DESCRIPTION OF A NEW QUOTIENT THAT MAY DIFFERENTIATE BLOOD-PRESSURE PROFILES IN ESSENTIAL VERSUS CUSHINGS SYNDROME-RELATED HYPERTENSION

Since the presence or absence of a nocturnal decrease in blood pressur e values (BP) may suggest an increased risk of visceral complications or the existence of secondary hypertension, several methods have been described for evaluating the BP profile. Nevertheless, a universally a ccepted system to evaluate this item has not yet been established. Our aim in this study was to test different dispersion quotients (DQ) whi ch estimate the differences between the mean of each hour, and the mea n of all the readings in the 24 h period. These quotients may be emplo yed regarding systolic (SEP) or diastolic (DBP) blood pressure, and ma y be referred to the whole period of 24 h, or to the subperiods mornin g (m), afternoon (a) or night (n). We have studied two non selected gr oups of essential (n=20) or secondary (Gushing's syndrome, n=17) hyper tensives. We observed a marked decrease in these quotients, particular ly DQ-SBP and NDQ-SBP, in secondary hypertensives (respectively 10.2+/ -2.9 vs 15.6+/-4.2 and 11.8+/-5.0 vs 20.5+/-6.3, p<0.0001), thus indic ating, a blunted nocturnal fall of BP in these patients. Also the DQ a nd particularly DQ-SBP, nDQ-SBP and nDQ-DBP, showed a high positive an d negative predictive value, sensitivity and specificity for pertainin g to the Gushing's syndrome group (respectively: 0.75, 0.88, 0.88, 0.7 5; 0.86, 0.82, 0.77 0,90; and 0.78, 0.84, 0.82, 0.80).