MEDIAN ANALYSIS OF BLOOD-PRESSURE FOR A SAMPLE INCLUDING TREATED HYPERTENSIVES

We consider the analysis of epidemiological studies in which the outco me of interest is a physiological disturbance (such as blood pressure) which may have been corrected by medical intervention (such as antihy pertensive treatment). It is important to take account of such interve ntion in studying the determinants of hypertension. We recommend using the median as a measure of location and assuming that the underlying values of subjects under intervention lie above the median. Some well- established exact methods for simple problems are presented. An exampl e is given in which the blood pressure differences between Afro-Caribb eans and Europeans are underestimated by about one-quarter if adjustme nt is not made for treated hypertensives.