Table 5.

 Characteristics of included randomised controlled trials on hormone replacement therapy that reported venous thromboembolism

Reference	No of participants*	Clinical background	Duration of trial (years)	No of events		Adjusted risk ratio for venous thromboembolism (95% CI)
				Hormone replacement therapy group	Placebo group
PEPI 1995w12	847	“Healthy”	3	4	0†	1.9 (0.1 to 36.5)‡§
HERS 1998w13	2763	History of coronary heart disease	4.1	34	12	2.9 (1.5 to 5.6)
EVTET 2000w14	140	History of venous thromboembolism	1.3	8	1	7.8 (1.0 to 60.5)
ERA 2000w15	309	History of coronary heart disease	3.2	7	1¶	3.6 (0.5 to 28.9)‡
WEST 2001w16	664	History of stroke	2.8	3	4	0.8 (0.2 to 3.4)
ESPRIT 2002w17	1017	History of coronary heart disease	2	5	4	1.2 (0.3 to 4.6)
WHI I 2002w18	16608	“Healthy”	5.2	151	67	2.1 (1.6 to 2.7)
WHI II 2004w19	10739	“Healthy”	7	77	54	1.3 (1.0 to 1.8)
WISDOM 2007w20	5692	Possible history of arterial disease	0.99	22	3	7.4 (2.2 to 24.6)

*About equal number in placebo and active treatment group except for two trials.^{w12 w15}

†Hormone replacement therapy group n=682; placebo group n=165.

‡Risk calculated from data reported in study.

§To estimate risk ratio, number of events in placebo group was considered equal to 0.5.

¶Hormone replacement therapy group n=204; placebo group n=105.