| Abstract
| - Abstract. Objectives To review completed trials assessing effect of hormone replacement therapy on subsequent risk of stroke, assessing stroke by pathological type, severity, and outcome. Table 1 Effect of hormone replacement therapy on stroke and its type and outcome, and transient ischaemic attackNo of trialsNo of subjectsNo of eventsControl event rate (%)Odds ratio* (95% CI), P valueHeterogeneity (P value)Stroke:2839 7699402.031.29 (1.13 to 1.47), 0.00020.56Ischaemic1623 4264431.591.29 (1.06 to 1.56), 0.010.59Haemorrhagic1723 690630.251.07 (0.65 to 1.75), 0.790.75Transient ischaemic attack2210 0502332.131.02 (0.78 to 1.34), 0.860.86Outcome:Fatal2236 4301290.291.28 (0.87 to 1.88), 0.210.39Non-fatal2136 2307101.721.23 (1.06 to 1.44), 0.0070.45Death or dependency1420 4451450.531.56 (1.11 to 2.20), 0.010.93 * Odds ratios calculated with random effects model. Design Systematic review of randomised controlled trials identified from the Cochrane Library, Embase, and Medline; reviews; and reference lists of relevant papers. Studies reviewed 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 (£ 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.
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