Treatment-Resistant Hypertension among Older Adults
Treatment-resistant hypertension (TRHTN) is a common challenge in geriatric practice and a significant cause of mortality and morbidity among older adults. In this overview, we will use a case-based approach to define the magnitude of the problem, identify characteristics of individuals with TRHTN, and explore the causes of uncontrolled hypertension including technical issues, patient-related and physician-related factors, and secondary causes of hypertension. We will then provide a simple approach to the problem, illustrating straightforward diagnostic workup and therapeutic options. In our approach most of the emphasis has been given to detailed history-taking and a targeted physical examination.
Key words: resistant hypertension, hyperaldosteronism, obstructive sleep apnea, older adults.
Case
You are following a 68-year-old man with a few years history of hypertension that has been resistant to significant doses of angiotensin converting enzyme inhibitor (ACEI), beta-blocker, and thiazide diuretic medications. He is also overweight (BMI of 31), and complains of restless sleep. He is otherwise healthy and does not smoke or drink alcohol. His systolic and diastolic blood pressures range from 156 to 170 mmHg and 92 to 96 mmHg, respectively, and his pulse rate is 63 beats per minute. His physical examination, including ocular fundi and cardiovascular examinations, is normal. His serum electrolytes and creatinine levels are within normal limits, with no microalbuminuria. His 2D echo showed only mild left ventricular (LV) hypertrophy with normal LV function. What would be the proper approach to this patient for further assessment and management?
Introduction
Arterial hypertension is a leading risk for morbidity and mortality in Canada1,2 as well as the most frequent reason for a visit to the physician’s office.3 Older adult populations have a higher prevalence of hypertension--over half of older Canadians have hypertension--and they are at greater risk for cardiovascular morbidity and mortality from it. However, they also have a greater reduction in cardiovascular risk with treatment than younger persons.2,3
Definition
Treatment-resistant hypertension (TRHTN) is defined by a blood pressure higher than 140/90 mmHg, or higher than 130/80 mmHg among persons with diabetes or renal disease (urinary protein excretion > 300 mg/day or serum creatinine level > 133 µmol/L), despite adherence to appropriate treatments with full doses of at least three antihypertensive medications, including a diuretic.4
Prevalence
Although the exact prevalence of TRHTN is unknown, it is likely that this condition will become increasingly common, driven by an aging population, obesity, nonadherence trends, and effects of target-organ disease.5 The estimated incidence of true TRHTN from the entire cohort of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT)4,8 is approximately 15% of the hypertensive population.9 However, observations suggest that blood-pressure goals may be difficult to achieve in as many as 40% of patients.6,7
Patient Characteristics
Treatment-resistant hypertension is associated with several characteristics that predispose patients to difficulty in achieving blood pressure (BP) goals. These features include obesity, diabetes, chronic kidney disease, and being of the black race or female sex. Rates of TRHTN are also higher among individuals with target-organ damage, including left ventricular hypertrophy and renal disease.10,11 Resistant or difficult-to-control systolic hypertension is more common among persons over the age of 60 years than among younger individuals.12