Hematocrit, blood pressure, and hypertension. The Gubbio Population Study.

Abstract

Baseline data from the Gubbio Population Study in north central Italy were used to investigate the relation of hematocrit to blood pressure and hypertension among 2,809 men and women aged 25-74 years. Independent of gender, age, and other confounders, the hypertensive group had a higher hematocrit than the nonhypertensive group (p<0.001). In comparison with the untreated hypertensive group, the hypertensive group being treated with diuretics or with other drugs only had similar mean hematocrit levels despite significantly lower blood pressures. Hematocrit was positively correlated with systolic pressure (r=0.085,p<0.01 andr=0.264,p<0.001 for men and women, respectively) and diastolic pressure (r=0.214, p<0.001 and r=0.266, p<0.001). In both sexes, whether or not the treated hypertensive group was included, age-adjusted prevalence of hypertension and average blood pressure were higher for persons in higher qulntiles of hematocrit (/><0.001). The association of hematocrit with blood pressure and hypertension was significant and independent of several confounders. The regression coefficient of blood pressure on hematocrit ranged between 0.410 and 0.620 mm Hg per unit of hematocrit for systolic pressure and between 0371 and 0.581 for diastolic pressure, depending on gender and whether the treated hypertensive group was included in multiple regression analysis. Based on exponentiation of the multiple logistic coefficient, prevalence of hypertension was at least two times greater for persons whose hematocrit levels were higher by 10 units. (Hypertension 1992^20-319-326) KEY WORDS • hematocrit • blood pressure • hypertension, essential • Gubbio population study H ematocrit is the most important determinant of whole blood viscosity. 1 Blood viscosity and vascular resistance affect total peripheral resistance to blood flow, 2 which is abnormally high in the established phase of primary hypertension.3 It has been reported that hematocrit is increased or normal in human hypertension*-9 and increased in rat genetic hypertension. 8 -10 In genetically hypertensive rats, it has also been shown that reduction of hematocrit with maintenance of blood volume reduces blood pressure.11 -13 Correspondingly, clinical studies have reported that increase of hematocrit is followed by increase in blood pressure and possibly onset of hypertension in anemic patients.14 - 20From the Division of Nephrology, First Medical School (M.C), University of Naples "Federico II," Naples; the Center for Epi Many clinical and experimental studies have been done on the relation between hematocrit and blood pressure, but the epidemiological literature does not identify hematocrit as an important independent correlate of blood pressure in general populations. The present study of men and women from the Gubbio Population Study in north central Italy 21 shows that a significant positive association exists between hematocrit and blood pressure or hypertension, independent of other factors related to these end points. MethodsIn the Gubbio Study, the target pop...

Comparison of hematological parameters in primary hypertensives and normotensives of Sangareddy

“…These findings are similar to the earlier findings by Giacomo et al [7], Massimo et al [8], Dan et al [9] and Al-Muhana et al [10].…”

“…Alternative possibilities are that hematocrit contributes to the regulation of blood pressure or that some other factors are responsible for parallel changes of hematocrit and blood pressure. The role of other (possibly dietary) factors not considered in the present study cannot be excluded [8].…”

“…In patients with different forms of anemia, a significant increase of total peripheral resistance and arterial pressure and at times development of hypertension may occur when low hematocrit is increased by transfusion of packed red blood cells or by erythropoietin administration. Results of the previous studies indicate that a 10-unit increase in hematocrit (e.g., from 35% to 45%) would be associated with an increase of 4-6 mm Hg in arterial pressure and with a twofold increased risk of hypertension [8].…”

Hematocrit and Risk for Hypertension in Middle-Aged Japanese Male Office Workers.

“…Previous investigations into the effects of hematocrit on blood pressure have variously found that it is either related [1][2][3][4][5] or unrelated 6,7) to hypertension. These inconclusive results may have been resulted in part from ethnic or lifestyle differences in the study populations but also may have been strongly influenced by different methods used to investigate the association between hematocrit and hypertension.…”

Association between Hemoglobin Level and Endothelial Function in Uncomplicated, Untreated Hypertensive Patients

“…However, population-based studies have consistently demonstrated that, on average, [Hb] is raised in patients with essential hypertension (13). Thus, it appears plausible that Hb-dependent mechanisms influencing NO bioavailability contribute to endothelial dysfunction in hypertension.…”