Background:
Clinic blood pressure (BP) is measured in the seated position, which can miss important home BP phenotypes such as low ambulatory BP (white coat effects) or high supine BP (nocturnal non-dippers). Orthostatic hypotension (OH) is determined based on BP measurements in both seated (or supine) and standing positions, and thus could theoretically identify these important phenotypes in clinic.
Objective:
To determine the association of OH with white coat effects or night-to-daytime systolic BP (SBP)
Methods:
SPRINT was a randomized trial testing the effects of intensive (<120 mmHg) or standard (<140 mmHg) SBP treatment strategies in adults at higher risk of cardiovascular disease. OH was assessed at 6, 12, or 24-mths and defined as a decrease in standing and mean seated SBP ≥20 or DBP ≥10 mmHg after 1 min of standing. White coat effects, based on 24-hr ambulatory BP monitoring performed at the 27-mth visit (every 30-minutes), were defined as the difference between 27-mth seated clinic and ambulatory BP ≥ 20/≥10 mmHg. SBP dipping ratio was defined as the ratio of night-to-daytime SBP >0.9.
Results:
Of 897 adults (mean age 71.5 [SD, 9.5] yrs, 28.7% female, 28.0% black), 128 had OH at least once. Among those with OH, 14.8% had white coat effects versus 7.2% among those without OH. Moreover, 68.8% of those with OH demonstrated non-dipping patterns versus only 52.0% of those without OH. OH was positively associated with both white coat effects (OR=2.24; 95% CI: 1.28, 4.27) and higher night-to-daytime SBP (β=0.04; 95% CI: 0.02, 0.06) (
Table
).
Conclusions:
Clinic-based assessments of OH may be a useful tool for identifying BP phenotypes often missed with traditional seated BP assessments.
Home versus clinic blood pressure monitoring in the assessment of the antihypertensive efficacy of combination pharmacotherapy