High blood pressure is common, and is associated with early death, stroke and heart disease. In deciding how to manage it, one the first questions is which drug to use. A new Cochrane review provides knowledge to answer this by reviewing the evidence on six different classes of drugs and presenting the findings in a standardised way.
The authors of the review use evidence from randomised trials comparing drug treatment with a placebo of no treatment. The trials needed to have lasted at least one year. A total of 24 trials were judged to be eligible, out of 57 studies assessed in detail which, themselves, came from a check of over 6000 journal articles. The included trials had studied nearly 60,000 people.
Three quarters of the trials looked at thiazides. During the follow-up of the 40,000 patients in these studies, there were significantly fewer deaths and strokes among those allocated a thiazide. The drug also led to less cardiovascular disease, and lower doses were found to be as good, if not better, than higher doses. Benefits on the same outcomes were found for ACE inhibitors, although with a much smaller amount of randomised evidence. Beta-blockers and calcium channel blockers were found to reduce the risk of stroke, but not death. The effects of the other two major classes of drug, alpha-blockers and angiotension II receptor blockers could not be studied in the review because of a lack of eligible trials.
Having amassed and carefully appraised all this evidence, the authors of the new Cochrane review conclude that low-dose thiazides are more effective as initial treatment for hypertension than high dose thiazides or first-line beta-blockers. They note that first-line ACE inhibitors are similar to low-dose thiazides, but more expensive.
In summary, they recommend that the first choice class of drug for most patients with high blood pressure should be low-dose thiazides, adding that these are also very inexpensive.
This Cochrane review is available in full at www.mrw.interscience.wiley.com/cochrane/clsysrev/articles/CD001841/frame.html
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August 24 2009