Table 2

Characteristics of the study population at index colonoscopy (n=2997)

All patients (n=2997)
Characteristics of patients with adenoma
Male (n, %)1713 (57.2)
Age (mean, SD)58.6 (9.0)
Active guideline (n, %)
 June 1998–20012303 (76.8)
 2002694 (23.2)
Hospital type (n, %)
 Non-academic2097 (70.0)
 Academic900 (30.0)
Geographical area (n, %)
 High density population area1641 (54.8)
 Low density population area1356 (45.2)
Active follow-up system (n, %)
 No1975 (65.9)
 Yes1022 (34.1)
Adenoma characteristics
No. of adenomas (mean, SD)*1.5 (0.9)
No. patients with (n, %)
 multiple (≥3) adenomas*347 (11.6)
 Any adenoma with size ≥10 mm†‡1127 (37.6)
 Any adenoma with high-grade dysplasia†368 (12.3)
 Any villous adenoma†150 (5.0)
 Any proximal adenoma†900 (30.0)
Index endoscopy characteristics
Intended sigmoidoscopy (n, %)306 (10.2)
Reach endoscope (n, %)†
 Complete colonoscopy§2538 (84.7)
 Proximal colon293 (9.8)
 Distal colon166 (5.5)
Bowel preparation (n, %)†
 Good¶2723 (90.9)
 Moderate221 (7.4)
 Insufficient52 (1.7)
  • *Variable truncated to 5+ adenomas, and imputed for missing values.

  • †Weighted average (data from 433 patients without surveillance weighted to the 1093 patients without surveillance).

  • ‡Size ≥10 mm either as reported by an endoscopist or a pathologist.

  • §58 missings assumed to have a complete colonoscopy (in 2337 (1904+433) patients with data).

  • ¶1598 missings assumed to have a good bowel preparation (in 2337 (1904+433) patients with data).