Give people free prescription drugs and many of them still won’t bother to take their medicine.

Doctors were stunned to see that happen in a major study involving heart attack survivors. The patients were offered well-established drugs to prevent a recurrence of heart trouble, including cholesterol-lowering statins and medicines that slow the heart and help it pump more effectively.

“My God, we gave these people the medicines for free and only half took it,” said one of the study’s authors, Dr. Elliott Antman of Harvard-affiliated Brigham and Women’s Hospital in Boston.

In fact, the researchers couldn’t even give the stuff away: they had trouble just signing up patients to take part in the study.

Nevertheless, Aetna, the insurance company that footed the bill, thinks this approach will save money in the long run and plans to start offering certain heart drugs free to some patients. In the study, patients offered medicines at no cost suffered fewer heart problems and saved $500 on average over roughly a year.

It is no secret many Americans don’t follow their doctors’ instructions. In one survey, one-third said they didn’t fill a prescription or used less medicine than they should because of cost. The researchers in the study wanted to see what would happen if they took cost out of the equation.

The results were disheartening.

“Adherence in America is miserable,” lamented Dr. Eric Peterson of Duke University, who had no role in the study. He noted that only 10 percent of the patients were taking all the medicines they should one year after a heart attack.

Dr. Kathryn Glass, a primary care doctor at Lourdes hospital in Paducah, said people come to her office wanting a single pill to fix a lifestyle problem like obesity or smoking rather than making the change themselves.

“When people are told they have to take another pill, they don’t want to take it. Like with diabetes, they don’t want to take a medication, but are unwilling to lose 20 pounds to make the pill unnecessary. If we had a pill that did things like weight loss or stop smoking without a lifestyle change, a patient would never stop taking it,” Glass said.

She added patients who experience a heart attack may be likely to take essential medications at first. Months or years removed from the scare, they may grow lax about their medication.

The study was led by Dr. Niteesh Choudhry of Brigham and Women’s, who presented the findings in late November at an American Heart Association conference in Florida. They also were published online by The New England Journal of Medicine.

Dr. Patrick Withrow, a cardiologist and chief medical officer at Western Baptist Hospital in Paducah, said physicians at the hospital did not participate in the study, but often offer drug samples.

“What is a part of non-compliance is a lack of motivation, and that may come from a lack of meaningful patient education about the need for these drugs,” Withrow said.  “The reason people give us for not taking drugs is their expense. A drug company footed the bill, and they still didn’t take their medicines. It’s like the number of patients I see that have heart bypasses who smoke; you tell them to quit, but they keep on smoking.”