CHICAGO – New research suggests giving patients easier-to-take medicine and no-copay medical visits can help drive down high blood pressure, a major contributor to poor health and untimely deaths nationwide.

Those efforts were part of a big health care provider's eight-year program, involving more than 300,000 patients with high blood pressure. At the beginning, fewer than half had brought their blood pressure under control. That increased to a remarkable 80 percent, well above the national average, the researchers said.

The research involved Kaiser Permanente in Northern California, a network of 21 hospitals and 73 doctors' offices, which makes coordinating treatment easier than in independent physicians' offices.

The number of heart attacks and strokes among Northern California members fell substantially during roughly the same time as the 2001-09 study. Dr. Marc Jaffe, the lead author and the leader of a Kaiser heart disease risk ­reduction program, said it's impossible to know if the blood pressure program can be credited for those declines, but he thinks it at least ­contributed.

Reductions continued even after the study ended; in 2011, 87 percent of roughly 350,000 Kaiser patients had recommended blood ­pressure levels.

The study was published Tuesday in the Journal of the American Medical Association.

"What's unique about this is the sheer scale of what they've done," said Dr. Goutham Rao, a family medicine specialist at NorthShore University HealthSystem, a group of four hospitals in Chicago's northern suburbs. Rao is involved in research on reducing obesity and other risks for heart disease.

"If we were able to keep everyone's blood pressure under control in the United States, the number of new strokes and heart attacks would go down just exponentially," he said.

High blood pressure affects 1 in 3 U.S. adults, or 67 million people, and the condition caused or contributed to more than 348,000 deaths in 2009, according to the Centers for Disease ­Control and Prevention.

Normal blood pressure is considered a reading of less than 120 over 80; high blood pressure is 140 over 90 or higher.