African Americans (AAs) have a high prevalence of hypertension and suffer a disproportionately high risk for cardiovascular disease compared to whites. Apparent treatment-resistant hypertension (aTRH) is a severe form of hypertension defined as requiring ? 4 antihypertensive medications to achieve blood pressure (BP) control. An estimated 9 million US adults have aTRH. Given the rigorous clinical work-up needed to rule out pseudoresistance and therefore, diagnose true TRH, the population prevalence of TRH is not known. We propose an ancillary study to the Jackson Heart Study (JHS), a large prospective cohort of AA adults (n=5,306) that will deeply phenotype participants with aTRH, ruling out pseudoresistance (i.e., inaccurate clinic BP measurement, presence of a white coat effect, suboptimal antihypertensive therapy, and poor medication adherence) and secondary causes of hypertension (i.e., primary aldosteronism, obstructive sleep apnea, and kidney disease). The JHS provides a highly feasible setting for the proposed study as it includes a large population of AAs with a high prevalence of hypertension and extensive data collection as part of an upcoming fourth parent study visit, which will facilitate the screening and recruitment of participants for our ancillary study. Based on data collected during the fourth JHS exam, we will identify 400 cases with aTRH and 200 treatment-responsive controls. These participants will undergo a clinical evaluation for TRH including ambulatory BP monitoring (ABPM) to detect white coat effect and urinalysis of antihypertensive drug metabolites to assess medication adherence. We will compare secondary causes of hypertension among aTRH cases and treatment-responsive controls. We will screen for primary aldosteronism and kidney disease using blood and urine samples and obstructive sleep apnea using home polysomnography. Finally, we will compare lifestyle factors for participants with true TRH compared to controls. We will assess dietary sodium by urinalysis, alcohol and non-steroidal anti-inflammatory drug use through questionnaires, and physical activity through actigraphy. The proposed study will help identify adults who may benefit from targeted therapies and lifestyle changes to improve health outcomes while avoiding unnecessary clinic visits and wasted healthcare resources caused by over-treatment among those with aTRH versus true TRH.
Through the proposed study, we hope to understand how many African Americans have a particularly severe form of high blood pressure called treatment-resistant hypertension (TRH). In order to do that, we need to rule out other conditions that are not TRH, but make a person's blood pressure high, such as not taking medications as prescribed, kidney problems, or disordered breathing while sleeping. Finally, we want to identify the role of lifestyle factors, such as diet and exercise, on this severe form of high blood pressure.
