Need for a revamp of hypertension treatment
May 25, 2009 - 2:11:40 AM
In the British Medical Journal May 23rd 2009 issue, the findings of a meta-analysis by Law and Colleagues has been published. The chief findings are that ß blockers are as effective as other blood pressure medication. Also, they found that regardless of the pre-treatment blood pressure, there was a reduction in cardiovascular risk in patients treated with anti-hypertensive medication who had a reduction in systolic or diastolic blood pressure.
The meta-analysis included 147 trial reports. In the trials that compared ß blockers in individuals with a history of coronary heart disease(CHD), with placebo or untreated control group, CHD was reduced by 29%. This was significantly different from groups on ß blockers without a history of CHD, or even those on other anti-hypertensive medication with or without a history of coronary heart disease, where the reduction was 15%. A 31% risk reduction was observed with the use of ß blockers in patients recruited immediately after a myocardial infarction, with only a 13% risk reduction in CHD when ß blockers were used in other circumstances.
The meta-analysis showed that using any of the five main categories of blood pressure medications (thiazides, ß blockers, Calcium Channel Blockers (CCBs), Angiotensin Converting Enzyme(ACE) inhibitors and Angiotensin Receptor Blockers(ARBs) ) to reduce the systolic blood pressure by 10 mmHg or the diastolic blood pressure by 5 mm Hg , resulted in a 22% reduction in CHD events and a 41% reduction in stroke.
Calcium channel blockers were found to reduce the risk of stoke by 33% compared to the overall reduction of 27% by all groups of anti-hypertensive medication.
The authors have also suggested that using three drugs at half standard dose would produce a greater reduction in risk of CHD and stroke than one drug at standard dose. This is an estimate and would need trials to further validate this.
Their finding that there was a reduction in risk for a specified change in blood pressure, independent of a person’s baseline blood pressure, would now cause us to wonder about blood pressure targets and their validity. “Lower the better” seems the way forward as suggested by the authors. The choice of anti-hypertensive drugs is also less important, except in acute myocardial infarction where ß Blockers have shown to be superior and in stroke where CCBs are preferred. Certain populations have not been specifically looked at in this meta-analysis and one would continue to choose ACE inhibitors and ARBs to treat end stage renal failure patients to protect residual renal function till further studies suggest otherwise. The choice of medication in the general population, therefore, would be determined by the side effects of the medication and that of the lowest blood pressure an individual can tolerate safely. Obviously, this is going to be a point of discussion for sometime to come.
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