Blood Pressure

Click on table to enlarge. These figures help to put relative risk, absolute risk and percentage chance in perspective. 20% reduction sounds a lot. 96.8 % chance of surviving as opposed to a 96% chance doesn't sound like very much. 4S was a trial of statins on folk that had already had a CVD event ie secondary prevention. The WOSCOPS was a trial of statins for primary prevention in high risk patients. That BP result is interesting!! Click here to see where this came from.

while hypertension is an established risk factor for coronary heart disease at all ages and in both sexes, most high blood pressure-lowering trials have shown no reduction in coronary or total mortality in women and younger individuals (2) Uffe Ravnskov and in many studies, no effect has been demonstrated on male mortality either (3). This clearly indicates that hypertension is not a causa vera of coronary heart disease and "risk marker" would be a more appropriate description.

Here are three facts that currently co-exist in the world of medical research. Starting in the early nineteen eighties when the Medical Research Council (MRC) UK carried out the first ever long-term study into the effect of blood pressure lowering on mortality and morbidity. The drugs used were a diuretic and a beta-blocker.

Up to this point, you may be surprised to hear, this issue had never been studied. It was sort of assumed that a high blood pressure caused CHD, so if you lowered the blood pressure, you would prevent CHD.

The primary finding of the MRC trial was that blood pressure lowering had no impact on the rate of death from CHD. (There was some reduction in stroke and renal failure.)

Jumping to the present day, the ALLHAT study recently showed that there was no difference in CHD prevention between diuretics, beta-blockers, ACE-inhibitors and Calcium Channel blockers.

However, a recent meta-analysis in the NEJM shows that ACE inhibitors do provide protection against CHD.

From second article

From the European Heart Journal Issue 20, October 2000.

‘No randomized trial has ever demonstrated any reduction of the risk of either overall or cardiovascular death by reducing systolic blood pressure from our thresholds to below 140mmHg.’

‘Most importantly, the current paradigm considerably over-estimates the risk in the mid-range of pressure (roughly 125 — 180mmHg). .......... Consequently, a large proportion of the population considered at increased risk with the current cut-point are in fact at no increased risk.’

Developers of guidelines, ourselves included, have been overburdened by evidence which gives undue emphasis to the relative risks........ We think it is time to consider basing guidelines explicitly on clinically more useful absolute measures of the effects of treatment. Indeed, we suggest that the clinical credibility and success of the guidelines process depends on it.

Yup! Convince me, as a GP, that the benefits out weigh the harms - present it in a black and white manner. Be brutally straight forward about harms. What about harms that might take 20 years to show up!! Talk about these too! Present guidelines in ways that lay people can understand. I like percentage chance with and without intervention.

Find visual ways like this prostate risk roulette wheels