Missing doses of antihypertensive medication erase life-saving cardiovascular benefits

The true impact of missing doses of blood pressure-lowering medication will be demonstrated in a presentation at ESC Congress 2026.

Approximately 1.4 billion adults worldwide aged 30–79 years are estimated to have high blood pressure (hypertension), one of the most significant risk factors for disease burden. Despite the proven benefits of blood pressure-lowering medication in reducing cardiovascular events, around half of patients do not take them as prescribed.

We have evidence that poor adherence to antihypertensive medication is associated with worse outcomes. However, previous data has come from observational studies and could be confounded by other factors. We undertook an analysis of randomized trial data to assess the true impact of adherence on the benefits of antihypertensive treatment."

Miss Qianqian Yang, presenter, University of Oxford, UK

A meta-analysis was conducted of patient-level data from 91,339 participants in nine trials where an antihypertensive regimen (intervention group) was compared with another treatment (comparator group: either placebo or a less-intensive regimen). Participants who took at least 80% of their assigned treatment were classified as having higher adherence, while those who took less than 80% were classified as lower adherence.

"A decline in adherence over time was apparent, even in the structured setting of trials," noted Miss Yang. Overall, the proportion of patients classified as having higher adherence was 88% in the first year and only 79% by year five.

In patients with higher adherence, systolic blood pressure was reduced by 5.2 mmHg in the intervention group vs. the comparator group. In patients with lower adherence, the reduction was only 3.0 mmHg.

Next, the researchers studied the impact of adherence on major cardiovascular disease defined as stroke, myocardial infarction or ischaemic heart disease and heart failure causing death or hospitalisation. 

The incidence of major cardiovascular disease was significantly reduced by 11% in the intervention group vs. the comparator group in patients with higher adherence, but there appeared to be no significant reductions in patients with lower adherence.

"Notably, our results reinforce the saying that 'drugs don't work in patients who don't take them.' Patients with lower adherence derived little or no cardiovascular benefit, whereas those with higher adherence had greater reductions in blood pressure and prevention of cardiovascular events," said Miss Yang.

According to the authors, adherence assessment and education should be more prominent in hypertension management. In addition, strategies that help improve adherence should be promoted. These include simplifying regimens, using single-pill combinations to reduce the medication burden and using longer-acting agents where the effect of an occasional missed dose is less.

Commenting on the findings, Professor Felix Mahfoud, Chair of the ESC Communication Committee, said: "For years, we have neglected non-adherence to medication as a cause for uncontrolled hypertension. Assessment of adherence should become a routine part of hypertension care so patients do not miss out on life-saving benefits. As healthcare providers, we are here to have open, non-judgemental conversations with our patients about any barriers they may have to taking medication, to help improve adherence."