Abstract 18611: Masked Hypertension in Prehypertensive African Americans After Dietary Stabilization
Objective: Office blood pressure (BP) measurements miss a significant number of individuals with masked hypertension (MHT). The aim of our study was to identify the prevalence of MHT and compare plasma levels of inflammatory biomarkers in apparently healthy prehypertensive (Office BP 120–139/80–89 mmHg) African Americans after a structured 6 wk dietary stabilization period.
Methods: 50 African Americans (10M,40F; 52±6 yrs) who were sedentary, non-diabetic, non-smoking, devoid of cardiovascular (CV) disease and not on antihypertensive medication, followed a AHA low salt, low fat diet for 6 wks under the supervision of a registered dietician. Office BP was measured according to JNC 7 to identify prehypertension, n=41. Upon completion of the dietary stabilization, subjects underwent 24-hr ambulatory blood pressure monitoring (ABPM). Fasting blood samples were assayed for white blood cell count (WBC count), tumor necrosis factor-alpha (TNF-α) and high sensitivity C-reactive protein (hs-CRP).
Results: Subjects with true prehypertension (Office BP <140/90 mmHg and ABPM daytime BP <135/85 mmHg or nighttime BP <120/70 mmHg, n=17) and MHT (Office BP <140/90 mmHg and ABPM daytime BP ≥135/85 mmHg or nighttime BP ≥120/70 mmHg, n=24) were similar in age, BMI, lipid profile and blood glucose. No significant differences were found between true prehyprertensives and MHT for WBC count (6.7±0.4 vs 7.2±0.3 103/mL; p>.05) or TNF-α (35.6±18.6 vs 31.5±19.4 pg/mL; p>0.05). MHT had a significantly higher hs-CRP (3.9±3.1 vs 2.4±2.1 mg/L; p<0.05) compared to true prehypertensives.
Conclusions: After dietary stabilization, we identified MHT in ∼58% of prehypertensive African Americans and they exhibited higher levels of hs-CRP compared to true prehypertensives. These results suggest that a masking phenomenon may exist in prehypertensive African Americans with subclinical heightened vascular inflammation that is outside the influence of dietary habits. This highlights the need for out-of-office BP measurements through ABPM to accurately identify African Americans who are at greater CV risk despite BP levels below the hypertensive range and may suggest that office BP provides a potentially misleading assessment of the severity of hypertension in African Americans.
- © 2010 by American Heart Association, Inc.