Baseline characteristics of the two study groups
| Observation (n=29) | Control (n=91) | P value | |
| Gender, n (%) | |||
| Male | 16 (55.0) | 55 (60.0) | 0.667 |
| Female | 13 (45.0) | 36 (40.0) | |
| Age (years) | 39.24±11.63 | 42.95±12.76 | 0.167 |
| Smoking history, n (%) | 11 (37.9) | 48 (52.7) | 0.165 |
| Drinking history, n (%) | 13 (44.8) | 49 (53.8) | 0.397 |
| Complications, n (%) | |||
| Diabetes | 2 (6.9) | 8 (8.8) | 1.000 |
| Hypertension | 4 (13.8) | 15 (16.5) | 1.000 |
| Renal insufficiency | 2 (6.9) | 7 (7.7) | 1.000 |
| Chronic obstructive pulmonary disease | 3 (12.6) | 12 (13.2) | 1.000 |
| Lesion range, n (%) | |||
| E1 | 10 (34.5) | 25 (27.5) | 0.282 |
| E2 | 6 (20.7) | 34 (37.4) | |
| E3 | 13 (44.8) | 32 (35.1) | |
| Modified Mayo Scoring | 6.79±1.42 | 7.44±1.35 | 0.043 |
E1: endoscopic lesion was limited to the rectum; E2: endoscopic lesion involved the left colon; E3: splenic flexure was engaged near the whole colon.