Single Agent Antihypertensive Therapy and Orthostatic Blood Pressure Behaviour in Older Adults Using Beat-to-Beat Measurements: The Irish Longitudinal Study on Ageing.

BACKGROUND

Impaired blood pressure (BP) stabilisation after standing, defined using beat-to-beat measurements, has been shown to predict important health outcomes. We aimed to define the relationship between individual classes of antihypertensive agent and BP stabilisation among hypertensive older adults.

METHODS

Cross-sectional analysis from The Irish Longitudinal Study on Ageing, a cohort study of Irish adults aged 50 years and over. Beat-to-beat BP was recorded in participants undergoing an active stand test. We defined grade 1 hypertension according to European Society of Cardiology criteria (systolic BP [SBP] 140-159 mmHg ± diastolic BP [DBP] 90-99 mmHg). Outcomes were: (i) initial orthostatic hypotension (IOH) (SBP drop ≥40 mmHg ± DBP drop ≥20 mmHg within 15 seconds [s] of standing accompanied by symptoms); (ii) sustained OH (SBP drop ≥20 mmHg ± DBP drop ≥10 mmHg from 60 to 110 s inclusive); (iii) impaired BP stabilisation (SBP drop ≥20 mmHg ± DBP drop ≥10 mmHg at any 10 s interval during the test). Outcomes were assessed using multivariable-adjusted logistic regression.

RESULTS

A total of 536 hypertensive participants were receiving monotherapy with a renin-angiotensin-aldosterone-system inhibitor (n = 317, 59.1%), beta-blocker (n = 89, 16.6%), calcium channel blocker (n = 89, 16.6%) or diuretic (n = 41, 7.6%). A further 783 untreated participants met criteria for grade 1 hypertension. Beta-blockers were associated with increased odds of initial OH (OR 2.05, 95% CI 1.31-3.21) and sustained OH (OR 3.36, 95% CI 1.87-6.03) versus untreated grade 1 hypertension. Multivariable adjustment did not attenuate the results. Impaired BP stabilisation was evident at 20 s (OR 2.59, 95% CI 1.58-4.25) and persisted at 110 s (OR 2.90, 95% CI 1.64-5.11). No association was found between the other agents and any study outcome.

CONCLUSION

Beta-blocker monotherapy was associated with a >2-fold increased odds of initial OH and a >3-fold increased odds of sustained OH and impaired BP stabilisation, compared to untreated grade 1 hypertension. These findings support existing literature questioning the role of beta-blockers as first line agents for essential hypertension.