Delayed orthostatic hypotension (DOH) is an earlier, milder form of orthostatic hypotension (OH), a decade-long study of patients at a single institution indicated.
The data showed that, over 10 years of follow-up, 54% of patients with DOH progressed to OH and that the 10-year mortality of patients who progressed to OH was 50%,
Christopher H. Gibbons, MD, of Beth Israel Deaconess Medical Center, Harvard Medical School in Boston, and colleagues reported online in
Neurology.
The increase in mortality in individuals with DOH was associated with progression to OH, abnormalities in baseline autonomic test results, the presence of diabetes, and the development of an alpha-synucleinopathy, said the investigators.
"Our data suggest that DOH falls along the continuum of severity and associated mortality risk associated with generalized autonomic dysfunction and with OH alone," said Gibbons. "The magnitude of the mortality in DOH approaches that associated with autonomic dysfunction in individuals with diabetes and other neurodegenerative disorders."
OH is currently defined as a fall of 20 mm Hg in systolic blood pressure or 10 mm Hg in diastolic pressure within 3 minutes of assuming a standing position. But some pressure drops occur after the 3-minute window; these cases have been dubbed delayed OH.
This delayed syndrome is now recognized as a potential cause of
orthostatic intolerance, but there are no
longitudinal data available, noted the investigators. Neither is it known whether delayed OH is an early presentation of OH, or a more benign or nonprogressive form of orthostatic intolerance.
While
a 1998 study suggested the DOH may be the culprit behind
chronic fatigue syndrome, findings from the present analysis suggest that more serious disorders may be involved. At the time of original testing, disorders associated with DOH included diabetes (16%), cardiac disease (14%), and pure autonomic failure (2%), noted the investigators.
