Change Viewed on the Level

Readers of the Journal will have seen two contributions on the question of whether change in blood pressure is related to coronary heart disease, independent of the level of blood pressure.'' An analysis of data collected in the Seven Countries study led Farchi et al. to suggest that change of blood pressure is a predictor of heart disease independent of blood pressure level. Woodbury et al. reported a similar finding based on data collected in the Framingham Heart study. However, in a recently published report also using Framingham data, we found no evidence for an independent contribution of blood pressure change in predicting the risk of coronary heart disease, all cardiovascular diseases, and total mortality. It is the purpose of this article to discuss the reasons for these contrasting inferences, even arising from the same study. But first we have to make sure that the matter is worth talking about.