Name: Ana Paula Costa Velten
Type: PhD thesis
Publication date: 18/04/2018
Advisor:

Namesort descending Role
Jose Geraldo Mill Advisor *

Examining board:

Namesort descending Role
Jose Geraldo Mill Advisor *

Summary: Orthostatic hypotension (OH) is a sustained reduction in blood pressure when the
individual stands up from lying down. OH occurs as consequence of failure in
compensatory mechanisms of reduced venous return. In population studies, OH has
been associated with cardiovascular comorbidities such as coronary artery disease,
atrial fibrillation, hypertension, heart failure, stroke, arterial stiffness and chronic
kidney disease. Besides the risk factors for OH have been neglected in clinical
practice, few epidemiological studies have dedicated to this subject. Moreover,
studies in the Brazilian population are a missing. This thesis sought to estimate the
prevalence of OH and its associated factors among participants of the Brazilian
cohort "Longitudinal Study of Adult Health" (ELSA-Brazil). Data collected at baseline
were used for 14,833 participants (both sexes, 35-74 years) who had complete data
of postural maneuver. The postural maneuver was performed after 20 minutes rest in
the supine position by active adoption of stand up posture. Blood pressure (BP) was
measured at both supine and at 2, 3 and 5 minutes of orthostasis. OH was defined
as a fall ≥20 mmHg in systolic BP and / or a fall ≥10 mmHg in diastolic BP at 3
minutes of orthostasis. The distribution of BP variation after the postural maneuver
was determined in a subsample (N = 8,011) after exclusion of participants with
cardiovascular morbidity and diabetes. Associated factors were determined by a
cross sectional study. The covariates analyzed were gender, age range, race/skin
color, schooling, nutritional status, waist circumference, changes in brachial ankle
index, pulse wave velocity, heart disease, acute myocardial infarction
(AMI)/revascularization, stroke, diabetes, hypertension, antihypertensive medication
use, systolic and diastolic pressure, cholesterol, triglycerides, Chagas serology,
presence of symptoms and variation of heart rate. The total prevalence of OH was
2.0% (95% CI: 1.8-2.3) and similar between sexes, with increasing frequency with
age (1.2% at age <45 years and 3.4% at age > 65 years). When pressure drop in any
time measured was used as criterion, the prevalence of OH increased to 4.3% (95%
CI: 4.0-4.7). Symptoms as dizziness, visual changes and nausea were self-reported
in 19.7% (95% CI: 15.6-24.6) of the participants with OH and only in 1.4% (95% CI:
1.2 -1.6) of the participants without HO. The -2 Z-scores of the pressure variations
before and after the postural maneuver in the sub-sample were -14.1 mmHg in the
systolic BP and -5.4 mmHg in the diastolic BP. OH was significantly associated with
largest age group, OR: 1.83 (95% CI: 1.14-2.95); changes in brachial ankle index,
OR: 2.8 (95% CI: 1.13-6.88), AMI/ revascularization, OR: 1.70 (95% CI: 1.01-2.87);
self-reported heart disease, OR: 3.03 (95% CI: 1.71-5.36); increased systolic BP,
OR: 1.012 (95% CI: 1.006-1.019); positive Chagas disease serology, OR: 2.29 (95%
IC: 1.23-4.27) and self-reported symptoms in postural change, OR: 20.81 (95% CI:
14.81-29.24). The prevalence of OH varied substantially depending on the moment
of pressure measurement. The current cutoff points adopted may underestimate the
actual occurrence of OH in the population. The presence of OH could be very useful
as an alert for potential cardiovascular impairment, and therefore a tool for screening
and prevention

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