Analysis of Factors Relating to Day-to-Day Home Blood Pressure Variation in Hypertensive Patients

Abstract

Objective: In order to prevent cardiovascular events and organ injuries in hypertensive patients, strict blood pressure (BP) control over 24 hours is of primary importance. In addition to the BP level, it has been indicated that the variabilities of blood pressure during a day or between visits also influence the risk of cardiovascular disorders. This study aimed to delineate the factors relating to the variations of office and home BPs throughout a year in hypertensive outpatients under antihypertensive therapy. Design and method: The subjects enrolled in this study were 83 hypertensive out-patients who recorded home blood pressure measurements. Office BP and the home BP records within 7 days before each visit were collected for the analyses calculating the coefficient of variation (CV). In addition to the physical findings such as blood pressure and body mass index, laboratory data of blood and urine samples were collected. Results: The office BP value (131/77mmHg) was comparable to the morning home BP (130/76) and higher than the evening home BP (126/73), however, the CV values were comparable between the office and the morning and evening home BPs. Correlations of BP and CV were stronger between the morning and the evening home BPs than between the office and the home BPs. The CV of systolic office BP was greater in patients with diabetes mellitus than patients without diabetes (7.8 vs 6.1%). In patients with chronic kidney disease, the CVs of diastolic office BP and diastolic evening home BP were greater than patients without chronic kidney disease (8.0 vs 6.2% and 8.1 vs 6.7%, respectively). In addition, The CVs of diastolic morning and evening home BP were positively correlated with serum creatinine and negatively correlated with estimated glomerular filtration rate. Patients with cardiovascular diseases such as stroke and coronary artery disease showed greater CV of diastolic morning home BP than patients without cardiovascular diseases (8.2 vs 6.6%). Conclusions: These results suggest that the home BP exhibits different variability from the office BP and the BP variability is increased in high-risk hypertensive patients with diabetes mellitus, chronic kidney disease and cardiovascular diseases.