TABLE 1.
Baseline characteristics of patients
| Variables | MET group (n = 89) | NMET group (n = 377) | p‐value |
|---|---|---|---|
| Median age at ICI treatment | 67.3 ± 10.1 | 65.3 ± 11.0 | 0.179 |
| Sex | |||
| Male | 72 (80.9%) | 275 (72.9%) | 0.122 |
| Female | 17 (19.1%) | 102 (27.1%) | |
| Smoking history | |||
| Smoker (current or ex‐smoker) | 69 (77.5%) | 254 (67.4%) | 0.110 |
| Never smoker | 20 (22.5%) | 116 (30.8%) | |
| NA | 0 (0%) | 7 (1.8%) | |
| ECOG PS | |||
| 0–1 | 50 (56.2%) | 201 (53.3%) | 0.498 |
| ≥2 | 34 (38.2%) | 140 (37.1%) | |
| NA | 5 (5.6%) | 36 (9.5%) | |
| Previous treatment | |||
| Chemotherapy | |||
| Yes | 82 (92.1%) | 350 (92.8%) | 0.818 |
| No | 7 (7.9%) | 27 (7.2%) | |
| TKI | |||
| Yes | 17 (19.1%) | 96 (25.5%) | 0.208 |
| No | 72 (80.9%) | 281 (74.5%) | |
| PD‐L1 status | |||
| <1% | 24 (27.0%) | 114 (30.2%) | 0.334 |
| 1–49% | 25 (28.1%) | 89 (23.6%) | |
| ≥50 | 35 (39.3%) | 132 (35.0%) | |
| NA | 5 (5.6%) | 42 (11.2%) | |
| ICIs | |||
| PD‐1 Ab | 58 (65.2%) | 249 (66.0%) | 0.901 |
| PD‐L1 Ab | 31 (34.8%) | 128 (34.0%) | |
| ICI line | |||
| First‐line | 6 (6.7%) | 41 (10.9%) | 0.473 |
| Second‐line | 51 (57.3%) | 199 (52.8%) | |
| Third−/later‐line | 32 (36.0%) | 137 (36.3%) | |
| Median cycles of ICI | 8.9 ± 10.1 | 8.9 ± 10.8 | 0.654 |
| Driver mutation | |||
| (EGFR or ALK) | |||
| Yes | 17 (19.1%) | 97 (25.7%) | 0.191 |
| No | 72 (80.9%) | 280 (74.3%) | |
| Mean number of metastatic sites before starting therapy | 1.7 ± 1.1 | 1.69 ± 0.9 | 0.468 |
| Brain metastasis | |||
| Yes | 19 (21.3%) | 92 (24.4%) | 0.543 |
| Bo | 70 (78.7%) | 285 (75.6%) |
Abbreviations: Ab, antibody; ALK, anaplastic lymphoma kinase; ECOG PS, Eastern Cooperative Oncology Group performance status; EGFR, epidermal growth factor receptor; ICI, immune checkpoint inhibitor; MET group, concomitant administration of metformin and DPP4 inhibitor (metformin or combination of metformin and DPP4 inhibitor); NA, not available; NMET group, without concomitant administration of metformin and DPP4 inhibitor; PD‐1, programmed cell death protein 1; PD‐L1, programmed death‐ligand 1; TKI, tyrosine kinase inhibitor.