Joint science advisory issues messages for diabetics at risk for heart disease and stroke

The data are inconclusive on heart risks from a class of blood sugar-lowering drugs called thiazolidinediones (TZDs) such as pioglitazone (Actos) or rosiglitazone (Avandia), but the medications should be used with close monitoring from healthcare providers according to a joint science advisory from the American College of Cardiology and the American Heart Association.

The advisory is published online in both Circulation: Journal of the American Heart Association and Journal of the American College of Cardiology.

The U.S. Senate Finance Committee released a report on Saturday following a two-year inquiry into the safety of the diabetes drug rosiglitazone, and the possibility of an increased incidence of adverse cardiovascular events.  Resulting news coverage has highlighted uncertainties about research on TZDs.  

"Research is ongoing and more is needed to understand which agents, including TZDs, work best for diabetes control," said Clyde Yancy, M.D., president of the American Heart Association.  

The purpose of the advisory is to summarize the currently available data concerning TZDs and cardiovascular risk, and provide practical recommendations to healthcare workers seeking to minimize the burden of cardiovascular disease and other complications in their patients with type 2 diabetes mellitus.

"Science is constantly evolving and physicians should carefully evaluate all research on this topic," said Alfred A. Bove, M.D., president of the American College of Cardiology. "Patients should feel comfortable bringing any medical concerns to their physicians."

"Patients with diabetes are at increased risk for heart disease and stroke and should adopt comprehensive treatment strategies that include diet, activity and a medical regimen that works best to achieve optimal control of blood sugar," Yancy added.  "A good relationship with a care provider is the best step for any patient with diabetes to take."

Take-away messages for patients with diabetes:

• Focus on glycemic (blood sugar) control keeping your HbA1c levels below 7.0% to reduce the risk of the "microvascular" complications of diabetes, such as kidney failure, painful nerve problems, and decreased vision or even blindness.
• The cornerstone of treatment should be healthy lifestyle choices (a healthy diet and regular physical activity) and optimal control of blood pressure and lipids (such as cholesterol and triglycerides).  An aspirin regimen should be used under the advice of a physician in patients who have known cardiovascular disease due to atherosclerosis.
• With regards to glucose-lowering medications,
  • Metformin should generally be the first choice, particularly in obese patients.  If it does not produce adequate HbA1c control, other medications can be considered, recognizing that the fund of knowledge about the effect of other glucose-lowering agents on cardiovascular risk is sparse.
  • If a TZD (such as pioglitazone or rosiglitazone) is considered for this purpose, it should not be used with an expectation of benefit in reducing the occurrence of heart attack or stroke, and the rationale for the choice of a TZD should be discussed with your physician.  However, patients who have successfully achieved recommended HbA1c control on a TZD might consider remaining on their medication.  If the treating physician and/or the patient is uncomfortable with using a TZD, another medication could be substituted.  There is currently not enough data to support the choice of a specific TZD.

According to the joint advisory:

• Diabetes mellitus is increasing in prevalence in the United States and worldwide.  An estimated 23.6 million people in the United States, 7.8% of the population, had diabetes in 2007, with more than 90% of cases being type 2 diabetes mellitus.
• Diabetes increases the risk of CVD events by 2- to 4-fold, and CVD accounts for nearly two thirds of deaths among diabetic patients.
• Among people who experience CVD events, diabetes is highly prevalent: 45% of those hospitalized for heart attack have known or previously undiagnosed diabetes.
• Diabetes is also an independent predictor of secondary adverse events, such as reinfarction, heart failure, and death.

Advisory writing committee members include Sanjay Kaul, M.D., Chair; Ann F. Bolger, M.D.; David Herrington, M.D.; Robert P. Giugliano, M.D., ScM and Robert H. Eckel, M.D.  Author disclosures are on the manuscript.