Patients who do not take blood pressure-lowering medication as prescribed are deriving little-to-no therapeutic benefit in cardiovascular disease, research shows.
The study, full data of which will be presented at the upcoming European Society of Cardiology (ESC) Congress in Munich, Germany, is the first of its kind to demonstrate the true impacts of missing doses of medication designed to treat hypertension.
The study was funded by the British Heart Foundation and led by professor Kazem Rahimi and Dr Milad Nazarzadeh at the University of Oxford.
“We have evidence that poor adherence to antihypertensive medication is associated with worse outcomes,”explained Qianqian Yang, a PhD student at Oxford University and part of the research team.
“However, previous data has come from observational studies and could be confounded by other factors. We undertook an analysis of randomised trial data to assess the true impact of adherence on the benefits of antihypertensive treatment,” Yang continued.
In patients with higher adherence, systolic blood pressure was reduced by 5.2 mmHg in the intervention group versus the comparator group. In patients with lower adherence, the reduction was only 3 mmHg.
The team carried out a meta-analysis of 91,339 participants in nine clinical trials where an antihypertensive regimen (intervention group) was compared with either placebo or a less intensive regimen. Participants were divided into high and low level of adherence groups based on how much they look of their assigned treatment.
The significant findings came when Yang and the group moved onto assessing the impact adherence had on major cardiovascular disease.
The incidence of major cardiovascular disease, defined as stroke, myocardial infarction or ischaemic heart disease and heart failure causing death or hospitalisation, was cut by 11% in those with higher adherence. However, in those with lower adherence, there appeared to be no significant reduction, the researchers noted.
“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,” Yang commented.
Approximately 1.4 billion adults worldwide aged 30–79 years are estimated to have high blood pressure, which is one of the most significant risk factors for cardiovascular disease burden. There exists a plethora of hypertensive therapies, including ACE inhibitors, beta-blockers, angiotensin receptor blockers, calcium-channel blockers, and vasodilators, among others. Ramipril and lisinopril are among the top-selling prescription medicines.
Despite their high efficacy in reducing cardiovascular events, many patients do not take products as prescribed. This is fuelled by myriad factors, according to research published in the American Heart Association Journals’ Hypertension.
To combat poorer outcomes, the team at Oxford University say that adherence assessment and education should be promoted, alongside introducing strategies to improve sticking to treatment regimens. Single-pill combinations and longer-acting agents represent modality advancements that would mitigate the effects of occasionally missed doses.
