Abstract: FR-PO580

Prevalence and Predictors of Orthostatic Hypotension at a Tertiary Care Hypertension Clinic with New Diagnostic Thresholds

Session Information

Category: Hypertension

  • 1104 Hypertension: Clinical and Translational - Salt and Hypertension

Authors

  • Faraz, Mohammad Ali, University of Ottawa, Ottawa, Ontario, Canada
  • Ruzicka, Marcel, None, Ottawa, Ontario, Canada
  • Hiremath, Swapnil, University of Ottawa, Ottawa, Ontario, Canada
Background

Formal testing of orthostatic hypotension (OH), defined as a decrease of blood pressure (BP) of 20/10 mm Hg (systolic/diastolic) on change in posture from supine to standing, is seldom carried out in routine practice because of logistical constraints. A recent study reported a sit-to-stand decrease of 15/7 mm Hg as having high sensitivity and specificity. We measured the prevalence and risk factors associated with OH with the new threshold of sit-to- stand of either ≥15 mm Hg in systolic (SBP) or ≥ 7 mm Hg in diastolic BP (DBP).

Methods

We reviewed medical charts of patients being followed at Renal Hypertension Center, a referral centre for difficult to control hypertension. Sitting BP is measured after 5 minutes of resting, as an average of 5 measurements with an automated device. Standing BP is measured three times at one minute intervals and averaged. OH was determined on the basis of the difference in either average SBP or DBP. Demographic characteristics, comorbidities, medication details, laboratory values and BP measurements were extracted.

Results

Data from 219 patients was extracted. The overall difference in SBP (sitting - standing) was 0.94 and DBP was 2.1 mm Hg. 190 patients (87%) did not have OH, whereas 29 (13%) had OH using either SBP or DBP thresholds. The difference in SBP and DBP was 17 mm and 6 mm Hg in those with OH, versus 1.6 and 3 mm Hg amongst those without OH respectively. Higher sitting systolic BP was
significantly associated with OH; age, gender, diabetes, number and hypertension medication class were not associated with OH.

Conclusion

Amongst referred patients to a specialist hypertension clinic, the prevalence of OH using a threshold of 15/7 mm Hg was 13%. The new diagnostic threshold allows for easy assessment of OH.