Diurnal rhythm of blood pressure in patients with polycythemia vera.

Abstract

Polycythemia vera increases the risk of hypertension, but there is limited information about the effect on daily blood pressure fluctuations. This study aimed to demonstrate how diurnal blood pressure rhythm is affected in polycythemia vera patients. Fifty (50) patients (33 men; mean age 48 ± 15 years) with a diagnosis of polycythemia vera and 51 age and sex-matched healthy subjects for the control group were prospectively evaluated. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were evaluated by ambulatory blood pressure monitoring (ABPM) as average 24-hour, daytime and nighttime measures. Average 24-hour SBP and DBP, daytime SBP and DBP were similar in both groups. However, nighttime SBP and DBP were significantly higher in the polycythemia vera group compared with the control group (125.3 ± 17.2 and 73.7 ± 12.2 vs. 118.9 ± 12.2 and 69.5 ± 8.5; P = 0.034 and P = 0.044). Both nocturnal SBP fall and nocturnal DBP fall were blunted in the polycythemia vera group compared with the control group (-6.9 ± 8.9 and -11.3 ± 12.2 vs. -11.6 ± 7.7 and -16.3 ± 12.0, respectively). Both hemoglobin and hematocrit levels were positively correlated with nocturnal SBP fall (r = 0.306, P = 0.002 and r = 0.355, P < 0.001; respectively) in all patients. We found that the polycythemia vera group had significantly decreased nocturnal dipping compared with healthy controls. The SBP fall was also positively correlated with hemoglobin and hematocrit levels.