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Valsartan does not improve clinical outcomes in impaired glucose tolerance (NAVIGATOR)

Clinical Question:
Does valsartan reduce cardiovascular end points or mortality in patients with impaired glucose intolerance?

Bottom Line:
Valsartan slightly reduces the risk of being diagnosed with diabetes 5 years later in patients with glucose intolerance. At $1000 per year for valsartan, the cost to prevent 1 diagnosis of diabetes over 5 years is $135,000. The drug becomes generic in 2012. Lifestyle modification remains the treatment of choice for this group of patients. (LOE = 1b)

Reference:
The NAVIGATOR Study Group. Effect of valsartan on the incidence of diabetes and cardiovascular events. N Engl J Med. 2010 Mar 29. [Epub ahead of print]  [PMID:20228403]

Study Design:
Randomized controlled trial (double-blinded)

Funding:
Industry

Allocation:
Concealed

Setting:
Outpatient (any)

Synopsis:
Although previous studies have shown that drugs inhibiting the renin-angiotensin system may reduce the risk of diabetes in patients with impaired glucose tolerance, we don't know whether medical intervention in this group makes any difference in patient-oriented outcomes. The current study is part of a 2-way randomized controlled trial that also studied nateglinide for the same indication. The authors identified patients (N = 9306) with a fasting glucose between 95 mg/dL and 126 mg/dL (5.3 - 7.0 mol/L) and also had a cardiovascular risk factor (if older than 55 years) or cardiovascular disease (if older than 50 years). All patients also received a lifestyle intervention. The mean age of patients was 64 years, half were women, 83% were white, approximately 25% had known cardiovascular disease, and their mean glycated hemoglobin was 5.8%. Patients were randomized to receive valsartan (80 mg initially, increasing to 160 mg after 2 weeks), nateglinide, both, or neither. The analysis compared patients randomized to receive valsartan versus placebo since half in each group were also taking nateglinide. Overall, the groups were balanced at the start of the study, analysis was by intention to treat, and patients were followed up for a mean of 5 years. Although approximately 20% of patients were lost to follow-up or withdrew from the study, this number did not differ between study groups. After 5 years, patients taking valsartan were a bit less likely to be diagnosed with diabetes than those in the placebo group (33.1% vs 36.8%; P < .001; number needed to treat for 5 years = 27). However, there was no difference in any individual cardiovascular end point (ie, cardiovascular death, myocardial infarction, stroke, hospitalization, revascularization) or in death, or even in prespecified combinations of cardiovascular outcomes.

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