Abstract 5154: Isolated Nocturnal Hypertension is Associated With Pre-clinical Vascular Pathology in People of African Descent
Recent large clinical studies indicate that an inability to decrease blood pressure (BP) at night is associated with excessive cardiovascular morbidity and mortality. In a randomly selected population sample of subjects (40% hypertensive, 60% overweight and obese, and 8% diabetic), in whom 458 had high quality 24-hour ambulatory BP monitoring and target organ assessments, we determined whether isolated nocturnal hypertension was associated with renal and vascular target organ changes. Pre-clinical renal target organ changes were assessed from urinary microalbumin-to-creatinine ratios (ACR) determined from 24-hour urine samples, and pre-clinical vascular pathology was assessed from carotid-femoral pulse wave velocity (PWV) determined using applanation tonometry. software. In the study sample 7.6% of participants had isolated nocturnal hypertension. Compared to the normomotensives, the isolated nocturnal hypertensives had a higher BMI (31 versus 27). In multivariate regression analysis adjusting for multiple confounders, participants with increased 24-hour BP values had a greater PWV (p<0.0001) and an increased urinary ACR (p<0.0001) as compared to participants with a normal 24-hour, day and night BP. Similarly, participants with isolated nocturnal hypertension, had an increased PWV as compared to participants with a normal 24-hour, day and night BP (p<0.0005). However, participants with isolated nocturnal hypertension had similar urinary ACR values as compared to participants with a normal 24-hour, day and night BP (p=0.62). There was also a strong relationship between nocturnal hypertension and both diabetes (p<0.017) and waist to hip ratio (p<0.038). Isolated nocturnal hypertension is associated with waist to hip ratio, diabetes and pre-clinical vascular but not renal target organ changes in a population sample of African ancestry. As pre-clinical vascular pathology, diabetes and increased waist to hip ratio are independent predictors of cardiovascular outcomes, these data suggest that outcome studies are required to determine whether isolated nocturnal hypertension is a clinical entity that requires therapeutic intervention and lifestyle changes.