Do antihypertensive drugs do more harm than good in patients with mild hypertension?

I know that I can be prone to bouts of high blood pressure (hypertension) particularly when I see those pesky goblins careering round the woodland causing havoc – they certainly make my blood boil!  There are plenty of people out there though who have no idea they suffer from this condition and that ultimately their health and lives are at risk. The ‘silent killer’ can be hard to recognise and causes millions of deaths around the world each year.

Once diagnosed there are effective drug therapies that you can take to reduce your blood pressure and your risk of heart attacks, strokes and other serious conditions. These drugs are not without their side effects though and a new Cochrane review has suggested that many patients with hypertension are being over treated with no real benefit to their health.

Specifically, the study refers to patients with mild hypertension (systolic BP 140-159mmHg and/or diastolic BP 90-99mmHg). The individuals have no previous cardiovascular events and are referred to as ‘primary prevention’ cases. In the past research has mostly combined these patients with ‘secondary prevention’ patients i.e. those who have had a cardiovascular event and suffer moderate to severe elevations of blood pressure (>160/100 mmHG). Results were collated together and because treatment was shown to be beneficial in severe cases, assumptions were made that it benefited those with mild hypertension too.

The aim of the Cochrane review, therefore, was to investigate the effects of antihypertensive treatment drug therapy on mortality and morbidity in adults with mild hypertension and without cardiovascular disease. After a search of relevant databases they identified four randomised controlled trials (RCTs) with 8,912 participants. The outcomes assessed were mortality, stroke, coronary heart disease (CHD), total cardiovascular events (CVS) and withdrawals due to adverse effects. All the trials were of at least one year’s duration and this is what they found after meta-analysis:

  • Treatment for 4–5 years with antihypertensive drugs as compared to placebo did not reduce total mortality (RR 0.85, 95%CI 0.63, 1.15)
  • In 7,080 participants treatment with antihypertensive drugs as compared to placebo did not reduce CHD (RR 1.12, 95%CI 0.80, 1.57), stroke (RR 0.51, 95%CI 0.24, 1.08) or total CVS (RR 0.97, 95%CI 0.72, 1.32)
  • 9% of patients treated with drugs withdrew due to adverse effects (RR 4.80, 95%CI, 4.14, 5.57)

But:

  • The findings of the review were limited as they were not able to get individual patient data from all the trials with patients in this subgroup
  • The risk of bias assessment suggested a moderate to high risk of bias
  • There were a relatively low number of trials included in the analysis

The authors concluded:

“Based on the best available evidence at the present time, this review does not show any significant benefit of antihypertensive drug therapy in reducing mortality, heart attacks, strokes or overall cardiovascular events”.

“It is likely given this evidence many individuals with no cardiovascular disease and mild hypertension would choose non-drug treatments (diet, exercise, stress management etc) rather than drug therapy”.

It definitely seems to be the case that it cannot be assumed that the benefits outweigh the harms with regard to drug treatment for all those who suffer with hypertension. More research is clearly needed to understand fully the different needs of those suffering mild high blood pressure.

To ease my goblin induced hypertension I’m off in search of an alternative therapy. I’ve heard a whisper in the woodland that garlic is widely taken for its blood pressure lowering effects. Time to investigate this potentially whiffy solution.

Links:

Diao  D, Wright  JM, Cundiff  DK, Gueyffier  F. Pharmacotherapy for mild hypertension. Cochrane Database of Systematic Reviews  2012, Issue 8. Art. No.: CD006742. DOI: 10.1002/14651858.CD006742.pub2.

Cochrane summary of this review.

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Sarah Holloway

My name is Sarah Holloway. I am an Associate Lecturer with the Open University, teaching on the Understanding Health course. Before working for the OU I lectured in physiology and nutrition at The London Institute. I have a background in medical research and gained my biochemistry Ph.D whilst working at the Imperial College School of Medicine.

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