[The association of hematocrit with blood pressure and left ventricular mass in subjects over 55]

To establish the association between hematocrit, blood pressure (BP), and left ventricular mass (LVM) in persons older than 55 years.

One hundred patients older than 55 years (46 males and 54 females) with a wide range in BP were studied on an ambulatory basis. The following parameters were determined: hematocrit, casual BP (CBP), 24-h ambulatory blood pressure monitoring (ABPM), left ventricular mass index (LVMI) determined by echocardiography (according to the Devereux's formula), cardiac output (CO) (determined by cardiac echocardiography), peripheral vascular resistances (PVR) (determined according to mean blood pressure and cardiac output), and levels of creatinine in plasma and sodium in 24-hour urine.

Mean age of patients was 65 years (range 55 to 83 years). Twenty-two percent of patients were smokers (17 males and 5 females) with a mean of 13 +/- 6 cigarettes/day. Mean hematocrit value was 41.4 +/- 3.6% (43.3 +/- 3.5 for males and 39.7 +/- 2.7% for females) (p < 0.001). Thirty-five percent of males and 26% of females had mild-moderate hypertension with an hematocrit of 42.3 +/- 3.5% versus 40.8 +/- 3.6% (p < 0.05). The LVMI was 132 +/- 37 g/m2 (139 +/- 38 g/m2 for males and 127 +/- 36 g/m2 for females). A significant linear association was observed between hematocrit value and diastolic BP: casual (r = 0.25; p < 0.05, 24 h mean (r = 0.34; p < 0.001), mean from 7 to 23 hours (r = 0.32; p < 0.001), mean from 23 to 7 hours (r = 0.37; p < 0.001). For females, these relationships were: r = 0.41, 0.36; 0.34 and 0.41, respectively (p < 0.01). No significant association was observed between these parameters among males. Among hypertensive patients this association was observed 24-h mean diastolic BP and mean from 23 and 7 hours (r = 0.39; p < 0.05). Among normotensive patients the values for this association were: r = 0.25; p < 0.05 and r = 0.26; p < 0.05, respectively. No significant association was observed between hematocrit value and LVMI for the total group and for the established subgroups.

Among patients older than 55 years a weak significant association was found between hematocrit value and diastolic BP (both casual and in that obtained with ambulatory monitoring), but not with the left ventricular mass. The mean hematocrit value was significantly higher for hypertensive than for normotensive patients.