According to the World Health Organization (WHO), hypertension or high blood pressure is common around the world, mainly because people are living longer and the prevalence of contributing factors such as obesity. For example, about one in three adults in the US has high blood pressure.
However, while the treatment of the condition has been shown to prevent cardiovascular diseases and to extend and enhance life, we don't seem to be managing high blood pressure as well as we could, says the WHO.
In this study, Dr Ramón Hermida and colleagues, all of the University of Vigo, found that patients who took at least one blood- pressure lowering medication at bedtime had better control of their blood pressure and were less likely to experience heart problems than counterparts who took their medications first thing in the morning.
The results suggest that with little extra effort and at no extra cost, patients could significantly reduce their risk of heart attack, stroke and other heart conditions.
Before this study we alread knew that the time of day when patients take their blood pressure meds affects blood pressure patterns, but little was known about the effect it might have on heart health.
So Hermida and colleagues set out to investigate this in a group of 661 patients with chronic kidney disease and high blood pressure.
They randomly assigned the patients to one of two groups. In one group the patients took all their prescribed hypertension medications first thing in the morning and in the other group they took at least one of them at bedtime.
They measured the patients' blood pressure (by asking them to wear an ambulatory monitor for 48 hours) at the start of the study, and also 3 months after any change in treatment, or at the least, every year.
After a median follow up of 5.4 years, the researchers found that:
- Patients who took at least one blood-pressure lowering medication at bedtime had an adjusted risk for total cardiovascular events that was a significant two thirds lower than that of the patients who took all their meds when they woke up in the morning (adjusted hazard ratio HR 0.31; 95% confidence interval CI ranging from 0.21 to 0.46; P < 0.001). The total cardiovascular events included angina, myocardial infarction (heart attack), death, revascularization, heart failure, blocked artery in lower limbs, blocked retinal artery and stroke.
- There was a similar significant reduction in risk for bedtime dosing for a composite of three events: cardiovascular death, myocardial infarction, and stroke (adjusted HR 0.28 with 95% CI 0.13 to 0.61and P < 0.001).
- Also, the patients who took at least one med at bedtime had a significantly lower average sleep-time blood pressure and more of them showed better control of ambulatory blood pressure (56% vs 45%, P = 0.003).
- Each 5 mm drop in mercury level of mean sleep-time systolic blood pressure was linked to a 14% reduction in risk for for cardiovascular events over the follow-up period (P < 0.001).
"Our results indicate that cardiovascular event rates in patients with hypertension can be reduced by more than 50% with a zero-cost strategy of administering blood pressure-lowering medications at bedtime rather than in the morning," adding that:
"This study also documents for the first time that sleep-time blood pressure is the most relevant independent marker of cardiovascular risk."
Written by Catharine Paddock PhD