Method of hormone replacement therapy delivery and stroke risk

January 01, 0001

Method of hormone replacement therapy delivery and stroke risk

These Canadian and German researchers investigated the stroke risk associated with oral and transdermal hormone replacement therapy. They used a population based nested case-control study using the UK General Practice Research Database. They looked at all women in the database aged 50- 79 years without a diagnosis of stroke before cohort entry. For each case of stroke occurring during follow-up, up to four controls were selected from among the cohort members in the risk sets defined by the case. Hormone replacement therapy use was characterized using prescription records.

The researchers report: "There were 15,710 cases of stroke matched to 59,958 controls. The rate of stroke in the cohort was 2.85 per 1000 per year. The adjusted rate ratio of stroke associated with current use of transdermal HRT was 0.95 relative to no use. The risk of stroke was not increased with use of low oestrogen dose patches (rate ratio 0.81) compared with no use, whereas the risk was increased with high dose patches (rate ratio 1.89). Current users of oral HRT had a higher rate of stroke than non-users (rate ratio 1.28) with both low dose and high dose."

The authors concluded: "The use of transdermal HRT containing low doses of oestrogen does not seem to increase the risk of stroke. The presence of residual confounding, however, cannot be entirely excluded in the interpretation of this finding."

This study provides further evidence that oral and transdermal hormone replacement therapy increases stroke risk, but this may not be the case with low dose estrogen transdermal systems.

For the full abstract, click here.

BMJ 340:c2519, 3 June 2010
© 2010 Renoux et al.
Transdermal and oral hormone replacement therapy and the risk of stroke: a nested case-control study. Christel Renoux, Sophie Dell’Aniello, Edeltraut Garbe, Samy Suissa. Correspondence to S Suissa:

Category: K. Circulatory. Keywords: hormone replacement therapy, HRT, estrogen, transdermal, oral, nested case-control, journal watch.
Synopsis edited by Dr Paul Schaefer, Toledo, Ohio. Posted on Global Family Doctor 9 July 2010

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