[What is the most relevant definition of orthostatic hypotension: systolic blood pressure drop, diastolic blood pressure drop, or both?].

UNLABELLED: The agreed definition of orthostatic hypotension (OH) is a drop of 20 mmHg systolic and/or 10 mmHg diastolic blood pressure (BP) within the first 3 min of erect posture. For elderly people, a question can be raised about diastolic BP relevance in OH's definition.

OBJECTIVE

To determinate HO's prevalence and risks factors considering systolic blood pressure (SBP)'s drop, or diastolic blood pressure (DBP)'s drop, or either.

METHODS

We assessed OH for 554 consecutive, ambulatory, elderly subjects, attending a geriatric outpatient clinic. OH was defined as a SBP drop>20mmHg (SBP-OH), or a DBP drop>10 mmHg (DBP-OH), or a drop in either (SBP. DBP-OH). OH's prevalence and risks factors were determined.

RESULTS

In this population, 76 +/- 6 years of age, (70% hypertension), SBP-OH's prevalence was 17%, DBP-OH's prevalence was 12% and SBP. DBP-OH's prevalence was 25%. OH's risks factors varied considering OH's definition. After adjusting for significant determinants, SBP-OH's risk factors were: Antihypertensive therapy (OR=2.95; IC 95%: 1.21-4.04), age>75years (OR=2.11; IC 95%: 1.22-3.66), anti-hypertensive poly therapy (OR=2.01; IC 95%: 1.39-2.92) and SBP level (OR=1.16; IC 95%: 1.01-1.33). Considering DBP-OH, the only significant risk factor was DBP's level (OR=2.64; IC 95%: 1.89-3.68). SBP. DBP-OH was only determined by anti-hypertensive poly therapy (OR=1.61; IC 95%: 1.13-2.29) and DPB level (OR=1.32; IC 95%: 1.08-1.60).

CONCLUSION

For elderly people, OH's prevalence and risks factors vary considering OH's definition. SBP's drop seems to be more relevant than DBP's drop. A long term follow up is necessary to determine if SBP-OH is correlated with HO' s side effects and to establish the dangerous level of SBP' s drop.