Orthostatic hypotension is a more robust predictor of cardiovascular events than nighttime reverse dipping in elderly

Abstract

Aims of the study were to assess in an elderly population the prevalences of orthostatic hypotension at different times after standing and of nighttime reverse dipping on ambulatory blood pressure monitoring, as well as their interrelationships and relative prognostic power for incident cardiovascular events. The study population consisted of 374 patients (225 women), aged 70.2+/-8.5 years, registered in 1 primary care practice and without major cardiovascular events or other comorbidities at baseline. They experienced 76 first cardiovascular events (death, myocardial infarction, or stroke) during 3406 years of follow-up. Systolic/diastolic orthostatic hypotension, defined as a decrease of systolic/diastolic blood pressure of >or=20/>or=10 mm Hg, was present in 24.0%/13.3% of the patients immediately after standing, and in, respectively, 18.1%/10.5% and 12.4%/11.6% after 1 and 2 minutes, whereas systolic/diastolic reverse dipping occurred in 14.4%/9.5%. Orthostatic hypotension was 2 to 3 times more prevalent in reverse dippers than in dippers (P<or=0.01). Systolic orthostatic hypotension was a significant and independent predictor of cardiovascular events, which was stronger during recovery than immediately after standing; in Cox regression analysis, the adjusted hazard ratio amounted to 2.38 (P<0.01) after 2 minutes. The independent predictive power of diastolic orthostatic hypotension was only significant soon after standing (P<0.05). Systolic and diastolic reverse dipping carried prognostic significance in univariable analyses (P<0.001) but not after adjustment for confounders, including 24-hour blood pressure. We conclude that orthostatic hypotension contributes to the phenomenon of reverse dipping but is a more robust predictor of cardiovascular events than reverse dipping in the elderly of the current study.