. 2022 Oct 24;152(4):572–599. doi: 10.1002/ijc.34322

TABLE 2.

Subgroup meta‐analyses of postdiagnosis body mass index and breast cancer outcomes by disease characteristics

Subgroup by disease characteristics ^a	All‐cause mortality Summary RR (95% CI) I ², P heterogeneity	Breast cancer mortality Summary RR (95% CI) I ², P heterogeneity	Breast cancer recurrence Summary RR (95% CI) I ², P heterogeneity
Menopausal status
Premenopausal	5 studies, 1812 deaths 1.10 (1.02‐1.20) 27%, 0.24	4 studies, 193 deaths 1.35 (1.08‐1.70) 21%, 0.29	6 studies, 2575 events 1.23 (1.06‐1.42) 77%, 0.001
Postmenopausal	10 studies, 4924 deaths 1.06 (0.99‐1.13) 68%, 0.001 P meta‐regression .52	6 studies, 1329 deaths 1.12 (1.07‐1.18) 0%, 0.45 P meta‐regression .14	9 studies, 5059 events 1.06 (1.02‐1.11) 23%, 0.24 P meta‐regression .17
Hormone receptor subtype
ER+ and/or PR+	5 studies, 1048 deaths 1.10 (0.96‐1.26) 67%, 0.02	2 studies, 520 deaths 1.70 (0.57‐5.06) 65%, 0.09	5 studies, 2557 events 1.06 (1.01‐1.11) 0%, 0.51
ER+	8 studies, 4640 deaths 1.11 (1.07‐1.15) 0%, 0.45	3 studies, 925 deaths 1.09 (1.01‐1.18) 0%, 0.75	7 studies, 4097 events 1.06 (1.02‐1.11) 25%, 0.24
ER+/PR+	2 studies, 433 deaths 1.03 (0.90‐1.17) 2%, 0.31	—	—
ER−	6 studies, 2005 deaths 1.09 (1.04‐1.14) 0%, 0.55	4 studies, 700 deaths 1.05 (0.97‐1.13) 1%, 0.32 P meta‐regression .50	6 studies, 2989 events 1.06 (1.02‐1.11) 0%, 0.91
ER−/PR−	3 studies, 235 deaths 1.20 (1.00‐1.42) 35%, 0.22 P meta‐regression .18	—	2 studies, 189 events 1.22 (1.06‐1.40) 0%, 0.48 P meta‐regression .60
Molecular subtype
ER+ and/or PR+/HER2−	2 studies, 1491 deaths 1.24 (1.14‐1.33) 0%, 0.66	2 studies, 973 deaths 1.01 (0.78‐1.31) 86%, 0.008	—
ER+ and/or PR+/HER2+	3 studies, 794 deaths 1.04 (0.94‐1.16) 0%, 0.79	—	2 studies, 691 events 1.01 (0.92‐1.11) 0%, 0.65
Triple negative/basal‐like	7 studies, 2364 deaths 1.03 (0.98‐1.09) 0%, 0.42	2 studies, 726 deaths 1.03 (0.88‐1.20) 13%, 0.28	5 studies, 1174 events 0.97 (0.83‐1.13) 46%, 0.12
HER2+	4 studies, 1566 deaths 1.03 (0.96‐1.11) 19%, 0.30 P meta‐regression .12	—	5 studies, 2056 events 1.06 (1.00‐1.11) 4%, 0.38 P meta‐regression .59
Invasiveness of tumor
Invasive	55 studies, 30 735 deaths 1.07 (1.04‐1.09) 58%, <0.001	32 studies, 13 160 deaths 1.08 (1.04‐1.13) 62%, <0.001	50 studies, 27 035 events 1.05 (1.03‐1.07) 38%, 0.007
Invasive and in situ	8 studies, 1576 deaths 1.12 (1.04‐1.22) 34%, 0.16 P meta‐regression .41	5 studies, 631 deaths 1.26 (1.09‐1.46) 41%, 0.15 P meta‐regression .21	5 studies, 1377 events 1.19 (1.08‐1.30) 34%, 0.20 P meta‐regression .02
Nodal status
Node+	6 studies, 5556 deaths 1.06 (1.03‐1.10) 0%, 0.48	—	6 studies, 6504 events 1.06 (1.03‐1.09) 0%, 0.68
Node‐	6 studies, 2168 deaths 1.09 (1.04‐1.15) 0%, 0.78 P meta‐regression .35	5 studies, 1292 deaths 1.08 (0.98‐1.19) 45%, 0.17	5 studies, 2618 events 1.04 (1.00‐1.09) 0%, 0.46 P meta‐regression .50
Cancer stage
Early stage/stage 0‐III/nonmetastatic	30 studies, 20 393 deaths 1.08 (1.04‐1.12) 67%, <0.001	16 studies, 7856 deaths 1.11 (1.05‐1.17) 72%, <0.001	27 studies, 15 677 events 1.06 (1.04‐1.07) 0%, 0.54
Stage 0‐II	2 studies, 438 deaths 1.20 (1.02‐1.40) 22%, 0.26	—	3 studies, 659 events 1.06 (0.77‐1.45) 80%, 0.002
Locally advanced/stage III	4 studies, 411 deaths 0.98 (0.88‐1.09) 35%, 0.21	—	3 studies, 396 events 1.02 (0.87‐1.20) 52%, 0.13
Stage IV/distant/metastatic	5 studies, 761 deaths 0.95 (0.87‐1.04) 0%, 0.66 P meta‐regression .14	—	8 studies, 1057 events 0.91 (0.86‐0.96) 0%, 0.74 P meta‐regression .003

Subgroup by disease characteristics ^a

All‐cause mortality Summary RR (95% CI) I ², P heterogeneity

Breast cancer mortality Summary RR (95% CI) I ², P heterogeneity

Breast cancer recurrence Summary RR (95% CI) I ², P heterogeneity

Menopausal status

Premenopausal

5 studies, 1812 deaths

1.10 (1.02‐1.20)

27%, 0.24

4 studies, 193 deaths

1.35 (1.08‐1.70)

21%, 0.29

6 studies, 2575 events

1.23 (1.06‐1.42)

77%, 0.001

Postmenopausal

10 studies, 4924 deaths

1.06 (0.99‐1.13)

68%, 0.001

P meta‐regression .52

6 studies, 1329 deaths

1.12 (1.07‐1.18)

0%, 0.45

P meta‐regression .14

9 studies, 5059 events

1.06 (1.02‐1.11)

23%, 0.24

P meta‐regression .17

Hormone receptor subtype

ER+ and/or PR+

5 studies, 1048 deaths

1.10 (0.96‐1.26)

67%, 0.02

2 studies, 520 deaths

1.70 (0.57‐5.06)

65%, 0.09

5 studies, 2557 events

1.06 (1.01‐1.11)

0%, 0.51

ER+

8 studies, 4640 deaths

1.11 (1.07‐1.15)

0%, 0.45

3 studies, 925 deaths

1.09 (1.01‐1.18)

0%, 0.75

7 studies, 4097 events

1.06 (1.02‐1.11)

25%, 0.24

ER+/PR+

2 studies, 433 deaths

1.03 (0.90‐1.17)

2%, 0.31

—

ER−

6 studies, 2005 deaths

1.09 (1.04‐1.14)

0%, 0.55

4 studies, 700 deaths

1.05 (0.97‐1.13)

1%, 0.32

P meta‐regression .50

6 studies, 2989 events

1.06 (1.02‐1.11)

0%, 0.91

ER−/PR−

3 studies, 235 deaths

1.20 (1.00‐1.42)

35%, 0.22

P meta‐regression .18

—

2 studies, 189 events

1.22 (1.06‐1.40)

0%, 0.48

P meta‐regression .60

Molecular subtype

ER+ and/or PR+/HER2−

2 studies, 1491 deaths

1.24 (1.14‐1.33)

0%, 0.66

2 studies, 973 deaths

1.01 (0.78‐1.31)

86%, 0.008

—

ER+ and/or PR+/HER2+

3 studies, 794 deaths

1.04 (0.94‐1.16)

0%, 0.79

—

2 studies, 691 events

1.01 (0.92‐1.11)

0%, 0.65

Triple negative/basal‐like

7 studies, 2364 deaths

1.03 (0.98‐1.09)

0%, 0.42

2 studies, 726 deaths

1.03 (0.88‐1.20)

13%, 0.28

5 studies, 1174 events

0.97 (0.83‐1.13)

46%, 0.12

HER2+

4 studies, 1566 deaths

1.03 (0.96‐1.11)

19%, 0.30

P meta‐regression .12

—

5 studies, 2056 events

1.06 (1.00‐1.11)

4%, 0.38

P meta‐regression .59

Invasiveness of tumor

Invasive

55 studies, 30 735 deaths

1.07 (1.04‐1.09)

58%, <0.001

32 studies, 13 160 deaths

1.08 (1.04‐1.13)

62%, <0.001

50 studies, 27 035 events

1.05 (1.03‐1.07)

38%, 0.007

Invasive and in situ

8 studies, 1576 deaths

1.12 (1.04‐1.22)

34%, 0.16

P meta‐regression .41

5 studies, 631 deaths

1.26 (1.09‐1.46)

41%, 0.15

P meta‐regression .21

5 studies, 1377 events

1.19 (1.08‐1.30)

34%, 0.20

P meta‐regression .02

Nodal status

Node+

6 studies, 5556 deaths

1.06 (1.03‐1.10)

0%, 0.48

—

6 studies, 6504 events

1.06 (1.03‐1.09)

0%, 0.68

Node‐

6 studies, 2168 deaths

1.09 (1.04‐1.15)

0%, 0.78

P meta‐regression .35

5 studies, 1292 deaths

1.08 (0.98‐1.19)

45%, 0.17

5 studies, 2618 events

1.04 (1.00‐1.09)

0%, 0.46

P meta‐regression .50

Cancer stage

Early stage/stage 0‐III/nonmetastatic

30 studies, 20 393 deaths

1.08 (1.04‐1.12)

67%, <0.001

16 studies, 7856 deaths

1.11 (1.05‐1.17)

72%, <0.001

27 studies, 15 677 events

1.06 (1.04‐1.07)

0%, 0.54

Stage 0‐II

2 studies, 438 deaths

1.20 (1.02‐1.40)

22%, 0.26

—

3 studies, 659 events

1.06 (0.77‐1.45)

80%, 0.002

Locally advanced/stage III

4 studies, 411 deaths

0.98 (0.88‐1.09)

35%, 0.21

—

3 studies, 396 events

1.02 (0.87‐1.20)

52%, 0.13

Stage IV/distant/metastatic

5 studies, 761 deaths

0.95 (0.87‐1.04)

0%, 0.66

P meta‐regression .14

—

8 studies, 1057 events

0.91 (0.86‐0.96)

0%, 0.74

P meta‐regression .003

Abbreviations: CI, Confidence interval; ER, oestrogen receptor; HER2, human epidermal growth factor receptor 2; PR, progesterone receptor; RR, relative risk.

^{^a}

Results not shown for the strata with only one study or the few studies with unknown information.