Observational Study
Copyright ©The Author(s) 2021.
World J Gastrointest Endosc. Dec 16, 2021; 13(12): 659-672
Published online Dec 16, 2021. doi: 10.4253/wjge.v13.i12.659
Table 1 Demographic and clinical features of the study population, n (%)
Characteristics
High volume (n = 871)
Low volume (n = 944)
P value1
Age61.2 ± 14.360.1 ± 14.60.092
Male sex463 (53.2)448 (47.5)0.0153
Split-dose389 (44.7)361 (38.2)0.0063
High-definition colonoscope296 (33.9)310 (32.8)0.605
Indication
Symptoms538 (61.8)563 (59.6)
Surveillance< 0.0013
Post polypectomy134 (15.4)154 (16.3)
Post colonic resection for CRC73 (8.4)73 (7.7)
Positive FBT94 (10.8)57 (6.1)
IBD32 (3.6)97 (10.3)
BMI, mean ± SD225.5 ± 4.325.0 ± 4.00.0153
Previous abdominal surgery98 (11.3)96 (10.2)0.456
Constipation66 (7.6)86 (9.1)0.239
Comorbidities
Heart disease 90 (10.3)65 (6.9)0.0093
Diabetes72 (8.3)65 (6.9)0.266
Stroke/dementia19 (2.2)25 (2.6)0.518
Severe CKD21 (2.4)15 (1.6)0.209
Cirrhosis12 (1.4)13 (1.4)0.999
GERD192 (22.0)219 (23.2)0.557
Waiting time > 1 mo485 (55.7)570 (60.4)0.0903
Non-adherence to low fiber diet91 (10.5)112 (11.9)0.329
Lives alone2123 (14.8)149 (16.3)0.395
Low instruction2157 (19.6)122 (14.1)0.0023
1P value degrees of freedom = 1, except for age (1814), indication (4) and body mass index (BMI) (1726).
2BMI available for 1727 patients; information about living alone available for 1747 patients; instruction level available for 1662 patients.
3Significant different.
CRC: Colorectal cancer; FBT: Fecal blood test; IBD: Inflammatory bowel disease; BMI: Body mass index; CKD: Chronic kidney disease; GERD: Gastroesophageal reflux disease.
Table 2 Clinical outcomes according to quality of preparation, n (%)
Outcome
Adequate preparation (n = 1595)
Inadequate preparation (n = 220)
OR (95%CI)
P value1
Complete examination1590 (99.7)203 (92.3)26.63 (9.72-72.96)< 0.0012
PDR476 (29.8)44 (20.1)1.69 (1.20-2.40)0.0032
ADR347 (21.8)34 (15.5)1.52 (1.04-2.23)0.0332
AADR82 (5.1)9(4.1)1.27 (0.63-2.57)0.505
Cancer27 (1.7)7 (3.2)0.52 (0.23-1.22)0.133
SDR26 (1.6)2 (0.9)1.81 (0.43-7.66)0.423
1P value degrees of freedom = 1.
2Significant different.
OR: Odds ratio; PDR: Polyp detection rate; ADR: Adenoma detection rate; AADR: Advanced adenoma detection rate; SDR: Sessile lesion detection rate.
Table 3 Clinical outcomes according to volume of bowel preparation, n (%)
Outcome
High volume (n = 871)
Low volume (n = 944)
OR (95%CI)
P value1
Adjusted2 OR (95%CI)
P value2
PDR283 (32.5)237 (25.1)1.43 (1.17–1.76)< 0.00131.32 (1.07–1.63)0.0113
ADR210 (24.1)171 (18.1)1.44 (1.14–1.80)0.00231.29 (1.02–1.63)0.0383
AADR56 (6.4)35 (3.7)1.79 (1.16–2.75)0.00931.51 (0.97–2.35)0.069
Cancer19 (2.2)15 (1.6)1.38 (0.70–2.74)0.354
SDR16 (1.8)12 (1.3)1.45 (0.68–3.09)0.331
1P value degrees of freedom = 1.
2Adjustment for age (as a continuous variable), sex and indications for colonoscopy; P value degrees of freedom = 7.
3Significant different.
OR: Odds ratio; PDR: Polyp detection rate; ADR: Adenoma detection rate; AADR: Advanced adenoma detection rate; SDR: Sessile lesion detection rate.
Table 4 Clinical outcomes according to volume of bowel preparation, high-definition colonoscopes, n (%)
Outcome
High volume (n = 296)
Low volume (n = 310)
OR (95% CI)
P value1
PDR97 (32.7)93 (30.0)1.13 (0.81–1.60)0.462
ADR70 (23.6)74 (23.9)0.99 (0.68–1.44)0.948
AADR21 (7.1)17 (5.5)1.31 (0.68–2.54)0.415
Cancer5 (1.7)5 (1.6)1.05 (0.30–3.66)0.941
SDR4 (1.4)4 (1.3)1.05 (0.26–4.23)0.947
1P value degrees of freedom = 1.
OR: Odds ratio; PDR: Polyp detection rate; ADR: Adenoma detection rate; AADR: Advanced adenoma detection rate; SDR: Sessile lesion detection rate.
Table 5 Clinical outcomes according to volume of bowel preparation, standard-definition colonoscopes, n (%)
Outcome
High volume (n = 575)
Low volume (n = 634)
OR (95%CI)
P value1
Adjusted2 OR (95%CI)
P value2
PDR186 (32.3)144 (22.7)1.63 (1.26–2.10)< 0.00131.59 (1.22–2.08)< 0.0013
ADR140 (24.3)97 (15.3)1.78 (1.34–2.38)< 0.00131.71 (1.26–2.30)< 0.0013
AADR35 (6.1)18 (2.8)2.23 (1.24–3.96)0.00731.97 (1.09–3.56)0.0253
Cancer14 (2.4)10 (1.6)1.56 (0.69–3.53)0.289
SDR12 (2.1)8 (1.3)1.67 (0.68–4.11)0.266
1P value degrees of freedom = 1.
2Adjustment for age (as a continuous variable), sex and indications for colonoscopy; P value degrees of freedom = 7.
3Significant different.
OR: Odds ratio; PDR: Polyp detection rate; ADR: Adenoma detection rate; AADR: Advanced adenoma detection rate; SDR: Sessile lesion detection rate.
Table 6 Clinical outcomes of high and low-volume preparations according to different schedules, n (%)
Outcome
High volume day before (n = 482)
High volume split-dose (n = 389)
P value1
Low volume day before (n = 583)
Low volume split-dose (n = 361)
P value1
PDR149 (30.9)134 (34.4)0.277145 (24.9)92 (25.5)0.833
ADR108 (22.4)102 (26.2)0.191103 (17.7)68 (18.8)0.650
AADR30 (6.2)26 (6.7)0.78320 (3.4)15 (4.2)0.567
Cancer11 (2.3)8 (2.1)0.8276 (1.0)9 (2.5)0.088
SDR5 (1.0)11 (2.8)0.0508 (1.4)4 (1.1)1.000
1P value degrees of freedom = 1.
PDR: Polyp detection rate; ADR: Adenoma detection rate; AADR: Advanced adenoma detection rate; SDR: Sessile lesion detection rate.
Table 7 Self-reported tolerability of bowel preparations according to volume, n (%)
Total (n = 1815)
High volume (n = 871)
Low volume (n = 944)
P value1
Global tolerance, VAS score2, median (interquartile range)7 (5-9)7 (5-9)7 (5-9)0.627
Incomplete preparation (< 75% of PEG assumed)116 (6.6)67 (7.9)49 (5.4)0.0323
Any symptom during preparation860 (47.4)369 (42.4)491 (52)< 0.0013
Bloating363 (20)183 (21)180 (19.1)0.301
Nausea480 (26.5)187 (21.5)293 (31)< 0.0013
Vomiting174 (9.6)55 (6.3)119 (12.6)< 0.0013
Abdominal pain281 (15.5)104 (11.9)177 (18.8)< 0.0013
1P value degrees of freedom = 1.
2Visual analogue scale: 0 absolutely non-tolerated, 10 perfectly tolerated. Data available for 1772 patients.
3Significant different.
VAS: Visual analogue scale; PEG: Polyethylene glycol.
Table 8 Tolerability of high and low-volume preparations according to different schedules, n (%)
High volume one-day (n = 482)
High volume split dose (n = 389)
P value1
Low volume one-day (n = 583)
Low volume split dose (n = 361)
P value1
Global tolerance, VAS score2, median (interquartile range)7 (5-8)7 (5-9)0.00637 (5-9)7 (5-9)0.033
Incomplete preparation 37 (7.9)30 (7.9)0.99431 (5.5)18 (5.2)0.840
Any symptom during preparation211 (43.8)158 (40.6)0.384324 (55.6)167 (46.3)0.0053
Bloating103 (21.4)80 (20.6)0.772126 (21.6)54 (14.9)0.0113
Nausea112 (23.2)75 (19.3)0.158196 (33.6)97 (26.9)0.0293
Vomiting33 (6.9)22 (5.7)0.47373 (12.5)46 (12.7)0.921
Abdominal pain54 (11.2)50 (12.9)0.455105 (18.0)72 (19.9)0.459
1P value degrees of freedom = 1.
2Visual Analogue Scale: 0 absolutely non-tolerated, 10 perfectly tolerated. Data available for 1772 patients.
3Significant different.
VAS: Visual analogue scale.