Retrospective Cohort Study
Copyright ©The Author(s) 2017.
World J Gastroenterol. Jul 28, 2017; 23(28): 5196-5205
Published online Jul 28, 2017. doi: 10.3748/wjg.v23.i28.5196
Table 1 Patient demographics and baseline clinical characteristics n (%)
Metformin group, n = 185Non-metformin group, n = 228P value
Age at diagnosis in yr, mean ± SD63.5 ± 8.78963.49 ± 10.2180.991
< 5012 (6.5)27 (11.8)0.064
≥ 50173 (93.5)201 (88.2)
Sex0.921
Male125 (67.6)153 (67.1)
Female60 (32.4)75 (32.9)
DM duration in yr, median (range)8 (1-120)6 (1-40)0.068
Family history of CRC8 (4.3)13 (5.7)0.526
BMI in kg/m2, mean ± SD23.6 ± 3.023.5 ± 3.00.596
Normal < 25148 (80.0)173 (76.5)0.300
Overweight 25-3033 (17.8)51 (22.6)
Obese ≥ 304 (2.2)2 (0.9)
Smoking0.371
Never-smoker89 (48.1)123 (53.9)
Ex-smoker42 (22.7)40 (17.5)
Current smoker54 (29.2)65 (28.5)
Alcohol0.556
None82 (44.3)112 (49.1)
< 1 drink/d42 (22.7)51 (22.4)
≥ 1 drink/d61 (33.0)65 (28.5)
Aspirin use50 (27.0)39 (17.1)0.015
Insulin use17 (9.2)27 (16.2)0.035
Sulfonylurea use116 (62.7)153 (67.1)0.350
Thiazolidinedione use18 (9.7)12 (5.3)0.082
CEA in ng/mL, median (range)4.7 (0.2-9100.0)6.4 (0.1-5946.0)0.359
HbA1c, mean ± SD8.7 ± 16.77.3 ± 1.40.349
Glucose in mg/dL, AC ± SD143.8 ± 46.1132.4 ± 41.10.012
Cholesterol in mg/dL, total ± SD167.9 ± 47.8164.6 ± 39.60.483
Tumor stage0.110
III136 (73.5)151 (66.2)
IV49 (26.5)77 (33.8)
Tumor site0.940
Colon106 (57.9)130 (58.3)
Rectum77 (42.1)93 (41.7)
Histology0.001
Adenocarcinoma177 (97.8)199 (89.6)
Mucinous carcinoma4 (2.2)23 (10.4)
Differentiation0.155
Well differentiated13 (7.4)16 (7.8)
Moderately differentiated148 (84.6)174 (84.5)
Poorly differentiated14 (8.0)12 (5.8)
Resection margin +3 (1.7)1 (0.6)0.371
Lymphovascular invasion56 (25.9)76 (50.0)0.031
MSI state0.670
MSi78 (89.7)68 (90.7)
MSI-low6 (6.9)6 (8.0)
MSI-high3 (3.4)1 (1.3)
Treatment modality0.160
Resection only9 (4.9)20 (8.8)
Resection + adjuvant chemotherapy115 (63.2)126 (55.3)
Resection + chemoradiotherapy22 (12.1)24 (10.5)
Neoadjuvant chemotherapy + resection17 (9.3)17 (7.5)
Chemotherapy only17 (9.3)35 (15.4)
Conservative care2 (1.1)6 (2.6)
Table 2 Multivariate logistic regression analysis for colorectal cancer-specific mortality
HR95%CIP value
Age at diagnosis of ≥ 50 or < 500.7230.312-1.6750.449
Sex, female or male0.5920.357-0.9820.042
BMI of ≥ 25 or < 250.5140.287-0.9190.025
Smoking history as yes or no0.6810.359-1.2910.239
Aspirin use as yes or no0.8020.455-1.4150.446
Metformin treatment duration in mo0.9850.974-0.9970.012
Sulfonylurea use as yes or no1.3000.798-2.1200.292
Insulin use as yes or no1.0410.511-2.1210.912
Stage IV or III8.4015.285-13.355< 0.001
Site as rectum or colon0.8230.521-1.2990.403
Pathology0.8010.238-2.7010.721
Diabetes duration0.9680.935-1.0010.059
HbA1C1.0151.004-1.0270.010
Table 3 Interaction analysis of metformin and relevant factors on colorectal cancer-specific mortality
HR95%CIP value
Metformin-Sex0.3690.155-0.8810.025
Metformin-BMI1.0000.974-1.0260.972
Metformin-Site0.9410.441-2.0060.875
Metformin-HbA1c0.9990.926-1.0780.979