When patients with high blood pressure fail to take their blood pressure medication as directed it puts them at an even greater risk of having a stroke and having fatal consequences.

“These results emphasize the importance of hypertensive [high blood pressure] patients taking their anti-hypertensive medications correctly in order to minimize their risk of serious complications such as fatal and non-fatal strokes,” said study first author Dr. Kimmo Herttua, a senior fellow in the Population Research Unit at the University of Helsinki in Finland. The worse someone is at taking their blood pressure medication, the greater risk they have for suffering strokes.

For the study, distributed online July 17 in the European Heart Journal, specialists studied more than 73,000 hypertensive Finnish patients, ages 30 and up, from 1995 through 2007. The study had some limitations. The researchers couldn’t be sure that patients were actually taking the blood pressure medication even though they had picked it up, and the registries did not offer information on body mass index, smoking, alcohol consumption and resting blood pressure.

The researchers took a look at how frequently blood pressure medication was filled for these patients every year to confirm if they followed their medication regimens. Throughout this time, more than 2,100 died from stroke and more than 24,500 were hospitalized with a stroke. Compare to the patients who followed their blood pressure medication schedule, those who didn’t follow the schedule had almost four times the risk of dying from a stroke in the second year afater being prescribe the medication and three times the risk in the 10th year.

The study also found that in the actual year that non-adherent patients died from stroke, they had a 5.7-fold higher risk than those patients who followed the blood pressure medication schedule. Patients who didn’t take their blood pressure-lowering medications correctly had a 2.7-fold higher risk of hospitalization in the second year after being prescribed the drugs, and a nearly 1.7-fold higher risk in the tenth year.

“As far as we know, this study is unique as it is the first study to follow patients over a long period of time, repeatedly checking how correctly they are taking their medications, and linking the trajectory of adherence with the risk of fatal and non-fatal stroke,” Herttua said in a journal news release.