Abstract P302: Prevalence of refractory hypertension in the United States from 1999-2014

Abstract

Background: Refractory hypertension has been defined as uncontrolled blood pressure (BP at or above 140/90 mmHg) when taking five or more classes of antihypertensive medication. Unbiased estimates of the prevalence of refractory hypertension in the United States are lacking. Methods: Refractory hypertension was assessed in the National Health and Nutrition Examination Survey. Eight cycles of NHANES surveys (1999-2014) representing 41,552 patients were included. Patients younger than 18 and who were pregnant were excluded. Prevalence of refractory hypertension was estimated in the hypertensive population (systolic BP ≥140 or diastolic BP ≥90 or taking an antihypertensive medication) after adjusting for the complex survey design and standardizing for age. Logistic regression was used to test for temporal trends and to compare prevalence across age classes (18-39, 40-59, 60+), genders, races, and chronic kidney disease status. Results: Refractory hypertension was found in 0.30% of all hypertensive individuals. Although prevalence of refractory hypertension peaked at 0.54% of hypertensive individuals in the 2005-2006 cycle, there was no significant trend in prevalence through time (p = 0.29). No individuals under 40 years old were observed with refractory hypertension, and refractory hypertension was more common in individuals 60 and older than in individuals 40-60 years old (odds ratio = 4.55, p = 0.004). There was no difference in the prevalence of refractory hypertension between males and females (p = 0.24), but white and black individuals were more likely to have refractory hypertension than individuals of Hispanic or other descent (OR = 4.63, p = 0.002). Finally, individuals with chronic kidney disease were significantly more likely to have refractory hypertension (OR = 9.88, p < 0.001). Conclusions: We provided the first nationally representative estimate of the prevalence of refractory hypertension in the U.S. Recently lowered BP targets, an aging population, and increased incidence of co-morbidities like chronic kidney disease all create the potential for increases in this hypertensive phenotype in the future.