One-day versus three-day low-residue diet bowel preparation regimens before colonoscopy: a meta-analysis of randomized controlled trials.

BACKGROUND AND AIM: Although studies have shown that the quality of bowel preparation with low-residue diet (LRD) is as effective as that of clear fluid diet (CLD), there is currently no consensus on how long an LRD should last. The aim of this study was to compare a 1-day versus 3-day LRD on bowel preparation before colonoscopy. METHODS: A systematic review search was conducted in MEDLINE/PubMed, EMBASE, Web of Science, and Cochrane database from inception to April 2023. We identified randomized controlled trials (RCTs) that compared 1-day with 3-day LRD bowel cleansing regiments for patients undergoing colonoscopy. The rate of adequate bowel preparation, polyp detection rate, adenoma detection rate, tolerability, willingness to repeat preparation, and adverse events were estimated using odds ratios (OR) and 95% confidence interval (CI). We also performed meta-analysis to identify risk factors and predictors of inadequate preparation. RESULTS: Four studies published between 2019 and 2023 with 1927 participants were included. The present meta-analysis suggested that 1-day LRD was comparable with 3-day LRD for adequate bowel preparation (OR 0.89; 95% CI, 0.65-1.21; P = 0.45; I2 = 0%; P = 0.52). The polyp detection rate (OR 0.94; 95% CI, 0.77-1.14; P = 0.52; I2 = 23%; P = 0.27) and adenoma detection rate (OR 0.87; 95% CI, 0.71-1.08; P = 0.21; I2 = 0%; P = 0.52) were similar between the groups. There were significantly higher odds of tolerability in patients consuming 1-day LRD compared with 3-day LRD (OR 1.64; 95% CI, 1.13-2.39; P < 0.01; I2 = 47%; P = 0.15). In addition, constipation was identified as the independent predictor of inadequate preparation (OR 1.98; 95% CI, 1.27-3.11; P < 0.01; I2 = 0%; P = 0.46). CONCLUSION: The present study demonstrated that a 1-day LRD was as effective as a 3-day CLD in the quality of bowel preparation before colonoscopy and significantly improved tolerability of patients. In addition, constipation is an independent risk factor of poor bowel preparation, and the duration of LRD in patients with constipation still needs further clinical trials.

One-Day versus Three-Day Low-Residue Diet and Bowel Preparation Quality before Colonoscopy: A Multicenter, Randomized, Controlled Trial.

BACKGROUND: One-day low-residue diet (LRD) is recommended before colonoscopy, but only three single-center trials compared the 1-day versus 3-day LRD. The aim of this multicenter study was to compare the impact of a 3-day versus 1-day LRD on its ability to adequately and successfully prepare the bowel of outpatients that require a colonoscopy. The outpatients' tolerance and adherence to the LRD were also considered. METHODS: Consecutive outpatients were randomized to 1-day versus 3-day LRD at three open-access endoscopy units. The primary endpoint consisted of the proportion of patients with a satisfactory degree of bowel cleanliness (Score 2-3 on the Boston Bowel Preparation Scale [BBPS] in each segment). Secondary endpoints were patients' tolerance and adherence to the prescribed diet evaluated by a standardized questionnaire. RESULTS: 289 patients were included in the study (1-day LRD arm = 143, 3-day LRD arm = 146). BBPS ≥2 was not significantly different in the two dietary regimens in any of the three colonic segments (71% vs. 72%, p = 0.9). The percentage of patients with incomplete preparation was similar in the two arms (9% vs. 9%; p = 1.0). No significant differences were found among colonoscopy findings in terms of abnormalities (81% vs. 84%, p = 0.8). Both groups scored similarly in overall tolerance to LRD (48% vs. 49%, p = 1.0) and also in whether they would have adopted a different dietary regimen (p = 0.3). CONCLUSION: Our multicenter randomized study confirmed that optimal bowel cleansing is reached through a 1-day LRD.

Efficacy and tolerability of a low-residue diet for bowel preparation: systematic review and meta-analysis.

BACKGROUND: Colorectal cancer (CRC) contributes significantly to cancer mortality worldwide. In an effort to reduce the risk of death, detection of polyps through colonoscopy is crucial. The success of the colonoscopy depends on the diet administered the day before the test. Our aim was to evaluate the efficacy, tolerability, and adverse effects of bowel preparation when using a low-residual diet (LRD) compared to a clear-liquid diet (CLD) the day before a scheduled colonoscopy. METHODS: PubMed/Medline, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL) and Scopus databases were searched. We included studies of patients undergoing a scheduled colonoscopy for CRC screening and surveillance or for diagnostic purposes that compared a LRD with a CLD the day before the colonoscopy. Efficacy, the primary outcome, was evaluated as the rate of adequate bowel preparation. Secondary outcomes were tolerability and adverse effects of bowel preparation. RESULTS: Thirteen RCTs (N = 2587) were included. Patients receiving a LRD compared to a CLD showed no difference in adequate bowel preparations (RR 1.02; 95% CI 0.99-1.05; I2 = 60%). However, the LRD improved patient tolerability (RR 1.17; 95% CI 1.12-1.23; I2 = 66%) and had fewer adverse effects (RR 0.89; 95% CI 0.84-0.94; I2 = 73%) compared to the CLD. Groups using a LRD with 4L of polyethylene glycol in a single dose or a LRD with < 2000 kcal < 32 g of fibres/day had better tolerability. CONCLUSION: Based on these findings, our recommendation is strong in favour of a LRD for bowel preparation of patients undergoing a scheduled colonoscopy. This diet could also be useful as a preoperative colonic preparation, but this requires further research.

Single-Day Low-Residue Diet Prior to Colonoscopy Demonstrates Improved Bowel Preparation Quality and Patient Tolerance over Clear Liquid Diet: A Randomized, Single-Blinded, Dual-Center Trial.

BACKGROUND AND AIMS: Patients often refer to bowel preparation and associated dietary restrictions as the greatest deterrents to having a colonoscopy completed or performed. Large studies comparing a low-residue diet (LRD) and a clear liquid diet (CLD) are still limited. The aim of this study is to compare LRD and CLD with regard to bowel preparation quality, tolerance, and satisfaction among a diverse patient population. METHODS: This study is a dual-center, randomized, single-blinded, prospective trial involving adult patients undergoing outpatient colonoscopy at the University of California Irvine Medical Center and an affiliated Veterans Administration hospital. Patients were randomized to consume either a CLD or a planned LRD for the full day prior to colonoscopy. Both groups consumed 4L split-dosed PEG-ELS. The adequacy of bowel preparation was evaluated using the Boston Bowel Preparation Score (BBPS). Adequate preparation was defined as a BBPS ≥ 6 with no individual segment less than a score of 2. Hunger and fatigue pre - and post-procedure were graded on a ten-point scale. Nausea, vomiting, bloating, abdominal cramping, overall discomfort, satisfaction with the diet, willingness to repeat the same preparation and overall experience were assessed. RESULTS: A total of 195 subjects who underwent colonoscopy from October 2014 to October 2017 were included. The mean BBPS for the LRD and CLD groups was 8.38 and 7.93, respectively (p = 0.1). There was a significantly higher number of adequate preparations in the LRD group compared to CLD (p = 0.05). Evening hunger scores just before starting the bowel preparation were significantly lower in the LRD than the CLD group, 2.81 versus 5.97, respectively (p = 0.006). Subjects in the LRD group showed significantly less nausea (p = 0.047) and bloating (p = 0.04). Symptom scores for vomiting, abdominal cramping, and overall discomfort were similar between the groups. Satisfaction with diet was significantly higher in the LRD group than CLD, 72% versus 37.66%, respectively (p < 0.001). The overall colonoscopy experience and the satisfaction with the preparation itself were also better reported in the LRD group (p < 0.001 and p = 0.002, respectively). CONCLUSIONS: This study, which included a diverse group of patients, demonstrated that patients using a LRD before colonoscopy achieve a bowel preparation quality that is superior to patients on a CLD restriction. This study shows that a low-residue diet improves patient satisfaction and results in significantly better tolerability of bowel preparation. As a less restrictive dietary regimen, the low-residue diet may help improve patient participation in colorectal cancer screening programs.

Oral antibiotics and a low-residue diet reduce the incidence of anastomotic leakage after left-sided colorectal surgery: a retrospective cohort study.

PURPOSE: Anastomotic leakage is a potential complication after colorectal surgery. We investigated the effects of oral antibiotics and a low-residue diet on the incidence of anastomotic leakage after left-sided colorectal surgery. METHODS: Outcomes were retrospectively compared between 64 patients who underwent mechanical bowel preparation alone (group A) and 183 patients who underwent mechanical bowel preparation with addition of oral kanamycin and metronidazole (group B) on the day before left-sided colorectal surgery. After surgery, patients in group A received a normal diet containing dietary fiber and those in group B received a low-residue diet. The primary outcome was the incidence of anastomotic leakage. Secondary outcomes were rates of other postoperative complications, length of postoperative hospital stay, and laboratory data. RESULTS: Anastomotic leakage, surgical site infection, and diarrhea were less common in group B than in group A (4.9% vs 18.8%, 6.6% vs 23.4%, and 25.7% vs 43.8%, respectively). Postoperative C-reactive protein levels were significantly lower in group B. The median postoperative hospital stay was significantly shorter in group B than in group A (8 days vs 9 days, P = 0.010). Adaptive double least absolute shrinkage and selection operator regression revealed that use of preoperative oral antibiotics and a postoperative low-residue diet were associated with lower incidence of anastomotic leakage (odds ratio 0.163, 95% confidence interval 0.062-0.430; P < 0.001). CONCLUSION: Oral antibiotics and a low-residue diet reduced the incidence of anastomotic leakage and shortened the postoperative hospital stay by 1 day.

A Short-Term Low-Fiber Diet Reduces Body Mass in Healthy Young Men: Implications for Weight-Sensitive Sports.

Athletes from weight-sensitive sports are reported to consume low-fiber diets (LOW) to induce acute reductions in body mass (BM). However, evidence supporting their efficacy is anecdotal. Therefore, we aimed to determine the effect of a LOW on acute changes in BM. Nineteen healthy males (32 ± 10 years, 1.79 ± 0.07 m, 77.5 ± 8.1 kg) consumed their habitual diet (∼30 g fiber/day) for 7 consecutive days followed by 4 days of a LOW (<10 g fiber/day) that was matched for energy and macronutrient content. Participants also matched their daily exercise load during LOW to that completed during habitual diet (p = .669, average 257 ± 141 arbitrary units). BM was significantly reduced in LOW versus habitual diet after 4 days (Δ = 0.40 ± 0.77 kg or 0.49% ± 0.91%, p < .05, effect size [ES] [95% confidence interval] = -0.53 [-1.17, 0.12]) and on the morning of Day 5 (Δ = 0.58 ± 0.83 kg or 0.74% ± 0.99%, p < .01, ES = -0.69 [-1.34, -0.03]). LOW resulted in moderately higher hunger (Δ = 5 ± 9 mm, p = .015, ES = 0.55 [-0.09, 1.20]), a decline in stool frequency from 2 ± 0 to 1 ± 0 bowel movements per day (p = .012, ES = 0.64 [-0.02, 1.29]) and stool softness decrease (p = .005). Nonetheless, participants reported the diet to be tolerable (n = 18/19) and were willing to repeat it (n = 16/19). Data demonstrate for the first time that consumption of a short-term LOW induces reductions in BM.

Increasing the low residue diet to 3 days does not improve the bowel cleansing in hard to prepare patients: Post hoc analysis of a randomized controlled trial.

BACKGROUND: Recent evidence suggests that the number of low residue diet (LRD) days does not influence the bowel cleansing quality in non-selected patients. However, there are not data in the subgroup of patients with risk factors of inadequate bowel cleansing. OBJECTIVE: The aim of this study was to assess whether a 3-day LRD improved the bowel cleansing quality in patients with risk factors of poor bowel cleansing. PATIENTS AND METHODS: Post hoc analysis of a randomized controlled trial carried out between December 2017 and March 2018 in a tertiary care hospital. Patients with high risk of poor bowel cleansing were selected following a validated score. The patients were randomized to the 1-day LRD or 3-day LRD groups. All patients received a 2-L split-dose of polyethylene glycol plus ascorbic acid. Intention-to-treat (ITT) and per-protocol (PP) analyses were conducted for the main outcome. RESULTS: 135 patients (1-day LRD group=67, 3-day LRD=68) were included. The rate of adequate cleansing quality was not significantly different between the groups in the ITT analysis: 76.1%, 95% CI: [64.6-84.8] vs. 79.4%, 95% CI: [68.2-87.4]; odds ratio (OR) 1.2, 95% CI [0.54-2.73]) or in the PP analysis: 77.3%, 95% CI: [65.7-85.8] vs. 80.3%, 95% CI: [69.0-88.3]; OR 1.2, 95% CI [0.52-2.77]). Compliance with the diet or cleansing solution, satisfaction or difficulties with the LRD and the polyp/adenoma detection rates were not significantly different. CONCLUSION: Our results suggest that 1-day LRD is not inferior to 3-day LRD in patients with risk factors of inadequate bowel cleansing.

Favorable outcomes of prepackaged low-residue diet on bowel preparation for colonoscopy: Endoscopist-blinded randomized controlled trial.

BACKGROUND AND AIM: 2 L polyethylene glycol plus an ascorbic acid (PEGA) is known to be as effective. However, 2 L polyethylene glycol-based regimens are often still difficult for patients to tolerate. Therefore, we conducted this study to evaluate the potential of 1 L PEGA with prepackaged low-residue diet (PLD) as an alternative to 2 L PEGA before colonoscopy. METHODS: The subjects were randomly assigned to either of the two groups. The 2 L PEGA group received 2 L PEGA split regimen. The 1 L PEGA with PLD group received PLD on the day preceding colonoscopy and 1 L PEGA. All endoscopic procedures were performed by one physician who did not know patients allocation. Bowel preparation status were graded using Boston Bowel Preparation Score (BBPS). A questionnaire regarding tolerability and safety was administered. This trial is registered at ClinicalTrials.gov (NCT03329339). RESULTS: A total of 173 patients completed the study (86 in the 2 L PEGA group and 87 in the 1 L PEGA with PLD group). Bowel preparation was adequate in 88.4% (76/86) of patients in the 2 L PEGA group and 93.1% of patients in the 1 L PEGA with PLD group (81/87, P = 0.28). The patients in the 1 L PEGA with PLD group had higher whole Boston Bowel Preparation Scale score (P = 0.02) and expressed more satisfaction and willingness to repeat the procedure (P < 0.01). There was no significant difference with respect to compliance or safety. CONCLUSION: 1 L PEGA with PLD showed equivalent efficacy, greater satisfaction, and more willingness to repeat compared with 2 L PEGA for bowel preparation.

A randomized controlled trial comparing a prepackaged low-residue diet with a restricted diet for colonoscopy preparation: the impact on the results of colonoscopy in adenoma detection.

AIM: This study aimed to investigate the clinical utility of a prepackaged low-residue diet (PLD) compared with a restricted diet (RD) for colonoscopic bowel preparation. METHOD: A prospective randomized controlled trial was carried out with patients undergoing colonoscopy. One hundred patients were randomly assigned to PLD and RD groups. In the RD group, the patients received an information sheet containing acceptable low-residue options and instructions from the medical staff. All patients received 10 ml sodium picosulphate the day before colonoscopy and 1 l of polyethylene glycol with ascorbic acid (PEG-A) on the day of the colonoscopy. If the bowel preparation was not adequate, an additional PEG-A solution was given. The primary outcome was the efficacy of colonic cleansing as rated by the Boston Bowel Preparation Scale (BBPS). The additional amount of PEG-A solution, adenoma detection rate and patient tolerance were assessed as secondary outcomes. RESULTS: The BBPS score in the PLD group was 7.3 ± 1.7 compared with 6.5 ± 1.7 in the RD group. The quality of bowel preparation was significantly better in the PLD group (P < 0.05). The mean amount of additional PEG-A solution in the PLD group was smaller than in the RD group (293.8 ± 474.8 vs 444.1 ± 625.0 ml), but there was no statistical difference between the two groups. Adenoma detection rates and patient tolerance were similar in the two groups. CONCLUSION: Prepackaged low-residue diets PLD is superior to RD for bowel preparation for colonoscopy.

Bowel preparation protocol for hospitalized patients ages 50 years or older: A randomized controlled trial.

BACKGROUND: The incidence and mortality rate of colorectal cancer progressively increase with age and become particularly prominent after the age of 50 years. Therefore, the population that is ≥ 50 years in age requires long-term and regular colonoscopies. Uncomfortable bowel preparation is the main reason preventing patients from undergoing regular colonoscopies. The standard bowel preparation regimen of 4-L polyethylene glycol (PEG) is effective but poorly tolerated. AIM: To investigate an effective and comfortable bowel preparation regimen for hospitalized patients ≥ 50 years in age. METHODS: Patients were randomly assigned to group 1 (2-L PEG + 30-mL lactulose + a low-residue diet) or group 2 (4-L PEG). Adequate bowel preparation was defined as a Boston bowel preparation scale (BBPS) score of ≥ 6, with a score of ≥ 2 for each segment. Non-inferiority was prespecified with a margin of 10%. Additionally, the degree of comfort was assessed based on the comfort questionnaire. RESULTS: The proportion of patients with a BBPS score of ≥ 6 in group 1 was not significantly different from that in group 2, as demonstrated by intention-to-treat (91.2% vs 91.0%, P = 0.953) and per-protocol (91.8% vs 91.0%, P = 0.802) analyses. Furthermore, in patients ≥ 75 years in age, the proportion of BBPS scores of ≥ 6 in group 1 was not significantly different from that in group 2 (90.9% vs 97.0%, P = 0.716). Group 1 had higher comfort scores (8.85 ± 1.162 vs 7.59 ± 1.735, P < 0.001), longer sleep duration (6.86 ± 1.204 h vs 5.80 ± 1.730 h, P < 0.001), and fewer awakenings (1.42 ± 1.183 vs 2.04 ± 1.835, P = 0.026) than group 2. CONCLUSION: For hospitalized patients ≥ 50 years in age, the bowel preparation regimen comprising 2-L PEG + 30-mL lactulose + a low-residue diet produced a cleanse that was as effective as the 4-L PEG regimen and even provided better comfort.

The efficacy of preoperative low-residue diet on postoperative ileus following cesarean section.

OBJECTIVE: To evaluate the efficacy of preoperative low-residue diet on postoperative ileus in women undergoing elective cesarean section (CS). METHODS: This is a surgeon-blind, randomized controlled trial enrolling pregnant women at ≥39 weeks of gestation undergoing elective CS. Patients were preoperatively randomized to receive either low-residue diet (arm A) or free diet (arm B) starting from three days before surgery. The primary outcome was the postoperative ileus. The secondary outcomes were the postoperative pain (assessed through VAS scale), the quality of the surgical field (scored using a 5-point scale, from poor to excellent), postoperative complications, and the length of hospital stay. Perioperative data were collected and compared between groups. RESULTS: A total of 166 patients were enrolled and randomized in arm A (n = 83) and arm B (n = 83). Postoperative ileus over 24 h was significantly shorter in arm A, compared to arm B (19.3% vs 36.2%). The surgical evaluation of small intestine was scored ≥3 in 96.4% of arm A patients versus 80.7% in arm B, while evaluation of large intestine, respectively, in 97.7% and 81.9%. Postoperative pain after 12 h from CS was significantly lower in arm A (VAS, 3.4 ± 1.7) compared to arm B (VAS, 4.1 ± 1.8). There were no significant differences as regards postoperative pain at 24 and 48 h, nausea/vomit, surgical complications, and hospital stay. CONCLUSIONS: Implementation of a preoperative low-residue diet for women scheduled for elective CS would reduce postoperative ileus and pain. Further large-scale studies are required before translating these research findings into routine obstetrical practice.

Prepackaged formula low-residue diet vs. self-prepared low-residue diet before colonoscopy: A multicenter randomized controlled trial.

Background and aims: Compared with self-prepared LRD, a prepackaged low-residue diet (LRD) can improve patient compliance, but whether it can further improve the quality of bowel preparation is uncertain. The study aimed to compare the application of the prepackaged formula LRD with self-prepared LRD in bowel preparation for colonoscopy. Methods: A multicenter randomized controlled trial was conducted in 15 centers. The eligible subjects were randomly assigned to one of two groups: the formula LRD group and the self-prepared LRD group. On the day before the colonoscopy, subjects in the self-prepared LRD group were instructed to consume a restricted LRD prepared by themselves, while subjects in the formula LRD group were given six bags of prepackaged formula LRD and instructed to consume them according to their individual need. The primary outcome was an adequate bowel preparation rate. Secondary outcomes mainly included Boston Bowel Preparation Scale (BBPS) scores, dietary restriction compliance rate, tolerance, satisfaction, adenoma detection rate (ADR), and adverse reactions. The trial was registered at ClinicalTrials.gov under the identifier NCT03943758. Results: A total of 550 subjects were recruited. Compared with the self-prepared LRD group, the formula LRD group showed a higher adequate bowel preparation rate (94.5 vs. 80.4%; P < 0.01), BBPS scores (7.87 ± 1.13 vs. 6.75 ± 1.47; P < 0.01), dietary compliance rate (92.4 vs. 78.9%; P < 0.01), tolerance (P < 0.01 in degree of hunger, intensity of physical strength, and negative influence on daily activities), satisfaction (8.56 ± 1.61 vs. 7.20 ± 2.02; P < 0.01), and ADR (25.6 vs. 16.0%; P < 0.01). There was no significant difference in adverse reactions. Conclusion: Compared with self-prepared LRD, the formula LRD showed similar safety and higher bowel preparation quality, compliance, and tolerance in bowel preparation. More formula LRDs could be designed according to different dietary habits and ethnic populations, and further researches are warranted to confirm their effect. Clinical trial registration: https://register.clinicaltrials.gov, identifier: NCT03943758.

Preoperative low-residue diet in gynecological surgery.

OBJECTIVE: To evaluate the impact of preoperative low-residue diet on intra- and postoperative outcomes among gynecological surgical patients. METHODS: This is a surgeon-blind, randomized controlled trial enrolling patients undergoing elective surgery for either benign disease or endometrial carcinoma. Patients were preoperatively randomized to receive either low-residue diet (arm A) or free diet (arm B) starting from three days before surgery. The primary outcome was the quality of the surgical field (scored using a 5-point scale, from poor to excellent). Secondary outcomes were postoperative pain (assessed through VAS scale), postoperative complications, operative time, time to first passage of flatus, length of hospital stay. Perioperative data were collected and compared between groups. RESULTS: A total of 96 patients were enrolled and randomized in arm A (n = 49; 51%) and arm B (n = 47; 49%). The mean age was 47.8 ± 15.6 years in arm A and 48.1 ± 11.3 years in arm B. Endometrial cancer patients were 16.3% in arm A and 10.6% in arm B, and patients with benign disease were 83.7% and 89.4%, respectively. The surgical evaluation of the small intestine was scored < 3 in 2.0% of arm A patients versus 31.9% in arm B (Odds Ratio (OR), 0.04 [95% CI, 0.01-0.35]; p < 0.001), and in 6.1% and 44.7% (OR, 0.08 [95% CI, 0.02-0.30]; p < 0.001), respectively, for large intestine. The mean operative time was 90.4 ± 33.4 min in arm A versus 111.6 ± 37.5 in arm B (Mean Difference (MD): -21.20 [95% CI, -35.43, -6.97]; p = 0.003). The number of patients who reported the time to first flatus within 24 h after surgery was significantly higher in arm A compared with arm B (77.6% vs 44.7%; OR, 4.28 [95% CI, 1.77-10.35]; p = 0.002). No significant differences in terms of postoperative complications, pain, and length of hospital stay were observed between the two groups. CONCLUSION: Introducing a preoperative low-residue diet could improve the quality of the surgical field and reduce both the operative duration and the time to first passage of flatus among patients undergoing gynecological surgery. Further large-scale studies are required to confirm these findings.

Comparison of the effect of 1-day and 2-day low residue diets on the quality of bowel preparation before colonoscopy.

BACKGROUND/AIM: Low residue diet (LRD) has a similar quality of bowel preparation with clear liquid diet before colonoscopy, but improved patient tolerance. However, the optimal LRD duration is still controversial. In this study, we have compared the effect of a 1-day LRD and 2-day LRD on the quality of bowel preparation and patient tolerance. PATIENTS AND METHODS: Our prospective, randomized, single-blind trial, single-blind, trial compared two dietary regimens administered the day before colonoscopy. All patients were administered PEG-ES and simethicone for bowel preparation. The primary outcome measure was bowel preparation quality. The secondary outcome measures were insertion time, withdrawal time, polyp detection rate, patient tolerance, and willingness to use the same diet for bowel preparation again. Bowel preparation quality was evaluated using the Boston bowel preparation scale (BBPS). Patient tolerance was evaluated using a hunger-comfort scale. RESULTS: There was no significant difference in bowel preparation quality between the 2 groups. The 1-day LRD group had a BBPS score of 6.48 ± 1.59 points, while the 2-day LRD group had a score of 6.42 ± 1.06 points (P > 0.05). The groups reported similar colonoscope insertion times, withdrawal times, polyp detection rates and patient tolerance scores (hunger-comfort scores). The numbers of patients who reported that compliance as easy or very easy were 126 (78.2%) in the 1-day group versus 88 (55.0%) in the 2 day group (P < 0.05) and the numbers who were willing to use the diet again in the future were 154 (95.7%) in the 1-day group versus 131 (81.9%) in the 2 day group (P < 0.05). CONCLUSION: LRD duration (1 day or 2 days) had no significant effect on bowel preparation quality. Patients in the 1-day LRD group had higher tolerance and satisfaction levels than patients in the 2-day LRD group. However, overall satisfaction was higher with the 1-day LRD group than with the 2-day LRD group.

Low-residue diet fed to rabbits induces histomorphological and biomechanical remodeling of small intestine.

BACKGROUND: The composition of ingested food is important for the gut microbiome and intestinal homeostasis. We have previously demonstrated that the structure and mechanical properties in the small intestine remodel significantly during fasting. However, it is not clear to what extent the intestinal mechanical properties changes when the composition of food is changed. This study aimed to investigate the passive biomechanical properties and intestinal tissue remodeling in rabbits fed a low-residue diet. METHODS: New Zealand rabbits (control group n=6, intervention group n=7) were studied. Segments from duodenum, jejunum and ileum were excised. The intestinal diameter and length were obtained from digitized images of the segments at preselected luminal pressure levels and at no-load and zero-stress states. Circumferential and longitudinal stresses (force per area) and strains (deformation) were computed from the length, diameter and pressure data referenced to the zero-stress state geometry. Histomorphometric data were also obtained. KEY RESULTS: The wet weight-per-unit length, wall thickness and wall area decreased in the intervention group (P<.05, P<.01). Histological measurement confirmed that the wall thickness decreased in all three segments, which was primarily due to mucosal thinning (P<.05). The opening angle tended to increase in all segments in the intervention group. Significant difference between the two groups was found for the jejunum (P<.05). Feeding the low-residue diet shifted the circumferential stress-strain curves in the intervention group to the right, indicating intestinal wall softening. CONCLUSIONS & INFERENCES: Low-residue diet in rabbits for 1 month induces location-dependent histomorphometric and biomechanical remodeling of the intestine.

Increasing the low residue diet to 3 days does not improve the bowel cleansing in hard to prepare patients: Post hoc analysis of a randomized controlled trial / Aumentar la dieta baja en residuos a 3 días no mejora la limpieza intestinal en pacientes difíciles de preparar: análisis post-hoc de un ensayo controlado aleatorizado

Background: Recent evidence suggests that the number of low residue diet (LRD) days does not influence the bowel cleansing quality in non-selected patients. However, there are not data in the subgroup of patients with risk factors of inadequate bowel cleansing. Objective: The aim of this study was to assess whether a 3-day LRD improved the bowel cleansing quality in patients with risk factors of poor bowel cleansing. Patients and methods: Post hoc analysis of a randomized controlled trial carried out between December 2017 and March 2018 in a tertiary care hospital. Patients with high risk of poor bowel cleansing were selected following a validated score. The patients were randomized to the 1-day LRD or 3-day LRD groups. All patients received a 2-L split-dose of polyethylene glycol plus ascorbic acid. Intention-to-treat (ITT) and per-protocol (PP) analyses were conducted for the main outcome. Results: 135 patients (1-day LRD group=67, 3-day LRD=68) were included. The rate of adequate cleansing quality was not significantly different between the groups in the ITT analysis: 76.1%, 95% CI: [64.6–84.8] vs. 79.4%, 95% CI: [68.2–87.4]; odds ratio (OR) 1.2, 95% CI [0.54–2.73]) or in the PP analysis: 77.3%, 95% CI: [65.7–85.8] vs. 80.3%, 95% CI: [69.0–88.3]; OR 1.2, 95% CI [0.52–2.77]). Compliance with the diet or cleansing solution, satisfaction or difficulties with the LRD and the polyp/adenoma detection rates were not significantly different. Conclusion: Our results suggest that 1-day LRD is not inferior to 3-day LRD in patients with risk factors of inadequate bowel cleansing.(AU)

Antecedentes: La evidencia reciente sugiere que el número de días de dieta baja en residuos (DBR) no influye en la calidad de la limpieza intestinal en pacientes no seleccionados. Sin embargo, no hay datos en el subgrupo de pacientes con factores de riesgo de una limpieza intestinal insuficiente. Objetivo: El objetivo de este estudio fue evaluar si una DBR de 3 días mejoraba o no la calidad de la limpieza intestinal en pacientes con factores de riesgo de limpieza intestinal deficiente. Pacientes y métodos: Análisis post-hoc de un ensayo controlado aleatorizado realizado entre diciembre de 2017 y marzo de 2018 en un hospital de atención terciaria. Los pacientes con alto riesgo de limpieza intestinal deficiente se seleccionaron mediante una puntuación validada. Los pacientes se aleatorizaron a los grupos de DBR de un día o DBR de 3 días. Todos los pacientes recibieron una dosis dividida de 2l de polietilenglicol más ácido ascórbico. Se realizaron análisis por intención de tratar (IdT) y por protocolo (PP) para el criterio principal de valoración. Resultados: Se incluyeron 135 pacientes (grupo DBR de un día=67, DBR de 3 días=68). No se observaron diferencias significativas en la tasa de calidad de limpieza suficiente entre los grupos en el análisis por IdT (76,1%; IC del 95%: [64,6-84,8] frente al 79,4 7%, IC del 95%: [68,2-87,4]; razón de posibilidades (OR): 1,2; IC del 95%: [0,54-2,73]) o en el análisis PP: (77,3%; IC del 95 %: [65,7-85,8] frente al 80,3%, IC del 95%: [69,0-88,3]; OR: 1,2; IC del 95% [0,52 -2,77]). No se observaron diferencias significativas en el cumplimiento de la dieta o con la solución limpiadora, en la satisfacción o las dificultades con la DBR y en las tasas de detección de pólipos/adenomas. Conclusión: Nuestros resultados sugieren que la DBR de un día no es inferior a la DBR de 3 días en pacientes con factores de riesgo de limpieza intestinal insuficiente.(AU)

Low-residue and low-fiber diets in gastrointestinal disease management.

Recently, low-residue diets were removed from the American Academy of Nutrition and Dietetics' Nutrition Care Manual due to the lack of a scientifically accepted quantitative definition and the unavailability of a method to estimate the amount of food residue produced. This narrative review focuses on defining the similarities and/or discrepancies between low-residue and low-fiber diets and on the diagnostic and therapeutic values of these diets in gastrointestinal disease management. Diagnostically, a low-fiber/low-residue diet is used in bowel preparation. A bowel preparation is a cleansing of the intestines of fecal matter and secretions conducted before a diagnostic procedure. Therapeutically, a low-fiber/low-residue diet is part of the treatment of acute relapses in different bowel diseases. The available evidence on low-residue and low-fiber diets is summarized. The main findings showed that within human disease research, the terms "low residue" and "low fiber" are used interchangeably, and information related to the quantity of residue in the diet usually refers to the amount of fiber. Low-fiber/low-residue diets are further explored in both diagnostic and therapeutic situations. On the basis of this literature review, the authors suggest redefining a low-residue diet as a low-fiber diet and to quantitatively define a low-fiber diet as a diet with a maximum of 10 g fiber/d. A low-fiber diet instead of a low-residue diet is recommended as a diagnostic value or as specific therapy for gastrointestinal conditions.