Obesity-associated hypertension

Abstract

Both hypertension and obesity are highly prevalent chronic medical conditions that af fl ict an increasing portion of both the adult and the pediatric populations in clinical practice worldwide. Based on the sheer prevalence of both of these conditions, it is not unexpected to discover that they often coexist. There is, however, considerable retrospective, cross-sectional and prospective data from various research studies and diverse populations which suggest that the association between obesity and so-called ''essential hypertension'' is signi fi cantly more prevalent than the result of chance co-occurrence. A growing body of data suggests that obesity has a direct, independent, and causal link to the onset and worsening of hypertension. This association now known as obesity-hypertension (OH) has also been shown to be significantly ameliorated by significant (>5% of baseline body weight) weight loss. While the exact underlying etiopathogenesis of OH is still unclear, it appears to be multifactorial including both mechanical and humoral factors in its development. Among the identi fi ed putative contributory factors are renal salt retention, blood volume expansion, and sympathetic activation all of which can be induced by hyperinsulinemia and hyperleptinemia. Hypoadiponectinemia, activation of the reninangiotensin- aldosterone system (RAAS) as well as the elevated levels of circulating endothelin and free fatty acids also likely play contributing roles. The high prevalence of obstructive sleep apnea (OSA) in the setting of obesity is another pathophysiologic link to the onset of hypertension in obese subjects whose importance is only recently being fully appreciated. In addition to the well-established complications and comorbidities known to be associated with hypertension and obesity, OH as an entity appears to be associated with some distinctive cardiomyopathic features. This, in addition to issues related to accurate blood pressure measurement and tracking in obese subjects, requires some expertise and extra care on the part of clinical providers who care for these patients. The management of OH while based on the same general principles applied to management of essential hypertension as a whole has the added blood pressure modulating effects that follow sustained weight loss. More research into the dominant pathophysiologic mechanisms and treatment strategies for drug-resistant OH is needed.