High blood pressure is the worlds leading cause of premature death, with an estimated one billion individuals having high blood pressure.
In 2015, high blood pressure accounted for near ten million deaths, of which 3.5 million were due to stroke.
Nocturnal blood pressure has already been proven to better predict cardiovascular outcomes than daytime blood pressure.
The Hygia study proposed evidence that antihypertensive drugs that were taken in the evening rather than the morning reduced night-time blood pressure to a greater extent.
However, this study has attracted some criticism.
A new study, involving a pragmatic randomised trial in just over 21,000 patients with high blood pressure, hopes to answer whether timings of antihypertensive medications can have any benefits.
The patients were monitored over a five year period.
This trial, known as ‘TIME’, aims to test whether evening dosing of antihypertensive medication improved major cardiovascular outcomes compared to morning dosing.
The trial was advertised to adults who take at least one antihypertensive medication, once participants had successfully registered, they were randomised 1:1 to take their usual antihypertensive medication either in the morning or at night.
The composite primary endpoint was hospitalisation for nonfatal myocardial infarction or nonfatal stroke, or vascular death.
“Information on hospitalisations and deaths was obtained from participants by email and through record linkage to national databases and further data was gathered from family doctors and hospitals and independently adjudicated by a committee blinded to allocated dosing time.”
The study sample included 21,104 patients who were randomised, 10,503 took their dose in the evening and 10,601 to morning dosing.
The average age of participants was 65-years-old, 58 per cent were men and 98 per cent of the study were white.
The median of the follow up duration was 5.2 years, however, some participants were monitored for over nine years.
The primary endpoint occurred in 3.4 per cent of participants who were in the evening dosing group (0.69 events per 100 patient years), whilst it occurred in 3.7 per cent in the morning dosing group (0.72 events per 100 patient years.)
This gives an unadjusted hazard ratio of 0.95.
The results did not vary in pre-specified subgroup analyses, furthermore, taking medication in the evening was not harmful.
Principal investigator of the study, professor Thomas MacDonald says: “TIME was one of the largest cardiovascular studies ever conducted and provides a definitive answer on the question of whether blood pressure lowering medications should be taken in the morning or evening.
“The trial clearly found that heart attack, stroke and vascular death occurred to a similar degree regardless of the time of administration.
“People with high blood pressure should take their regular antihypertensive medications at a time of day that is convenient for them and minimises any undesirable effects.”
