An estimated 1.4 billion adults ages 30 to 79 worldwide have high blood pressure. Although medicine lowers the risk of serious heart and blood vessel problems, about half of patients do not take it as prescribed.
Researchers analyzed 91,339 participants across nine clinical trials comparing blood pressure treatment with another approach. Patients had higher adherence, meaning they followed treatment more closely, if they took at least 80% of their assigned medicine. The share reaching this level fell from 88% in year one to 79% in year five, despite regular monitoring.
Among patients with higher adherence, treatment lowered systolic blood pressure—the top number in a reading—by 5.2 mmHg compared with the comparison group. The difference was only 3.0 mmHg among those with lower adherence. Treatment was also linked to 11% fewer major cardiovascular events among higher-adherence patients. These included heart attacks and strokes. Among lower-adherence patients, the reduction was not statistically significant, meaning it was not clearly distinguishable from chance.
Researchers recommend checking medicine use routinely and improving patient education. Simpler schedules, combining medicines into one pill, and longer-acting drugs could make treatment easier to follow. They also encourage health workers to discuss difficulties openly, without judging patients.
