Annie Yan

Although the medical community has long assumed that hypertension drugs are equal in safety and efficacy, a recent Yale-affiliated study found that these medications carry different risks.

Co-author and Yale professor Harlan Krumholz ’80 said that in general, health care providers have assumed the four classes of hypertension drugs — thiazides, calcium channel blockers, ACE inhibitors and angiotensin receptor blockers — are equal in efficacy and safety. But there has not been a randomized control trial on hypertension drugs since 2009, and so providers are prescribing medications based on outdated research. The new research suggests thiazides are the safest hypertension medication available, but are currently underprescribed.

“[We were] looking for a clinical domain where randomized trials left open large gaps in our knowledge about treatment choices,” said Marc Suchard, co-author and UCLA professor. “The comparative effectiveness of anti-hypertensive drugs stood fortuitously at this intersection.”

The team completed an observational analysis of 4.9 million patients in four different countries. Researchers gathered information such as patient medical history, prescribed hypertension medication and subsequent adverse cardiac events to investigate the risk profiles of the different medications for high blood pressure.

After controlling for variations across the many patients, researchers evaluated the drug classes for safety and effectiveness. Though angiotensin receptor blockers are the most commonly prescribed medication type, they found that thiazides were the safest and most effective while calcium channel blockers exhibited the least effective outcomes. Patients who were prescribed a thiazide had a significantly decreased risk of heart attacks and hospitalizations related to heart failure and stroke.

The research stated that if the 2.4 million people who were prescribed an angiotensin receptor blocker had instead taken a thiazide, 3,100 major adverse cardiac events might have been prevented.

The findings, according to co-author and Columbia professor George Hripcsak, will likely lead to increased thiazide prescriptions.

“Thiazides are excellent drugs … so this study may encourage the emphasis on [thiazides] to move outside the medical centers to more common practice,” Hripcsak said.

Still, future research should better control for changes in patient’s health, according to Alexandra Lansky, director of the Yale Cardiovascular Research Center, who was not involved with the study. Lansky said factors such as drug compliance and new medical diagnoses were difficult to capture with the study’s observational design and warrant further testing to control for this information.

With the study’s complex design in place, Krumholz encouraged the use of its findings to accelerate future research in hypertensive treatment.

“Now that we have this set up, we should really push it to have maximum benefit for society because we can ask a lot of questions now and learn quickly,” Krumholz said.

29 percent of Americans have high blood pressure.


Savannah Kucera |