Metabolomic profiles of metformin in breast cancer survivors: a pooled analysis of plasmas from two randomized placebo-controlled trials

Table 1 Participant baseline characteristics by treatment group in the pooled sample (ITA + USA)

	Placebo (N = 179)	Metformin (N = 194)	P-value^a
Weight loss intervention n (%)
No	96 (53.6%)	111 (57.2%)	0.554
Yes	83 (46.4%)	83 (42.8%)
Age, median (Q1, Q3)	63.0 (57.0, 67.0)	60.0 (56.0, 66.0)	0.031
BMI, median (Q1, Q3)	29.8 (27.5, 33.1)	30.0 (27.4, 33.4)	0.889
Menopausal status, n (%)
Post-menopausal	179 (100%)	183 (94.3%)	0.003
Pre-menopausal	0 (0%)	11 (5.7%)
Pathologic stage, n (%)
Stage I	85 (47.5%)	92 (47.4%)	0.986
Stage II	63 (35.2%)	68 (35.1%)
Stage III	31 (17.3%)	32 (16.5%)
Missing	0 (0%)	2 (1.0%)
Histology, n (%)
Invasive ductal carcinoma	130 (72.6%)	154 (79.4%)	0.310
Invasive lobular carcinoma	21 (11.7%)	17 (8.8%)
Other/unknown	28 (15.6%)	23 (11.9%)
Tumor grade, n (%)
Grade I	46 (25.7%)	49 (25.3%)	0.972
Grade II	75 (41.9%)	78 (40.2%)
Grade III	53 (29.6%)	62 (32.0%)
Unknown	5 (2.8%)	5 (2.6%)
Estrogen receptor status, n (%)
Negative	32 (17.9%)	51 (26.3%)	0.072
Positive	146 (81.6%)	143 (73.7%)
Missing	1 (0.6%)	0 (0%)
Progesterone receptor status, n (%)
Negative	45 (25.1%)	67 (34.5%)
Positive	126 (70.4%)	118 (60.8%)
Borderline/not noted	7 (3.9%)	9 (4.6%)	0.125
Missing	1 (0.6%)	0 (0%)
HER2 status, n (%)
Negative	143 (79.9%)	139 (71.6%)	0.341
Positive	31 (17.3%)	44 (22.7%)
Not noted/other	4 (2.2%)	5 (2.6%)
Missing	1 (0.6%)	6 (3.1%)
Aromatase inhibitor therapy, n (%)
No	84 (46.9%)	99 (51.0%)	0.491
Yes	95 (53.1%)	95 (49.0%)

^aP-values derived from Wilcoxon rank-sum test for numerical variables and from Chi-square test (or Fisher exact test, where appropriate) for categorical variables

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