Autonomic Dysfunction and Orthostatic Hypotension

Orthostatic hypotension (OH) is a significant medical condition, with a prevalence that varies depending on the studied population, from 6% in healthy elderly, to up to 54% of nursing home residents. About half of hospitalized elderly are affected by OH, and the rate of OH-related hospitalizations increases exponentially with age. Patients aged 75 years and older have the highest annual hospitalization rate of 233 per 100,000. OH patients endure substantial disabilities and impaired quality of life. OH is associated with a 2.6-fold increase in the risk of falls, and is an independent risk factor for all-cause mortality as well as cardiovascular morbidity and mortality. The typical OH patient is frail and elderly, with multiple comorbidities, polypharmacy, and a high health care burden. Hypertension is the most common comorbidity among patients with OH, affecting approximately 70% of OH patients. Conversely, OH is present in about 10% of patients referred to hypertension specialists. The strong association between OH and hypertension complicates the treatment of OH because of the opposing effect of drugs used for the treatment of these conditions. There is a paucity of randomized controlled clinical trials on which to base treatment recommendations. Thus, understanding of the pathophysiology of OH is important to establish an appropriate treatment regimen.