Sex differences in ambulatory blood pressure monitoring.
OBJECTIVE
Referral to ambulatory blood pressure monitoring may have bearing upon blood pressure control and prognosis. We describe sex-related differences in referral for ambulatory monitoring and their prognostic impact.


METHODS
Between 1991 and 2005, 3957 patients were monitored in our ambulatory monitoring service, of whom 2114 (53%) were women. Demographic and clinical data were analyzed according to sex.


RESULTS
Age (58+/-15 vs 52+/-17 years, respectively) and body mass index (27.5+/-4.9 vs 26.9+/-4.0 kg/m(2), respectively) were higher in women than men. Treatment for hypertension was more prevalent in women (62% vs 53%, respectively). Clinic systolic blood pressure (148+/-24 vs 146+/-20 mm Hg, respectively) and clinic pulse pressure (65+/-22 vs 59+/-18 mm Hg, respectively) were higher in women compared with men. In women, the white-coat effect was increased, compared with men; 5.2+/-12.4% vs 1.5+/-10.7% systolic, and 5.4+/-11.2% vs 3.6+/-10.3% diastolic. Consequently, women had lower ambulatory blood pressure than men. In women, 24-hour blood pressure was 136+/-17/76+/-10 vs 140+/-15/81+/-10 mm Hg in men, awake blood pressure 141+/-17/80+/-11 vs 144+/-15/84+/-10 mm Hg, and sleep blood pressure was 125+/-19/67+/-10 vs 127+/-18/71+/-11 mm Hg. Age-adjusted ambulatory blood pressure also was lower in women. Ambulatory heart rate was higher in women (P <.0001). Kaplan-Meier survival did not differ by sex (P=.66), despite older age and higher clinic blood pressure.


CONCLUSIONS
The results might imply that referral was driven by the physicians' overall patient risk perception. The greater magnitude of white-coat effect in women, and correspondingly lower ambulatory blood pressure, might in part account for similar mortality in the face of older age and higher clinic blood pressure.
Ben-Dov
Iddo Z
IZ
Nephrology and Hypertension Services, Hadassah - Hebrew University Medical Center, Jerusalem, Israel. iddobe@ekmd.huji.ac.il
Mekler
Judith
J
Bursztyn
Michael
M
D000328:Adult; D000368:Aged; D001294:Attitude to Health; D018660:Blood Pressure Monitoring, Ambulatory / Q000523:psychology / Q000706:statistics & numerical data; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012017:Referral and Consultation / Q000706:statistics & numerical data*; D016387:Women's Health