Effect of metformin plus roziglitazone compared with metformin alone on glycaemic control in well‐controlled Type 2 diabetes

Abstract

To investigate the effect of metformin plus roziglitazione (RSGMET) compared with metformin alone (MET) on glycaemic control in well-controlled Type 2 diabetes. Subjects (drug naïve or those on glucose-lowering monotherapy) were randomized (n = 526), following a 4-week placebo run-in period, to RSGMET [4 mg rosiglitazone (RSG)/500 mg MET] or MET 500 mg. From weeks 2-18, medication was escalated every 4 weeks (based on gastrointestinal tolerability), then remained at RSGMET 8 mg/2 g or MET 3 g for 14 weeks. RSGMET reduced HbA(1c) from 7.2 +/- 0.6 to 6.7 +/- 0.8% at week 32, compared with a reduction from 7.2 +/- 0.6 to 6.8 +/- 0.9% with MET (treatment difference -0.13%; P = 0.0357). More subjects achieved an HbA(1c) value of </= 6.5% at week 32 with RSGMET (51.6 vs. 43.7%), but the treatment difference was not significant (odds ratio 1.37, P = 0.0949). RSGMET produced larger reductions from baseline in mean fasting plasma glucose (adjusted difference -0.62 mmol/l, P < 0.0001), with the odds ratio of achieving a target of < 7.0 mmol/l being 2.33 (P < 0.0001). Statistically significant differences in favour of RSGMET relative to MET were seen for homeostatic model assessment (HOMA)-derived estimates of insulin sensitivity and pancreatic B-cell function, C-reactive protein (CRP), and systolic blood pressure. Overall rates of gastrointestinal adverse events (relevant to the known profile of MET) were comparable, but with a lower incidence of diarrhoea (8 vs. 18%) with RSGMET. Hypoglycaemia was reported in </= 7% subjects per group. RSGMET provided similar short-term glycaemic control to MET with greater improvements in estimates of insulin sensitivity, B-cell function and CRP, with less diarrhoea and low risk of biochemical hypoglycaemia, suggesting that early use of combination therapy may be appropriate.