AB334         DOES HORMONE REPLACEMENT THERAPY PROTECT AGAINST ISCHAEMIC HEART DISEASE? A CASE CONTROL STUDY

Author(s): 
Hippisley-Cox J, Pringle M, Crown N, Hammersley V, Coupland C
NOTTINGHAM, UK
Text: 
Background:
Many clinicians believe that hormone replacement therapy protects against coronary heart disease in women. This is because of meta-analyses of observational studies which show up to a 50% reduction in coronary events. The trials have used physiological or laboratory endpoints rather than clinical endpoints. Unintended selection of relatively healthy women for oestrogen therapy may have influenced the reported beneficial effect of oestrogen therapy on cardiovascular disease in those taking HRT. Given the numbers of postmenopausal women, the possible risks of HRT including breast cancer, gall bladder surgery, and deep vein thrombosis, it is important to establish the true cardiovascular benefits of HRT.
Aim: To determine the degree of cardioprotection conferred by HRT therapy including the effect of duration, recency of use, the addition of progestin, route of administration and dose.
Design: Population based case control study. Setting: Nine general practices recruited from the Trent Focus Collaborative Research Network. Subjects: 417 female cases with ischaemic heart disease matched by age and practice to 2435 controls. Main Outcome: Odds ratio for ischaemic heart disease calculated by logistic regression adjusted for diabetes, hypertension, body mass index and smoking.
Results: We found no evidence that use of HRT was associated with reduced risk of ischaemic heart disease either on univariate analysis or multivariate analysis (OR 1.20 95% CI 0.78-1.84). There was no association for different types of HRT (opposed or unopposed) or routes of administration; no association for current or past use, no effect for dose or duration.