John: Hello, I'm John Hilton, editor of the Cochrane Editorial unit. Several drugs have been shown to lower blood pressure in people with hypertension, but it‘s important to know the size of the benefit separately for young healthy adults aged up to 59 years and for those who are 60 or more. A Cochrane Review for the older age group has been available for some time, and Vijaya Musini from the University of British Columbia in Vancouver, Canada and colleagues in the Cochrane Hypertension Group published the first Cochrane Review for the younger age group in August 2017. Here’s Vijaya to tell us more.

Vijaya: High blood pressure or hypertension is a chronic condition associated with an increased risk of death and health problems such as heart disease, stroke and kidney disease. For patients with established moderate to severe hypertension, blood pressure should first be managed with life-style and behaviour modification. But, if these measures prove inadequate, then the patient might need to move on to pharmacotherapy.
Systematic reviews have shown benefits of antihypertensive drug therapy in reducing cardiovascular morbidity and mortality but most of the evidence is in people 60 years of age and older. We wanted to focus on the effects in younger adults, who were aged 18 to 59 years with mild to moderate primary hypertension.
We included seven randomized studies with more than 17,000 participants in total, who had been followed for an average of 5 years. The treatments in most of the studies were high dose thiazide diuretics or beta-blockers, and the effects on blood pressure varied so much between the studies that we are uncertain as to the size of the blood pressure lowering effect.
Overall, there is low quality evidence that antihypertensive drug therapy may have little or no effect on all-cause mortality or coronary heart disease, when compared to placebo or a control group receiving no tablets. But, it might reduce total cardiovascular mortality and morbidity from 4.1% to 3.2% over five years, due to a reduction in strokes
Therefore, our new review shows that antihypertensive drugs used to treat predominantly healthy adults aged 18 to 59 years with mild to moderate primary hypertension led to a small absolute decrease in cardiovascular mortality and morbidity, primarily due to a reduction in stroke mortality and morbidity. All-cause mortality and coronary heart disease were not reduced, and there is a lack of good evidence on withdrawal due to adverse events. More trials are needed to help us to understand the effects of these drugs in this age group. These trials should last at least 10 years and should compare different first-line drug classes and strategies.

John: Thanks Vijaya. If you’d like to read the full findings of the Cochrane Review and to watch for updates should the additional trials get done, just go online to Cochrane Library dot com and search 'pharmacotherapy and hypertension'.