SEX-DIFFERENCES IN ANTIHYPERTENSIVE DRUG-USE - DETERMINANTS OF THE CHOICE OF MEDICATION FOR HYPERTENSION

Objective To describe and explain sex differences in antihypertensive drug use. Design and methods From 1987 to 1995, two cross-sectional po pulation-based surveys of cardiovascular disease risk factors in The N etherlands were carried out among 56 026 men and women aged 20-59 year s. Polytomous logistic regression modelling was used to adjust for pot ential confounders of the association between sex and use of different antihypertensive drugs. Results The response rate was 40% for men and 46% for women. Of these respondents, 40% (1041) of the hypertensive m en and 59% (1403) of the hypertensive women were being treated pharmac ologically; 57% (595) of the treated men and 54% (760) of the treated women were on monotherapy for hypertension with a diuretic (men 14.8%, women 37.2%), a beta-blocker (men 59.0%, women 45.3%), a calcium anta gonist (men 8.6%, women 5.0%) or an angiotensin converting enzyme inhi bitor (men 17.7%, women 12.5%). Among those on monotherapy for hyperte nsion, women were less likely than men to be using a beta-blocker [pre valence odds ratio (POR), female/male = 0.34; 95% confidence interval (CI) 0.24-0.47], a calcium antagonist (POR = 0.27, 95% CI 0.15-0.48) o r an angiotensin converting enzyme inhibitor (POR = 0.34, 95% CI 0.22- 0.52) than a diuretic. These sex differences persisted after adjustmen t for all factors that could have influenced the choice of these antih ypertensive drugs (indications and contra-indications for the four ant ihypertensive drug classes). The sex differences in antihypertensive d rug use were smaller among hypertensives with a history of cardiovascu lar disease (adjusted PORs, female/male, for beta-blockers, calcium an tagonists and ACE inhibitors, respectively, compared to diuretics were 0.80 with 95% CI 0.20-3.24, 0.40 with 95% CI 0.10-0.48 and 0.64 with 95% CI 0.12-3.39) than among those without such a history. Conclusions The different patterns of antihypertensive drug use among hypertensiv e men and women seem irrational, and cannot be explained by factors kn own to influence antihypertensive drug choice. Among hypertensives wit h a history of cardiovascular disease, the sex differences were smalle r than among those without such a history. Further research is require d to explain the sex differences in the choice of antihypertensive dru g by prescribers, and to investigate the consequences of these differe nces for long-term patient outcomes. (C) 1998 Lippincott Williams & Wi lkins.