Table 3.

Results of subgroup analyses for effects of ESR1 mutation on PFS

ESR1 mutation	ESR1 mutation numbers	df	Model	HR (95% CI)	Test for heterogeneity (I2)
D538G vs WT ESR1	121	2	Fixed	1.50 (1.18–1.91)	0.0%
Y537S vs WT ESR1	61	2	Random	1.65 (0.87–1.73)	83.7%

Abbreviations: df, degrees of freedom; HR, hazard ratio; PFS, progression-free survival; WT, wild type.