Aims
To identify factors associated with adequate bowel cleansing prior to colonoscopy.
Methods
A retrospective observational study was conducted including all colonoscopies performed at our center during the first quarter of 2025. Adult patients without prior gastrointestinal resection were included and categorized according to the Boston Bowel Preparation Scale (adequate: ≥6; poor: <6). Clinical variables analyzed included comorbidities (ASA classification), regular medication, BMI, abdominal circumference, alcohol consumption, physical exercise on the day of the procedure, bowel habits, use of laxatives or prokinetics, fasting hours for solids and liquids, timing of bowel preparation doses, duration of low-residue and liquid diets, presence of diverticula, and prior abdominal surgery.
Results
A total of 206 patients (110 women, 96 men; mean age 57.5 years) were analyzed. Adequate bowel cleansing was achieved in 198 patients (96.1%), while 8 (3.9%) had suboptimal preparation. Statistically significant differences between groups were found for physical exercise on the day of the procedure, comorbidity level (ASA classification), fasting duration on a liquid diet, and the timing of completion of the last bowel preparation dose.
Comparative Table of Variables Between Groups With Good/Poor Bowel Preparation. Statistical Analysis Table Between Groups With Good and Poor Bowel Preparation.
|
Variable |
Total Sample (n=206) |
Good Preparation (Boston ≥ 6 points, n=198) |
Poor Preparation (Boston < 6 points, n=8) |
p-value (<0.05) |
|
Sex (n) |
Women: 110Male: 96 |
Women: 103Male: 95 |
Women: 7Male: 1 |
0.071 |
|
Median age (years) |
57.5 (W: 57 / M: 59) |
62 |
56.5 |
0.796 |
|
Median BMI |
25.8 (W: 25 / M: 26.1) |
25.95 |
34.7 |
0.535 |
|
Median weight (kg) |
72 (W: 65 / M: 79) |
68.5 |
96.5 |
0.673 |
|
Median abdominal circumference (cm) |
95 |
86.5 |
136 |
0.943 |
|
Diabetes Mellitus (DM) |
23 |
21 |
2 |
0.247 |
|
Hypothyroidism |
22 |
21 |
1 |
1.000 |
|
Hyperthyroidism |
1 |
1 |
0 |
1.000 |
|
Neurological disorders |
6 |
6 |
0 |
1.000 |
|
Alcohol consumption (n) |
None: 98Occasional: 81Daily: 27 |
None: 94Occasional: 79Daily: 25 |
None: 4Occasional: 2Daily: 2 |
0.222 |
|
Bowel habit |
<2/week: 42–5/week: 41Daily: 134>1/day: 27 |
<2/week: 42–5/week: 40Daily: 127>1/day: 27 |
<2/week: 02–5/week: 1Daily: 7>1/day: 0 |
0.917 |
|
Use of laxatives |
None: 187Macrogol: 5Soluble fiber: 4Others: 10 |
None: 180Macrogol: 5Soluble fiber: 4Others: 9 |
None: 7Macrogol: 0Soluble fiber: 0Others: 1 |
1.000 |
|
Use of prokinetics |
None: 205Levosulpiride: 1Dopamine antagonist: 0Metoclopramide: 0Others: 0 |
None: 197Levosulpiride: 1Dopamine antagonist: 0Metoclopramide: 0Others: 0 |
None: 8Levosulpiride: 0Dopamine antagonist: 0Metoclopramide: 0Others: 0 |
0.860 |
|
Use of enemas |
No: 206Yes: 0 |
No: 198Yes: 0 |
No: 8Yes: 0 |
--- |
|
Opioid consumption |
No: 196Yes: 10 |
No: 188Yes: 10 |
No: 8Yes: 0 |
0.520 |
|
Previous abdominal surgeries |
None: 133Cholecystectomy: 13Abdomino-inguinal hernias: 7Gynecologic: 28Urologic: 1Others: 24 |
None: 129Cholecystectomy: 12Abdomino-inguinal hernias: 7Gynecologic: 27Urologic: 1Others: 22 |
None: 4Cholecystectomy: 1Abdomino-inguinal hernias: 0Gynecologic: 1Urologic: 0Others: 2 |
0.458 |
|
ASA classification |
ASA I–II: 189ASA III–IV: 17 |
ASA I–II: 184ASA III–IV: 14 |
ASA I–II: 5ASA III–IV: 3 |
ASA I-II: 0.765 ASA III/IV: 0.040
|
|
Physical activity on the day |
None: 186Walking: 18Aerobic: 2 |
None: 179Walking: 17Aerobic: 1 |
None: 5Walking: 1Aerobic: 1 |
0.008 |
|
Diverticulosis |
No: 131Yes: 75 |
No: 125Yes: 73 |
No: 6Yes: 2 |
1.000 |
|
Evacuating solution |
Pleinvue: 160Bohm: 9Citrafleet: 37 |
Pleinvue: 152Bohm: 9Citrafleet: 37 |
Pleinvue: 8Bohm: 0Citrafleet: 0 |
0.525 |
|
Liquid for solution |
Water: 205Juice: 1Others: 0 |
Water: 197Juice: 1Others: 0 |
Water: 8Juice: 0Others: 0 |
0.789 |
|
Median fasting time (liquids, h) |
8 |
9 |
11.5 |
0.0276 |
|
Median fasting time (solids, h) |
28 |
29 |
24 |
0.9007 |
|
Median days on residue-free diet |
3 |
2.5 |
2 |
0.312 |
|
Median days on liquid diet |
1 |
1 |
1 |
0.790 |
|
Median time of first sachet completion (h) |
13.5 |
18 |
12.5 |
0.275 |
|
Median time of second sachet completion (h) |
9.5 |
10 |
12 |
0.0182 |
|
Procedure schedule |
Morning: 25Afternoon: 181 |
Morning: 22Afternoon: 176 |
Morning: 3Afternoon: 5 |
--- |
|
% of sample |
100% |
96.12% |
3.88% |
--- |
Conclusions
Physical exercise, lower comorbidity, and a shorter interval between bowel preparation and colonoscopy appear to be key factors associated with adequate bowel cleansing. Optimizing these elements may improve colonoscopy quality and diagnostic yield.