Derek Weycker, PhD, senior consultant, Policy Analysis Inc., Brookline, Massachusetts, and colleagues compared the risk of new-onset diabetes among 28,697 hypertensive patients who were at least 35 years of age and free of diabetes who initiated therapy with valsartan or amlodipine in a real-world setting.

"Recent evidence suggests that the risk of diabetes among patients with hypertension may differ based on antihypertensive therapy received," Dr. Weycker said on May 17^th.

The Valsartan Antihypertensive Long-Term Use Evaluation (VALUE) trial was the first large, randomized trial to compare diabetes risk between patients receiving an angiotensin-receptor blocker versus a calcium antagonist. Over a mean follow-up of 4.2 years, the risk of diabetes was 11.5% for valsartan versus 14.5% for amlodipine; the odds ratio was 0.77 in favor of valsartan.

Whether or not this finding holds true in the real-world setting has not been determined, Dr. Wycker said.

The present investigation used information from an integrated database of medical and outpatient pharmacy claims from 49 U.S. health plans with 15 million covered lives annually. The data spanned the period January 1998 through March 2005.

New-onset diabetes was identified based on at least 2 outpatient diagnoses at least 7 days apart, at least 1 inpatient diagnosis, or at least 1 prescription for an anti-diabetic medication.

Over a mean follow-up of 407 days, 2.4% of valsartan patients developed diabetes; the corresponding figure for amlodipine was 3.3% over a mean follow-up of 460 days.

At the end of 1 year, the unadjusted risk of diabetes was 2.4% for valsartan versus 2.9% for amlodipine; at the end of 3 years, corresponding risks were 5.6% and 6.8%.

In Cox proportional hazards regression, the relative risk of diabetes for patients receiving valsartan versus amlodipine was.0.79.

Dr. Weycker said that any interpretation of the results needs to consider the fact that the study was based on healthcare claims data. Limitations include coding errors and missing information on clinically important parameters such as blood pressure, blood glucose, body weight that may affect the risk of diabetes.

He added that the biological basis for this difference in diabetes risk has not yet been well characterized.

The study was sponsored by Novartis Pharma AG in Basel, Switzerland.


[Presentation title: Risk of Diabetes in Hypertensive Patients Receiving Amlodipine Versus Valsartan. Abstract P-229]

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