Background and Purpose— Diabetes is an important risk factor for stroke. We conducted analyses in patients who had entered the PROspective pioglitAzone Clinical Trial In macroVascular Events (PROactive) with a history of stroke or without stroke. Methods— The prospective, double-blind PROactive (mean duration, 34.5 months) randomized 5238 patients with type 2 diabetes and a history of macrovascular disease to pioglitazone (titrated to 45 mg) or placebo, in addition to current diabetes and cardiovascular medications. Cardiovascular end-point events were independently adjudicated. This analysis evaluated the risk of stroke and other cardiovascular outcomes in patients with (n=984) and without (n=4254) prior stroke. Results— In patients with previous stroke (n=486 in the pioglitazone group and n=498 in the placebo group), there was a trend of benefit with pioglitazone for the primary end point of all-cause death, nonfatal myocardial infarction, acute coronary syndrome, and cardiac intervention (including coronary artery bypass graft or percutaneous coronary intervention), stroke, major leg amputation, or bypass surgery or leg revascularization (hazard ratio[HR]=0.78, event rate=20.2% pioglitazone vs 25.3% placebo; 95% CI=0.60–1.02; P =0.0670) and for the main secondary end point of all-cause death, nonfatal myocardial infarction, or nonfatal stroke (HR=0.78, event rate=15.6% pioglitazone vs 19.7% placebo; 95% CI=0.58–1.06; P =0.1095). Pioglitazone reduced fatal or nonfatal stroke (HR=0.53, event rate=5.6% pioglitazone vs 10.2% placebo; 95% CI=0.34–0.85; P =0.0085) and cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke (HR=0.72, event rate=13.0% pioglitazone vs 17.7% placebo; 95% CI=0.52–1.00; P =0.0467). Higher event rates were observed in patients with prior stroke compared with those without prior stroke. In patients without prior stroke, no treatment effect was observed for a first stroke. Conclusions— In a subgroup analysis from PROactive, pioglitazone reduced the risk of recurrent stroke significantly in high-risk patients with type 2 diabetes.

Ewan Pearson, Kathleen Giacomini and the Metformin Genetics Consortium perform a genome-wide association study for glycemic response to the antidiabetic drug metformin. They find an intronic allele of the GLUT2 glucose transporter gene that associates with greater metformin action, an effect that is more pronounced in obese individuals. Metformin is the first-line antidiabetic drug with over 100 million users worldwide, yet its mechanism of action remains unclear1. Here the Metformin Genetics (MetGen) Consortium reports a three-stage genome-wide association study (GWAS), consisting of 13,123 participants of different ancestries. The C allele of rs8192675 in the intron of SLC2A2, which encodes the facilitated glucose transporter GLUT2, was associated with a 0.17% (P = 6.6 × 10−14) greater metformin-induced reduction in hemoglobin A1c (HbA1c) in 10,577 participants of European ancestry. rs8192675 was the top cis expression quantitative trait locus (cis-eQTL) for SLC2A2 in 1,226 human liver samples, suggesting a key role for hepatic GLUT2 in regulation of metformin action. Among obese individuals, C-allele homozygotes at rs8192675 had a 0.33% (3.6 mmol/mol) greater absolute HbA1c reduction than T-allele homozygotes. This was about half the effect seen with the addition of a DPP-4 inhibitor, and equated to a dose difference of 550 mg of metformin, suggesting rs8192675 as a potential biomarker for stratified medicine.