(Reuters Health) - People who seem healthy after a heart attack remain at high risk for another one, but many don't take the drugs that can improve their survival odds, researchers say.

Swedish investigators studied heart attack patients who remained stable for the first year after leaving the hospital. One in five had another heart attack, a stroke or died from cardiovascular causes during the next three years.

"We were surprised that the risk of future cardiovascular events in these patients was still high," said lead study author Dr. Tomas Jernberg, a cardiologist at Karolinska University Hospital in Stockholm. "We need to follow and support these patients more carefully."

Jernberg's team analyzed outcomes for 97,254 patients who had heart attacks between 2006 and 2011 and survived for at least a week after leaving the hospital. A year later, 76,687 of those patients were considered "stable" because they hadn't had another heart attack or a stroke.

Overall, the researchers found, the stable patients were likely to be younger, with fewer other serious health conditions, than the unstable patients. They were also slightly more likely to have had an aggressive intervention right after the first heart attack, such as angioplasty to clear a blocked artery.

Yet in the three years following an initial stable year, 20 percent had another heart attack, stroke or other cardiovascular event. Of these, 41 percent died from a cardiovascular cause.

The Swedish team also found that after the first year, stable patients were less likely to be on the standard medications used to manage heart patients.

It's unclear whether doctors treating these seemingly healthier heart attack survivors were not prescribing the correct medications according to practice guidelines, or they were, and patients were not taking them.

The research, published in the European Heart Journal, was supported by AstraZeneca PLC, which sells several medications for cardiovascular disease. Two co-authors are AstraZeneca employees.

It's common for people to resist drugs when they don't understand the benefits, said Dr. Lisa Rosenbaum, a cardiologist at Brigham and Women's Hospital in Bostonwho recently published an essay in the New England Journal of Medicine about patients' feelings toward heart medications.

"In the days immediately after a heart attack, so many people will look you right in the eye and say, 'Doctor, I'll do whatever you say and I'm going to change my life,' but the real question is what happens later," said Rosenbaum, who wasn't involved in the Swedish study.

Some people may reject the notion of medications because if they don't take pills, they don't feel like they're sick, she said. Others may be scared of side effects. Still others may associate drugs with unhealthy lifestyle choices that contribute to heart disease and feel ashamed to take medication.

"There isn't a silver bullet to fix this, but I think we need to focus on improving communication and removing any stigma that people may feel," Rosenbaum said. "We need to go old school and actually make time to talk to patients, which isn't something we can do in a five- or 10-minute appointment."

Dr. Jeffrey Schussler, a cardiologist at Baylor Jack and Jane Hamilton Heart and Vascular Hospital in Dallas, agreed that most patients will stick to recommended treatment if they clearly understand the benefits.

"In my experience, 95 percent of people are compliant, and then there will be 5 percent who smoke and drink and don't listen," said Schussler, who wasn't involved in the Swedish study.

While medications certainly help patients remain stable after a heart attack, he said that for many, the outcome will depend on whether they continue to see a heart specialist after going home from the hospital.

"Even if it's just once a year, you really need to see a cardiologist," Schussler said. "There can be a temptation after you're stable for a while to just see a primary care physician, but that's a mistake."

SOURCE: European Heart Journal, online January 13, 2015 and New England Journal of Medicine, January 8, 2015.