Association between hormone replacement therapy and subsequent stroke: a meta-analysis.
OBJECTIVE
To review completed trials assessing effect of hormone replacement therapy on subsequent risk of stroke, assessing stroke by pathological type, severity, and outcome.


METHODS
Systematic review of randomised controlled trials identified from the Cochrane Library, Embase, and Medline; reviews; and reference lists of relevant papers.


METHODS
28 trials, with 39 769 subjects, were identified. REVIEW MEASURES: Rates for cerebrovascular events analysed with a random effects model. Sensitivity analyses for heterogeneity included phase of prevention (primary or secondary), type of hormone replacement therapy (oestrogen alone or combined with progesterone), type of oestrogen (estradiol or conjugated equine oestrogen), size of trial (< 5000 or > 5000 patients), length of follow up ( pound 3 years or > 3 years), sex (women only or men only), and trial quality (high or low).


RESULTS
Hormone replacement therapy was associated with significant increases in total stroke (odds ratio 1.29 (95% confidence interval 1.13 to 1.47), n = 28), non-fatal stroke (1.23 (1.06 to 1.44), n = 21), stroke leading to death or disability (1.56 (1.11 to 2.20), n = 14), ischaemic stroke (1.29 (1.06 to 1.56), n = 16), and a trend to more fatal stroke (1.28 (0.87 to 1.88), n = 22). It was not associated with haemorrhagic stroke (1.07 (0.65 to 1.75), n = 17) or transient ischaemic attack (1.02 (0.78 to 1.34), n = 22). Statistical heterogeneity was not present in any analysis.


CONCLUSIONS
Hormone replacement therapy was associated with an increased risk of stroke, particularly of ischaemic type. Among subjects who had a stroke, those taking hormone replacement therapy seemed to have a worse outcome. Hormone replacement therapy cannot be recommended for the primary or secondary prevention of stroke.
Bath
Philip M W
PM
Division of Stroke Medicine, Institute of Neuroscience, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH. philip.bath@nottingham.ac.uk
Gray
Laura J
LJ
D000368:Aged; D003625:Data Collection / Q000592:standards; D005260:Female; D020249:Hormone Replacement Therapy / Q000009:adverse effects*; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause; D011379:Prognosis; D016032:Randomized Controlled Trials as Topic / Q000592:standards; D012307:Risk Factors; D020521:Stroke / Q000139:chemically induced* / Q000473:pathology* / Q000517:prevention & control