Clinical Health Updates

BP and cholesterol are associated with vascular mortality

Clinical question
Are cholesterol and blood pressure associated with an increase in vascular mortality?

Bottom line
Total cholesterol was positively associated with IHD mortality in both middle and old age and at all blood pressure levels. The absence of an independent positive association of cholesterol with stroke mortality, especially at older ages or higher blood pressures, is unexplained, and invites further research. Nevertheless, there is conclusive evidence from randomised trials that statins substantially reduce not only coronary event rates but also total stroke rates in patients with a wide range of ages and blood pressures.
Reference
Prospective Studies Collaboration, Lewington S, Whitlock G, Clarke R, et al. Blood cholesterol and vascular mortality by age, sex, and blood pressure: a meta-analysis of individual data from 61 prospective studies with 55,000 vascular deaths. Lancet 2007;370(9602):1829-1839.

Study design: Meta-analysis (other)

Synopsis
These intrepid authors pooled data on nearly 900,000 individual patients enrolled in 61 prospective cohort studies. In these studies, approximately 55,000 patients died. Only 150,000 of the patients had lipid levels available, of whom approximately 5000 died. The authors evaluated the relationship between cholesterol level, blood pressure, age, and gender on vascular mortality (ischemic heart disease, stroke, and “other”). To reduce undue influence of a few outliers, they excluded patients with astronomical cholesterol readings. They don’t report how many patients dropped out of the studies or the number of deaths from all causes. They do, however, report MANY relationships. If you want all the data, get the paper. On the whole, the authors found that the higher the cholesterol level, the greater the risk of vascular death. They also report a nearly linear risk of vascular mortality that increases as the patient gets older, independent of gender. Blood pressure has a similar relationship and blood pressure and cholesterol have additive effects. In contrast with randomized trials that show statins may decrease stroke risk, lipids were weakly and inconsistently associated with stroke deaths. This reinforces the theory that statins may have beneficial effects independent of their effects on lipids.