were assessed in a sub-population of 122 subjects with type 2 diabetes mellitus (mean age 54.6 and 56.0 years, BMI 34.7 and 32.1 kg/m2; for the rosiglitazone plus metformin and metformin groups, respectively) from the multicenter (63 centers in the USA), double-blind, randomized parallel-group Escalation of Metformin theraPy vs. Initiation of Rosiglitazone Early (EMPIRE) study. Treatment group sizes were slightly imbalanced owing to central, rather than local, randomization. Subjects receiving metformin 1000 mg/day at baseline were randomized to rosiglitazone 4 mg/day plus metformin 1000 mg/day (RSG + MET) or metformin 1500 mg/day (up-titrated MET) for 24 weeks. At 8-weeks, rosiglitazone was increased to 8 mg/day in RSG + MET recipients and metformin to 2000 mg/day in up-titrated MET recipients.

RESULTS: Reductions from baseline in HbA1c at week 24 (mean +/- SD) occurred in both groups (RSG + MET: -0.61% +/- 1.16%; up-titrated MET: -0.65% +/- 1.18%). Post-prandial glucose levels (AUC(0-3h)) decreased with RSG + MET (-3.5 mmol/L.h; 95% confidence interval [CI]: -5.2 to -1.8) and up-titrated MET (-1.3 mmol/L.h; 95% CI: -3.8 to 1.1). Homeostasis Model Assessment (HOMA)-estimated insulin sensitivity increased by 37.7% (95% CI: 22.8 to 54.5) in RSG + MET and 6.9% (95% CI: -6.2 to 21.9) in up-titrated MET recipients. RSG + MET reduced C-reactive protein (CRP; -23.9%; 95% CI: -40.4 to -2.8), plasminogen activator inhibitor-1 (PAI-1) activity (-30.1%; 95% CI: -44.5 to -11.9), PAI-1 antigen (-15.5%; 95% CI: -28.3 to -0.3) and matrix metalloproteinase-9 (MMP-9; -13.8%; 95% CI: -25.1 to -0.9), but increased tumor necrosis factor-alpha (TNF-alpha; 27.0%; 95% CI: 6.8 to 50.9). Corresponding values for up-titrated MET were CRP -9.3% (95% CI: -36.9 to 30.2), PAI-1 activity -7.2% (95% CI: -28.2 to 20.0), PAI-1 antigen -1.5% (95% CI: -17.4 to 17.5), MMP-9 29.0% (95% CI: -1.3 to 68.6) and TNF-alpha -6.0% (95% CI: -22.0 to 13.2).

CONCLUSIONS: These results suggest that rosiglitazone plus metformin has positive cardiovascular effects against a background of similar glycemic improvements.