Table 1.
Summary of meta-analysis regarding bowel preparation.
| Reference | No. studies | Study type | Aim | Comparison group | Results | |
|---|---|---|---|---|---|---|
| Diet | Nguyen et al. (9) | 9 | RCT | Outcomes on patients undergoing colonoscopy | LRD vs. CLD | Adequate bowel preparations: OR 1.21; 95% CI, 0.64–2.28 |
| Willingness to repeat preparation: OR 1.86; 95% CI, 1.34–2.59 |
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| Tolerability: OR 1,92; 95% CI, 1.36–2.7 | ||||||
| AEs: OR 0.88; 95% CI, 0.58–1.35 | ||||||
| Song et al. (10) | 7 | RCT | Efficacy in bowel preparation | LRD vs. CLD | Excellent or good bowel preparation: RR, 1.01; 95% CI, 0.91–1.13 |
|
| Tolerance RR, 1.06; 95% CI, 1.02–1.11 | ||||||
| Tended to repeat the same preparation RR, 1.17; 95% CI, 1.09–1.26 |
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| Compliance: RR 0.97; 95% CI, 0.87–1.08 | ||||||
| AEs: RR 0.99; 95% CI, 0.88–1.12; P = 0.92 | ||||||
| Split dose regimen | Bucci et al. (13) | 29 | RCT | 1°: efficacy of colon cleansing, 2°: to assess the runaway time, rate of compliance |
Split dose vs. non-split dose regimen | Adequate preparation raw rate difference: RR 0,22; 95% CI, 0.16-0.27 |
| The heterogeneity was caused by: the runway time (the longer, the worse the cleansing), type of diet, male sex, use of polyethylene glycol 4 L, and the Jadad score | ||||||
| Martel et al. (14) | 47 | RCT | 1°: bowel cleanliness; 2°: willingness-to-repeat, ADR or PDR, AEs, complications |
Split dose vs. non-split dose regimen | Better colon cleansing: OR, 2.51; 95% CI, 1.86–3.39 |
|
| Willing to repeat: OR, 1.90; 95% CI, 1.05–3.46 |
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| PDR: OR 0.93; 95% CI, 0.41–2.13 | ||||||
| ADR: OR 1.52, 95% CI, 0.69–3.32 | ||||||
| Avalos et al. (15) | 15 | RCT | 1°: bowel preparation quality; 2°: willingness to repeat, tolerability/compliance, ADR, AEs |
Same day vs. split dose | High quality bowel preparation: RR 0.95; 95% CI, 0.90–1.00 | |
| ADR: RR 0.97; 95% CI, 0.79–1.20 | ||||||
| Willingness to repeat: RR 1.14, 95% CI, 0.96–1.36 | ||||||
| Tolerability: RR 1.00; 95% CI, 0.96–1.04 | ||||||
| Bloating: RR 0.68; 95% CI, 0.40–0.94 | ||||||
| Cheng et al. (16) | 14 | RCT | 1°: bowel cleanliness (adequate or satisfactory), 2°: cecal intubation rate, ADR, willingness to repeat, AEs |
Same day vs. Split-dose regimen | Bowel cleanliness: OR 0.92; 95% CI, 0.62–1,36 | |
| Cecal intubation rate: OR 0.87, 95% CI, 0.49–1.54 | ||||||
| ADR: OR 0.87; 95% CI, 0.67–1.13 | ||||||
| Willingness to repeat: OR 1.08; 95% CI, 0.45–2.61 | ||||||
| AEs: OR 0.86; 95% CI 0.53–1.39 | ||||||
| Adjuvants | Restellini et al. (17) | 77 | RCT | 1°: bowel cleanliness (adequate), 2° : willingness to repeat, ADR |
All preparations + adjuvants vs. all preparations without adjuvants | Adequate bowel preparation: OR 1.35; 95% CI, 1.02–1.78 |
| Willingness to repeat proportion OR 1.40; 95%; CI, 0.91–2.15 |
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| ADR: OR 1.03; 95%; CI, 0.86–1.23 | ||||||
| Education tools | Guo et al. (18) | 8 | RCT | 1°: rate of adequate bowel preparation, cecal intubation rate, PDR, AEs, willingness to repeat | Enhanced instructions vs. regular instructions | Adequate bowel preparation: OR 2.35; 95% CI, 1.65–3.35 |
| Cecal intubation rate: OR 2.77; 95% CI, 1.73–4.42 | ||||||
| PDR: OR 1.25;95% CI, 0.93–1.68 | ||||||
| Willing to repeat: OR 1.91; 95% CI, 1.20–3.04 | ||||||
| AEs: OR 0.76; 95% CI, 0.54–1.07 | ||||||
| Chang et al. (19) | 9 | RCT | 1°: quality of bowel preparation, 2°: PDR and need for repeat colonoscopy | Educational intervention vs. control group | Adequate bowel preparation: RR 1.22; 95 % CI 1.10–1.36 | |
| PDR: RR1.14; 95 % CI 0.87–1.51 | ||||||
| Need for repeat colonoscopy: RR 0.52; 95 %CI 0.25–1.04 |
RCT, randomized clinical trial; LRD, low-residue diet; CLD, clear liquid diet; AEs, adverse events, PDR, polyp detection rate.