Hypertension patients who do not take their blood pressure medications systematically have a greatly increased risk of suffering a stroke and dying from it compared to those who take their medication correctly, a study has shown.

A study of 73,527 patients with high blood pressure, published online Wednesday in the European Heart Journal, found that patients who did not adhere to their medication had a nearly four-fold increased risk of dying from stroke in the second year after first being prescribed drugs to control their blood pressure, and a three-fold increased risk in the tenth year, compared with adherent patients.

"These results emphasise the importance of hypertensive patients taking their ant-hypertensive medications correctly in order to minimise their risk of serious complications such as fatal and non-fatal strokes," Dr Kimmo Herttua said.

Dr Herttua, the first author of the study, is a senior fellow in the Population Research Unit at the University of Helsinki, Finland.

"Non-adherent patients have a greater risk even 10 years before they suffer a stroke. We have also found that there is a dose-response relationship. The worse someone is at taking their anti-hypertensive therapy, the greater their risk," Herttua wrote.

The researchers, including scientists from Finland and University College London, UK, used nationwide registers in Finland that give details of prescriptions, admissions to hospital and deaths.