The data here gives a fairly good idea of the bounds of the possible and plausible when lowering blood pressure and blood cholesterol, putting some numbers to the degree to which stroke risk can be reduced. Strokes occur due to breakage or blockage of blood vessels, and the roots of that lie in (a) the stiffening of blood vessels that breaks the feedback mechanisms determining blood pressure, and (b) the processes of atherosclerosis that produce fatty plaques in blood vessel walls, narrowing and weakening them.
Blood pressure medications don't address the roots of the problem, but force a lower blood pressure, which reduces the risk of rupture in weakened vessels. Lowered blood cholesterol, such as via statins, or more modern and effective approaches such as PCSK9 inhibition, reduces the pace at which atherosclerosis progresses over time by reducing the amount of damaged cholesterol in the blood stream. Again, it achieves this result not by addressing the root causes of that damage, but through a blanket lowering that happens to include the problem cholesterol molecules that feed the growth of atherosclerotic plaques. Fortunately it appears that we humans don't need anywhere as much cholesterol as we have; it is interesting to speculate on why we seem to have at least ten times as much in our bloodstreams as we need to get by.
Combining medication that lowers blood pressure with medication that lowers cholesterol reduced first-time strokes by 44 percent. Seventy-five percent of strokes are first-time strokes. High blood pressure and high cholesterol both increase the risk for stroke, the fifth leading cause of death in America. Yet it's not known whether combining drugs that lower blood pressure and cholesterol levels can protect individuals from stroke. Now, a study involving 12,705 participants from 21 countries shows that individually, drugs that lower blood pressure or cholesterol do indeed reduce stroke risk, but when combined, they offer even greater protection.
Taking daily doses of two blood pressure drugs (fixed dose candesartan and hydrochlorothiazide) along with a cholesterol-lowering drug (low-dose rosuvastatin), proved to be the most effective, cutting first-time strokes by 44 percent among patients at intermediate risk for heart disease. For those with very high blood pressure - readings 143.5 mm Hg or higher - taking 16 milligrams of candesartan plus 12.5 milligrams of hydrochlorothiazide every day reduced stroke by 42 percent. Compared with a placebo, stroke was reduced by 30 percent among participants taking daily doses of 10 milligrams of rosuvastatin.
The findings come from the Heart Outcomes Prevention Evaluation Study, a large, international study focused on heart disease and stroke prevention. The average age of the participants was 66 years; 46 percent were women, and 166 strokes occurred during an average follow-up of 5.6 years. At the start of the study, the average blood pressure was 138/82 mm Hg. A normal blood pressure reading is around 120/80 mm Hg. Based on these findings, researchers are now looking at developing a single pill that produces the same effects as taking multiple pills that lower both blood pressure and cholesterol.