Table 1.
Association between metformin use and OS and PFS, according to the characteristics of mCRC patients with T2DM, SYUCC 2004 to 2016
| Characteristics* | OS | Pinteraction | PFS | Pinteraction | ||
| No. of events† | HR (95% CI) | No. of events‡ | HR (95% CI) | |||
| Metformin use vs. nonmetformin use | 51:68 | 0.746 (0.496, 1.121) | 55:60 | 0.737 (0.501, 1.086) | ||
| Metformin use vs. nonmetformin use after stratifying with | ||||||
| Sex | 0.321 | 0.493 | ||||
| Male | 37:44 | 0.673 (0.401, 1.131) | 42:43 | 0.732 (0.468, 1.146) | ||
| Female | 14:15 | 0.944 (0.385, 2.318) | 13:17 | 0.697 (0.318, 1.529) | ||
| Age at diagnosis, y | 0.697 | 0.054 | ||||
| <60 | 21:19 | 0.869 (0.411, 1.715) | 23:22 | 1.074 (0.580, 1.990) | ||
| ≥60 | 30:40 | 0.596 (0.348, 0.988) | 32:38 | 0.562 (0.339, 0.930) | ||
| BMI, kg/m2 | 0.867 | 0.430 | ||||
| Normal (18.5∼23.0) | 33:33 | 0.582 (0.334, 1.013) | 37:33 | 0.884 (0.542, 1.442) | ||
| Pre & obese (>23.0) | 18:26 | 0.702 (0.357, 1.382) | 18:27 | 0.555 (0.287, 1.073) | ||
| Primary site | 0.444 | 0.426 | ||||
| Right colon | 10:17 | 0.729 (0.294, 1.807) | 8:15 | 0.622 (0.255, 1.517) | ||
| Left colon | 21:24 | 0.982 (0.527, 1.830) | 22:29 | 0.823 (0.451, 1.500) | ||
| Rectum | 20:18 | 0.475 (0.215, 1.051) | 25:16 | 0.544 (0.282, 1.048) | ||
| Metastatic site | — | — | ||||
| Liver | 23:25 | 1.151 (0.563, 2.354) | 23:29 | 0.949 (0.481, 1.871) | ||
| Other organs | 9:4 | — | 10:4 | — | ||
| Distant lymph nodes | 7:5 | — | 4:2 | — | ||
| Multiple sites | 10:12 | 1.008 (0.346, 2.939) | 14:16 | 0.818 (0.329, 2.031) | ||
| Peritoneum | 2:13 | — | 4:9 | — | ||
| Pathological grading | — | — | ||||
| Well-differentiated | 1:0 | — | 0:2 | — | ||
| Moderately differentiated | 33:38 | 0.676 (0.407, 1.125) | 32:35 | 0.644 (0.384, 1.080) | ||
| Poorly & undifferentiated | 17:21 | 0.629 (0.245, 1.616) | 23:23 | 0.811 (0.445, 1.477) | ||
| KRAS genotype | <0.001 | 0.020 | ||||
| Wild type | 32:37 | 1.487 (0.844, 2.620) | 32:39 | 1.194 (0.720, 1.979) | ||
| Mutation | 19:22 | 0.272 (0.120, 0.617) | 23:21 | 0.405 (0.212, 0.774) | ||
Pinteraction, P value for the interaction test. “—” indicates the variable is excluded because of fewer than five observations in this category.
*
Each characteristic was stratified by age at diagnosis and adjusted for the other variables listed above.
†
The number of cases of death after diagnosis as mCRC.
‡
The number of cases dead or getting worse during first-line chemotherapy.