| Pre-treatment variables that may be associated with treatment preference and/or primary outcomes |
| Range of gastrectomy |
Total gastrectomy, proximal gastrectomy |
1 |
| No. of comorbidities |
Including a quadratic term for non-linearity |
2 |
| Lung function |
Abnormal, normal |
1 |
| Tumor size via preoperative assessment, long diameter |
Including a quadratic term for non-linearity |
2 |
| Tumor size via preoperative assessment, short diameter |
Including a quadratic term for non-linearity |
2 |
| Age (year) |
<45, 45−55, 56−65, 66−75, >75 |
4 |
| cT stage |
2, 3, 4a |
2 |
| cN stage |
0, 1, 2, 3 |
3 |
| Body mass index |
Underweight, normal, overweight, obese |
3 |
| Preoperative hemoglobin |
Including a quadratic term for non-linearity |
2 |
| No. of lung comorbidities |
Including a quadratic term for non-linearity |
2 |
| History of smoking and smoking cessation |
Non-quitted, quitted, non-smokers |
2 |
| Length of esophageal invasion |
Including a quadratic term for non-linearity |
2 |
| Timing of surgery |
Morning, afternoon, evening |
2 |
| History of cardiac diseases |
Yes, no |
1 |
| Siewert type |
I, II |
1 |
| CEA |
Including a quadratic term for non-linearity |
2 |
| CA199 |
Including a quadratic term for non-linearity |
2 |
| CA125 |
Including a quadratic term for non-linearity |
2 |
| Geographical location |
East and central west, Southwest and northwest, North and northeast |
2 |
| Hospital type |
Cancer specialized, general |
1 |
| Additional pre-treatment variables that may be associated with primary outcomes alone |
| Differentiation |
Well, moderate, poor |
2 |
| Lauren type |
Diffused, mixed, intestinal |
2 |
| Gender |
Male, female |
1 |
