Masked Hypertension in Low‐Income South African Adults

Abstract

4While South Africa has one of the highest hypertension rates globally, there are few data on masked hypertension (MHT) and white-coat hypertension (WCHT). This study measured the frequency of MHT and WCHT in low-income (<$500 US per month) South African adults, evaluating cardiovascular risk by arterial stiffness. Participants (n=101, 50% male; mean age 39.4AE9.7 years) were recruited from a large North-West Province employer. Clinic and 24-hour blood pressure (BP) and pulse wave analysis were recorded. Clinic BP identified 18% of patients as hypertensive, while 24-hour BP showed that 63% of patients were hypertensive. The frequency of MHT was high (33 of 81, 41%) with only one case of WCHT. In comparison to those with normal clinic and 24-hour BP, augmentation index and pulse wave velocity were significantly higher in those with hypertensive 24-hour BP irrespective of clinic BP, indicating that, in this group, masked and sustained hypertension carry a similar elevated cardiovascular risk.

Ambulatory blood pressure and arterial stiffness web‐based telemonitoring in patients at cardiovascular risk. First results of the VASOTENS (Vascular health ASsessment Of The hypertENSive patients) Registry

“…Also, hypertension played an important role in the determination of arterial stiffness and central BP in our population. After proper adjustment for confounding factors, both peripheral and central BPs, PWV and AIx were increased in patients with a known history of hypertension, confirming previous findings obtained in hypertensive patients studied either at rest or in ambulatory conditions …”

Prevalence and Determinants of Masked Hypertension Among Black Nigerians Compared With a Reference Population

“…Most, [3][4][5][6] although not all, 7,8 cross-sectional data from different areas of sub-Saharan Africa [3][4][5][6] aimed at evaluating the burden of high blood pressure (BP) defined hypertension solely on the basis of clinic BP. This excludes a substantial number of individuals who have hypertension that is masked to conventional office measurement.…”

Revealing Masked Hypertension in People of African Ancestry: We Need to Do Better

“…The authors noted that the adjusted augmentation index was higher in the MHT and HT groups compared with the NT group, especially during the night period ( P =.009). In addition, PWV adjusted for mean arterial pressure and age was also significantly higher in the MHT and HT groups than in the NT group ( P <.001) …”

“…In this issue of the Journal of Clinical Hypertension , Ware and colleagues, in a cross‐sectional study, seek to determine the frequency of masked HT (MHT) and white‐coat hypertension (WCHT) in 101 South African adults (50% male; 96% black, 4% mixed race) employed in low‐income occupations. The term MHT was first coined by Pickering and his coworkers in 2002 to describe nonelevated BP in usual clinic settings that occurs alongside elevated average ambulatory BP (ABP), hiding the recognition of HT.…”

“…While individuals with MHT and HT share several common risk factors (age, male sex, increased body mass index), factors outside of the usual clinic setting such as physical inactivity, smoking, alcohol use, and psychological stress may play an important role in both populations. Since patients with MHT may have lower anxiety when evaluated in the clinic setting as compared with patients with WCHT, high occupational stress and low levels of autonomy combined with a high workload (job strain) and effort‐reward imbalance (high effort and low reward) may be important factors underlying increased levels of MHT . Therefore, high levels of stress and depression may contribute to disparate levels of MHT in disadvantaged populations, including blacks in the United States and South Africa.…”