The association between orthostatic hypotension and medication use in the British Women's Heart and Health Study

Design: cross-sectional analysis using data from the British Women's Heart and Health Study. Setting: general practices in 23 towns in the UK. Participants: 3,775 women aged 60-80 years from 1999 to 2001. Main outcome measure: orthostatic hypotension-drop of >= 20 mmHg in systolic and/or a drop of >= 10 mmHg in diastolic blood pressure on standing. Results: prevalence of OH was 28% (95% confidence interval [CI] 26.6, 29.4), which increased with age and hypertension. Regardless of treatment status or diagnosed hypertension, raised blood pressure was strongly associated with OH (P < 0.001). OH was strongly associated with number of antihypertensives taken (none vs three or more: odds ratio [OR] 2.24, 95% CI 1.47-3.40, P < 0.001); the association was slightly attenuated after allowing for age and co-morbidities (OR 1.99; 95% CI 1.30, 3.05; P = 0.003). Women with multiple co-morbidities had markedly increased odds of OH independent of age, number and type of medications taken (none vs four or more diagnoses: OR 2.28, 95% CI 1.58-3.30, P = 0.005). Conclusion: uncontrolled hypertension, use of three or more antihypertensives and multiple co-morbidities are predictors of OH in older women. Detection or monitoring of OH in these groups may prevent women from suffering its adverse consequences.