Abstract
OBJECTIVE: To determine the effects of orthostatic hypotension (OH) measurement timing on its associations with dizziness, falls, fractures, cardiovascular disease (CVD), and mortality. METHODS: We analyzed OH measurements from the Action to Control Cardiovascular Risk in Diabetes BP trial, which evaluated two blood pressure (BP) goals (systolic BP [SBP] < 120 mm Hg vs. SBP < 140 mm Hg) and incident CVD among adults with diabetes and hypertension. Seated BP was measured after 5 minutes of rest at baseline and follow-up visits (12 months, 48 months, and exit). Standing BP was measured 3 consecutive times (M1-M3) after standing, starting at 1 minute with each measurement separated by 1 minute. Consensus OH was defined as a drop in SBP ≥ 20 mm Hg or diastolic BP (DBP) ≥ 10 mm Hg. Participants were asked about orthostatic dizziness, recent falls, and recent fractures, and underwent surveillance for CVD events and all-cause mortality. RESULTS: There were 4,268 participants with OH assessments over 8,450 visits (mean age 62.6 years [SD = 6.6]; 46.6% female; 22.3% black). Although all measures of consensus OH were significantly associated with dizziness, none were associated with falls, and only M2 (~3 minutes) was significantly associated with fractures. No measurements were associated with CVD events, but later measurements were significantly associated with mortality. BP treatment goal did not increase risk of OH regardless of timing. Associations were not consistently improved by the mean or minimum of M1-M3. CONCLUSION: In this population of adults with hypertension and diabetes, neither single time nor set of measurements were clearly superior with regard to outcomes. These findings support the use of a flexibly timed, single measurement to assess OH in clinical practice. CLINICAL TRIALS REGISTRATION: Trial Number NCT00000620.