Table 1.
Patient characteristics according to the use of PPIs
| Characteristic | PPI use <20% (n = 433), n (%) | PPI use ≥20% (n = 49), n (%) | p value |
|---|---|---|---|
| Age (years) | .46 | ||
| <65 | 305 (70.4) | 32 (65.3) | |
| ≥65 | 128 (29.6) | 17 (34.7) | |
| Median (IQR) | 59 (51–66) | 60 (48–69) | .72 |
| Sex | .31 | ||
| Men | 262 (60.5) | 26 (53.1) | |
| Women | 171 (39.5) | 23 (46.9) | |
| Country | .37 | ||
| Japan | 103 (23.8) | 15 (30.6) | |
| South Korea | 203 (46.9) | 18 (36.7) | |
| China | 127 (29.3) | 16 (32.7) | |
| ECOG performance status | >.99 | ||
| 0−1 | 430 (99.3) | 49 (100.0) | |
| 2 | 3 (0.7) | 0 (0.0) | |
| Stage at diagnosis | .81 | ||
| Synchronous metastasis | 261 (60.3) | 31 (63.3) | |
| Metachronous metastasis | 170 (39.3) | 18 (36.7) | |
| Unknown | 2 (0.5) | 0 (0.0) | |
| Number of metastatic sites | .10 | ||
| 1 | 157 (36.3) | 12 (24.5) | |
| >1 | 276 (63.7) | 37 (75.5) | |
| Liver metastasis: Yes | 260 (60.0) | 28 (57.1) | .70 |
| Liver‐limited metastasis: Yes | 75 (17.3) | 6 (12.2) | .37 |
| Previous use of oxaliplatin: Yes | 426 (98.4) | 49 (100.0) | >.99 |
| Postoperative adjuvant chemotherapy: Yes | 112 (25.9) | 15 (30.6) | .48 |
| Previous use of anti‐EGFR antibody therapy: Yes | 58 (13.4) | 7 (14.3) | .86 |
| Concomitant bevacizumab in this study: Yes | 345 (79.7) | 38 (77.6) | .73 |
| Alkaline phosphatase | .12 | ||
| Normal | 266 (61.4) | 36 (73.5) | |
| Abnormal | 144 (33.3) | 13 (26.5) | |
| Unknown | 23 (5.3) | 0 (0.0) | |
| UGT1A1 polymorphism | .12 | ||
| Wild type | 217 (50.1) | 19 (38.8) | |
| Single heterozygote | 182 (42.0) | 28 (57.1) | |
| Double heterozygotes or homozygotes | 34 (7.9) | 2 (4.1) | |
| KRAS status | .29 | ||
| Wild type | 188 (43.4) | 19 (38.8) | |
| Mutant | 131 (30.3) | 12 (24.5) | |
| Unknown | 114 (26.3) | 18 (36.7) | |
| Treatment | .83 | ||
| FOLFIRI | 219 (50.6) | 24 (49.0) | |
| mXELIRI | 214 (49.4) | 25 (51.0) |
p value was calculated by chi‐squared test, Fisher's exact test, or Wilcoxon rank‐sum test.
Abbreviations: ECOG, Eastern Cooperative Oncology Group; EGFR, epidermal growth factor receptor; FOLFIRI, leucovorin, fluorouracil, and irinotecan; mXELIRI, modified capecitabine plus irinotecan; PPI, proton pump inhibitor; IQR, interquartile range; UGT1A1, UDP‐glucuronosyltransferase 1A1.