Researchers studied patients with IGT, as well as either CVD or a cardiovascular risk factor, who were undergoing lifestyle interventions. They found that, for every 1,000 patients, treatment with the ARB valsartan led to 38 fewer cases of diabetes.
Studies have suggested that the inhibition of the renin- angiotensin system may reduce incidence of diabetes among people with hypertension and CVD. But it is unknown whether this also benefits IGT patients, who have increased risk of type-2 diabetes.
Dr Robert Califf and colleagues from Duke University, North Carolina, examined the effect of valsartan and the glucose regulator nateglinide on risk of diabetes and cardiovascular events.
A total of 9,306 patients with IGT were randomised to receive valsartan or placebo, plus nateglinide or placebo. All participated in a lifestyle intervention programme to lose weight, reduce fat intake and increase physical activity.
In the course of the five-year study, 33 per cent of patients developed diabetes in the valsartan group compared with 37 per cent in the placebo group.
The researchers concluded that taking valsartan reduced the risk of developing diabetes by 14 per cent when added to lifestyle intervention in patients with IGT. Lifestyle intervention alone reduced diabetes risk by 58 per cent.
But they found no effect of the drug on cardiovascular events in those with CVD or risk factors. Nateglinide failed to reduce diabetes or cardiovascular events.
The authors said: 'Our findings may have implications for the treatment of hypertension, since the use of both thiazide diuretics and beta-blockers has been associated with an increased risk of diabetes.'