PREVALENCE AND RISK FACTORS OF ORTHOSTATIC HYPOTENSION IN THE POPULATION-BASED SWISS LONGITUDINAL COHORT STUDY (SWICOS)

Objective: The prevalence of orthostatic hypotension (OH) ranges from 5% to 30%. Most of these previous studies embraced highly selected study populations and there is scare data obtained in population-based studies. Therefore, we examined the prevalence and correlates of OH in the population-based SWICOS study. Design and method: The 496 SWICOS participants underwent blood pressure (BP) measurements after adequate rest as well as 1 and 3 minutes after standing up with a validated oscillometric device. OH was defined as a reduction of systolic BP of at least 20 mmHg and/or diastolic BP of at least 10 mmHg within 3 min of standing up from the sitting position. To assess the associations between baseline characteristics and OH, multivariate logistic regression models were performed, adjusted for age, sex, and other variables that showed a significant association with OH in univariate analysis. Results: Among 496 participants, 72 (14.5%) had OH. Participants with OH were significantly older than participants without [mean age 62y vs. 48y; p<0.001)]. Among the participants older than 60 years (n = 129), 38 individuals (30%) had OH. Participants with OH were more often affected by arterial hypertension (32% vs 13%; p<0.001) diabetes (10% vs 3%; p = 0.009), obesity (22% vs. 12%; p = 0.023), their muscle mass was lower (65% vs. 71%; p<0.001), and shorter walking distance (160 m vs. 170 m ; p<0.001). Participants with OH had a higher seated systolic (148mmHg vs. 129mmHg) and diastolic BP (88mmHg vs. 80mmHg) (both p<0.001). From 28 participants with OH who were on a prescription for antihypertensive drugs, 12 (43%) were taking more than one antihypertensive drug and/or a diuretic. Independent predictors for OH were increased systolic BP (OR per mmHg increase 1.05 (95%CI 1.03-1.07; p<0.001), higher number of prescribed antihypertensive drugs (OR 3.35; 95%CI 1.17-9.56; p = 0.024) and reduced walking distance (OR 0.99; 95%CI 0.98-1.00; p = 0.037). Conclusions: In our study, a higher systolic blood pressure, more intensive antihypertensive drug treatment as well as reduced walking distance were associated with OH. Adequate BP measurement, adequate selection of antihypertensive drug classes and regular physical activity may be effective preventive measures to reduce OH.