Expert examines contribution of aldosterone in obesity-related hypertension
BOSTON — At the Cardiometabolic Health Congress, Colleen M. Majewski, MD, discussed the link between elevated aldosterone and obesity-related hypertension, and how knowledge of this association factors into the management of patients.
“We know that there is a link between hypertension and obesity, and there appears to be a link between hypertension [and obesity] and higher levels of aldosterone. And, generally, all components of the renin-angiotensin system appear to be up-regulated when patients have obesity. So, how does this factor into our management of patients?” Majewski, from the endocrinology, diabetes and metabolism section at University of Chicago Medicine, said.
Colleen M. Majewski
Data demonstrate links
Multiple data sets have demonstrated that the prevalence of hypertension and obesity are increasing in the United States. Other research, such as a cross-sectional study conducted in Switzerland and published in 2002, established correlations between systolic and diastolic BP with both waist circumference and waist-to-hip ratio. Further, it is estimated that at least 75% of the prevalence of hypertension is directly related to obesity, according to Majewski.
An increasing amount of data indicate that adipocytes may be producing substances that impact the renin-angiotensin-aldosterone system, leading to increased aldosterone levels and hormonal changes, she said.
A study that assessed aldosterone plasma concentrations in approximately 300 patients indicated significantly increased aldosterone levels among patients with a BMI greater than 35. The patients in the study were otherwise healthy and were not receiving any medications that would interfere with the renin-angiotensin-aldosterone system, Majewski added. In a separate study of 100 morbidly obese patients who underwent gastric bypass, aldosterone levels decreased along with mean BMI at the 36-month follow-up, further suggesting a link between obesity and aldosterone, she said.
Majewski also cited an analysis of mammary fat collected from otherwise healthy women who were undergoing breast-reduction surgery, in which researchers evaluated the genetic expression of various components of the renin-angiotensin-aldosterone system. The researchers reported significantly higher expression of renin, angiotensin-converting enzyme and angiotensin type-1 receptor among obese participants with hypertension.
The link between elevated aldosterone levels and obesity may be relevant for treatment-resistant hypertension, as many patients with this condition also have abdominal obesity. Aldosterone blockers such as spironolactone have been effective for lowering BP in this population, but are generally underused, Majewski said. She suggested that aldosterone blockers be considered for obese patients with hypertension, particularly treatment-resistant hypertension.
Majewski also stressed that obesity-related hyperaldosteronism is different than true primary hyperaldosteronism. Guidelines from The Endocrine Society recommend that screening for primary hyperaldosteronism occur in patients with hypertension and spontaneous/low-dose diuretic-induced hypokalemia; severe hypertension (>160 mm Hg systolic BP or >100 mm Hg diastolic BP); resistant hypertension; hypertension with adrenal adenoma; a family history of hypertension or cerebrovascular accident at a young age; and first-degree relatives with primary hyperaldosteronism. Medical management of primary hyperaldosteronism could include an aldosterone blocker such as spironolactone or eplerenone; amiloride or triamterene to block the renal effects of aldosterone; or potassium supplementation. In the event that primary aldosteronism is due to a single source, there is the potential for a surgical cure for these patients. – by Adam Taliercio
For more information:
Majewski CM. The Contribution of Aldosterone in Obesity-Related Hypertension. Presented at: Cardiometabolic Health Congress, Oct. 22-25, 2014; Boston.
Disclosure: Majewski reports no relevant financial disclosures.