Outcomes of ERCP in Patients With Cystic Fibrosis: A Nationwide Inpatient Assessment.

BACKGROUND: Cystic fibrosis (CF) is a multisystem disorder that leads to abnormal transport of chloride and sodium across secretory epithelia resulting in thickened, viscous secretions in the bronchi, biliary tract, pancreas, intestine, and the reproductive system. Defects in the biliary tract can predispose to stone formation requiring endoscopic retrograde cholangiopancreatography (ERCP). However, there is a paucity of data assessing ERCP outcomes in patients with CF. METHODS: We identified patients from the Healthcare Cost and Utilization Project (HCUP)-National Inpatient Sample (NIS) between the years 2016 and 2020. Our study group included patients with CF of all ages who underwent an inpatient ERCP. We used ICD10 diagnostic and procedural codes to identify patients, procedures, and complications of the procedure. RESULTS: From 2016 to 2020, a total of 860,679 inpatient ERCPs were identified. Of these procedures, 535 (0.06%) were performed in patients with CF. The mean age of patients with CF undergoing ERCP was 60.62 years, of which 48% were males and 52% were females. Patients in the CF group had a higher incidence of post-ERCP pneumothorax (0.93%) than the patients in the non-CF group (0.15%). The occurrence of other ERCP-related adverse events was similar in both groups (P>0.05). On multivariate regression analysis, patients with CF were 1.75 times more likely to develop post-ERCP infections [odds ratio (OR): 1.75; 95% CI: 1.03-2.94; P=0.035) and 7.64 times more likely to develop post-ERCP pneumothorax (OR: 7.64; 95% CI: 1.03-56.5; P=0.046) compared to patients without CF after adjusting for confounders. The groups had no significant difference in mortality, post-ERCP pancreatitis, bleeding, perforation, pneumoperitoneum, and gas embolism. There was also no significant difference in the length of stay between the study and control groups. CONCLUSIONS: ERCP is a safe procedure in patients with CF with a comparable risk of postprocedural complications and mortality to those who do not have cystic fibrosis. However, patients with CF may experience a higher risk of post-ERCP infections and post-ERCP pneumothorax. Further studies are needed to prospectively evaluate outcomes of ERCP in patients with CF and to determine methods of mitigating adverse events.

Current Approaches for Monitoring of Patients with Inflammatory Bowel Diseases: A Narrative Review.

BACKGROUND: Patients with inflammatory bowel diseases (IBD) require proactive monitoring both during the active phase to evaluate therapeutic response and during the remission phase to evaluate relapse or colorectal cancer surveillance. However, monitoring may vary between patients with ulcerative colitis (UC) and Crohn's disease (CD), with distinct tools and intervals. METHODS: This narrative review aims to focus on modern approaches to IBD monitoring, considering international guidelines and expert consensus. RESULTS: The most recent European diagnostic guidelines advocate a combination of clinical, laboratory, endoscopic, and radiological parameters to evaluate the disease course of patients with IBD. Unfortunately, the conventional symptom-based therapeutic approach does not improve long-term outcomes and there is no single ideal biomarker available. Endoscopy plays a key role in evaluating response to therapy as well as monitoring disease activity. Recently, bedside intestinal ultrasound (IUS) has gained increasing interest and diffusion as it appears to offer several advantages including the monitoring of therapeutic response. CONCLUSION: In light of growing clinical advances, we present a schematic evidence-based monitoring algorithm that can be easily applied in clinical practice which combines all major monitoring modalities, including noninvasive tools such as IUS and video-capsule endoscopy.

EUS-Guided Gallbladder Drainage Using a Lumen-Apposing Metal Stent for Acute Cholecystitis: Results of a Nationwide Study with Long-Term Follow-Up.

BACKGROUND: Although endoscopic ultrasound-guided gallbladder drainage (EUS-GBD) using lumen-apposing metal stents (LAMS) has become one of the treatments of choice for acute cholecystitis (AC) in fragile patients, scant data are available on real-life settings and long-term outcomes. METHODS: We performed a multicenter retrospective study including EUS-guided GBD using LAMS for AC in 19 Italian centers from June 2014 to July 2020. The primary outcomes were technical and clinical success, and the secondary outcomes were the rate of adverse events (AE) and long-term follow-up. RESULTS: In total, 116 patients (48.3% female) were included, with a mean age of 82.7 ± 11 years. LAMS were placed, transgastric in 44.8% of cases, transduodenal in 53.3% and transjejunal in 1.7%, in patients with altered anatomy. Technical success was achieved in 94% and clinical success in 87.1% of cases. The mean follow-up was 309 days. AEs occurred in 12/116 pts (10.3%); 8/12 were intraprocedural, while 1 was classified as early (<15 days) and 3 as delayed (>15 days). According to the ASGE lexicon, two (16.7%) were mild, three (25%) were moderate, and seven (58.3%) were severe. No fatal AEs occurred. In subgroup analysis of 40 patients with a follow-up longer than one year, no recurrence of AC was observed. CONCLUSIONS: EUS-GBD had high technical and clinical success rates, despite the non-negligible rate of AEs, thus representing an effective treatment option for fragile patients.

Fecal Microbiota Transplantation as Emerging Treatment in European Countries 2.0.

Clostridioides difficile infection (CDI) is one of the most common healthcare-associated infections and one of the leading causes of morbidity and mortality in hospitalized patients in the world. Although several antibiotics effectively treat CDI, some individuals may not respond to these drugs and may be cured by transplanting stool from healthy donors. FMT has demonstrated extraordinary cure rates for the cure of CDI recurrences.Moreover, FMT has also been investigated in other disorders associated with the alteration of gut microbiota, such as inflammatory bowel disease (IBD), where the alterations of the gut microbiota ecology have been theorized to play a causative role. Although FMT is currently not recommended to cure IBD patients in clinical practice, several studies have been recently carried out with the ultimate goal to search new therapeutic options to patients.This review summarizes data on the use of FMT for the treatment of both CDI and IBD, with a special attention to highlight studies conducted in European countries.

Efficacy of 1 L polyethylene glycol plus ascorbate versus 4 L polyethylene glycol in split-dose for colonoscopy cleansing in out and inpatient: A multicentre, randomized trial (OVER 2019).

BACKGROUND AND AIMS: Adequate bowel cleansing is essential for colonoscopy quality. A novel 1 L polyethylene glycol plus ascorbate (1 L PEG+ASC) solution has been recently introduced. Nevertheless, the efficacy of 1 L PEG+ASC as compared to that of high-volume bowel preparation in both inpatients and outpatients is still unclear. PATIENTS AND METHODS: This single-blinded, non-inferiority study randomized patients undergoing colonoscopy to receive split-dose 1 L PEG+ASC or 4 L PEG. The primary endpoint was the overall cleansing success. Secondary endpoints were excellent cleansing and high-quality cleansing of the right colon, as well as lesions detection rate, patient compliance, tolerability and safety. RESULTS: Overall, 478 patients were randomized to 1 L PEG+ASC (N = 236) or 4 L PEG (N = 242). The 1 L PEG+ASC showed higher cleansing success rate (91.8% vs 83.6%; P=0.01) and a high-quality cleansing of the right colon (52.3% and 38.5%; P=0.004) compared to 4 L PEG. Moreover, 1 L PEG+ASC achieved a higher cleansing success in out-patients (96.3%% vs 88.6%; P=0.018), and a similar success rate in the in-patients (84.7% vs 76.7%; P=0.18). Adenoma detection rate, tolerability and incidence of adverse events were comparable between preparations. CONCLUSIONS: The 1 L PEG+ASC showed higher efficacy in achieving adequate colon cleansing compared with 4 L PEG, particularly in the right colon. No differences in the tolerability and safety were detected.

Focal Active Colitis: What Are Its Clinical Implications? A Narrative Review.

Focal active colitis (FAC) is described as a histolopathological term indicating the isolated finding of focal neutrophil infiltration in the colonic crypts. Currently, there exist numerous debates regarding the clinical significance of diagnosing FAC, which may or may not have clinical relevance as it is frequently detected in colorectal biopsies without any other microscopic abnormalities. The objective of this narrative review is to provide an overview of the available evidence concerning the clinical implications of FAC, both in the adult population (among five studies available in the scientific literature) and in the pediatric context (based on two available studies).

Time to establish an international vaccine candidate pool for potential highly infectious respiratory disease: a community's view.

In counteracting highly infectious and disruptive respiratory diseases such as COVID-19, vaccination remains the primary and safest way to prevent disease, reduce the severity of illness, and save lives. Unfortunately, vaccination is often not the first intervention deployed for a new pandemic, as it takes time to develop and test vaccines, and confirmation of safety requires a period of observation after vaccination to detect potential late-onset vaccine-associated adverse events. In the meantime, nonpharmacologic public health interventions such as mask-wearing and social distancing can provide some degree of protection. As climate change, with its environmental impacts on pathogen evolution and international mobility continue to rise, highly infectious respiratory diseases will likely emerge more frequently and their impact is expected to be substantial. How quickly a safe and efficacious vaccine can be deployed against rising infectious respiratory diseases may be the most important challenge that humanity will face in the near future. While some organizations are engaged in addressing the World Health Organization's "blueprint for priority diseases", the lack of worldwide preparedness, and the uncertainty around universal vaccine availability, remain major concerns. We therefore propose the establishment of an international candidate vaccine pool repository for potential respiratory diseases, supported by multiple stakeholders and countries that contribute facilities, technologies, and other medical and financial resources. The types and categories of candidate vaccines can be determined based on information from previous pandemics and epidemics. Each participant country or region can focus on developing one or a few vaccine types or categories, together covering most if not all possible potential infectious diseases. The safety of these vaccines can be tested using animal models. Information for effective candidates that can be potentially applied to humans will then be shared across all participants. When a new pandemic arises, these pre-selected and tested vaccines can be quickly tested in RCTs for human populations.

Real-Time Computer-Aided Detection of Colorectal Neoplasia During Colonoscopy : A Systematic Review and Meta-analysis.

BACKGROUND: Artificial intelligence computer-aided detection (CADe) of colorectal neoplasia during colonoscopy may increase adenoma detection rates (ADRs) and reduce adenoma miss rates, but it may increase overdiagnosis and overtreatment of nonneoplastic polyps. PURPOSE: To quantify the benefits and harms of CADe in randomized trials. DESIGN: Systematic review and meta-analysis. (PROSPERO: CRD42022293181). DATA SOURCES: Medline, Embase, and Scopus databases through February 2023. STUDY SELECTION: Randomized trials comparing CADe-assisted with standard colonoscopy for polyp and cancer detection. DATA EXTRACTION: Adenoma detection rate (proportion of patients with ≥1 adenoma), number of adenomas detected per colonoscopy, advanced adenoma (≥10 mm with high-grade dysplasia and villous histology), number of serrated lesions per colonoscopy, and adenoma miss rate were extracted as benefit outcomes. Number of polypectomies for nonneoplastic lesions and withdrawal time were extracted as harm outcomes. For each outcome, studies were pooled using a random-effects model. Certainty of evidence was assessed using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) framework. DATA SYNTHESIS: Twenty-one randomized trials on 18 232 patients were included. The ADR was higher in the CADe group than in the standard colonoscopy group (44.0% vs. 35.9%; relative risk, 1.24 [95% CI, 1.16 to 1.33]; low-certainty evidence), corresponding to a 55% (risk ratio, 0.45 [CI, 0.35 to 0.58]) relative reduction in miss rate (moderate-certainty evidence). More nonneoplastic polyps were removed in the CADe than the standard group (0.52 vs. 0.34 per colonoscopy; mean difference [MD], 0.18 polypectomy [CI, 0.11 to 0.26 polypectomy]; low-certainty evidence). Mean inspection time increased only marginally with CADe (MD, 0.47 minute [CI, 0.23 to 0.72 minute]; moderate-certainty evidence). LIMITATIONS: This review focused on surrogates of patient-important outcomes. Most patients, however, may consider cancer incidence and cancer-related mortality important outcomes. The effect of CADe on such patient-important outcomes remains unclear. CONCLUSION: The use of CADe for polyp detection during colonoscopy results in increased detection of adenomas but not advanced adenomas and in higher rates of unnecessary removal of nonneoplastic polyps. PRIMARY FUNDING SOURCE: European Commission Horizon 2020 Marie Sklodowska-Curie Individual Fellowship.

EUS-guided gallbladder drainage using a lumen-apposing metal stent as rescue treatment for malignant distal biliary obstruction: a large multicenter experience.

BACKGROUND AND AIMS: EUS-guided gallbladder drainage (EUS-GBD) with lumen-apposing metal stents (LAMSs) has been reported as a rescue treatment with encouraging results for the relief of jaundice in patients with distal malignant biliary obstruction (DMBO) and after failure of both ERCP and EUS-guided choledochoduodenostomy. METHODS: This was a multicenter retrospective analysis of all cases of consecutive EUS-GBD with LAMSs used as a rescue treatment for patients with DMBO in 14 Italian centers from June 2015 to June 2020. Primary endpoints were technical and clinical success, whereas the secondary endpoint was the adverse event (AE) rate. RESULTS: Forty-eight patients (52.1% women) with a mean age of 74.3 ± 11.7 years were included in the study. Biliary stricture was related to pancreatic adenocarcinoma (85.4%), duodenal adenocarcinoma (2.1%), cholangiocarcinoma (4.2%), ampullary cancer (2.1%), colon cancer (4.2%), and metastatic breast cancer (2.1%). The mean diameter of the common bile duct was 13.3 ± 2.8 mm. LAMSs were placed transgastrically in 58.3% of cases and transduodenally in 41.7%. Technical success was 100%, whereas clinical success was 81.3%, with a mean total bilirubin reduction after 2 weeks of 66.5%. The mean procedure time was 26.4 minutes, and the mean hospital stay was 9.2 ± 8.2 days. AEs occurred in 5 patients (10.4%): 3 were classified as intraprocedural and 2 were classified as delayed because they occurred after >15 days. When the American Society for Gastrointestinal Endoscopy lexicon was used, 2 AEs were mild and 3 were moderate (2 buried LAMSs). The mean follow-up was 122 days. CONCLUSIONS: Our study shows that EUS-GBD with LAMSs used as a rescue treatment for patients affected by DMBO represents a valuable option in terms of technical and clinical success rates, with an acceptable AE rate. To the best of our knowledge, this is the largest study concerning the use of this procedure. (Clinical trial registration number: NCT03903523.).

Prevalence of Osteopathy in Chronic Pancreatitis: A Systematic Review and Meta-Analysis.

INTRODUCTION: Individuals with chronic pancreatitis (CP) are at increased risk for nutritional complications during their clinical course. We appraised the literature to provide updated estimates of the prevalence and predictors of osteoporosis, osteopenia, and osteopathy in CP using a systematic review and meta-analysis. METHODS: Search strategies were developed for major databases from inception through October 2021. Outcomes of interest included rates of osteopenia and osteoporosis based on dual-energy X-ray absorptiometry scans and risk factors. A random-effects model was used for analysis, and results were expressed as pooled cumulative rates along with 95% confidence interval (CI). RESULTS: From an initial total of 1,704 identified articles, we ultimately selected 17 studies that involved 1,659 subjects (n = 1,067 men) with CP. The pooled rate of osteopathy was 58% (95% CI: 49%-67%; P < 0.001; I 2 = 91.8%). The pooled rate of osteoporosis was 18% (95% CI: 12%-23%; P < 0.001; I 2 = 86.3%), and the pooled rate of osteopenia was 39% (95% CI: 31%-48%; P < 0.001; I 2 = 91.53%). In the systematic review, factors associated with decreased bone mineral density included smoking, alcohol consumption, older age, female sex, low body mass index, decreased vitamins D and K, and fecal elastase levels. DISCUSSION: Patients with CP have high rates of osteopathy when assessed with dual-energy X-ray absorptiometry imaging. Additional studies with longitudinal follow-up are needed to understand the observed heterogeneity, the cumulative burden of disease, and rate of bone loss in CP.

Performance and Safety of EUS Ablation Techniques for Pancreatic Cystic Lesions: A Systematic Review and Meta-Analysis.

BACKGROUND: Pancreatic cystic lesions (PCL) represent an increasingly diagnosed condition with significant burden to patients' lives and medical resources. Endoscopic ultrasound (EUS) ablation techniques have been utilized to treat focal pancreatic lesions. This systematic review with meta-analysis aims to assess the efficacy of EUS ablation on PCL in terms of complete or partial response and safety. METHODS: A systematic search in Medline, Cochrane and Scopus databases was performed in April 2023 for studies assessing the performance of the various EUS ablation techniques. The primary outcome was complete cyst resolution, defined as cyst disappearance in follow-up imaging. Secondary outcomes included partial resolution (reduction in PCL size), and adverse events rate. A subgroup analysis was planned to evaluate the impact of the available ablation techniques (ethanol, ethanol/paclitaxel, radiofrequency ablation (RFA), and lauromacrogol) on the results. Meta-analyses using a random effects model were conducted and the results were reported as percentages with 95% confidence intervals (95%CI). RESULTS: Fifteen studies (840 patients) were eligible for analysis. Complete cyst resolution after EUS ablation was achieved in 44% of cases (95%CI: 31-57; 352/767; I2 = 93.7%), and the respective partial response rate was 30% (95%CI: 20-39; 206/767; I2 = 86.1%). Adverse events were recorded in 14% (95%CI: 8-20; 164/840; I2 = 87.2%) of cases, rated as mild in 10% (95%CI: 5-15; 128/840; I2 = 86.7%), and severe in 4% (95%CI: 3-5; 36/840; I2 = 0%). The subgroup analysis for the primary outcome revealed rates of 70% (95%CI: 64-76; I2 = 42.3%) for ethanol/paclitaxel, 44% (95%CI: 33-54; I2= 0%) for lauromacrogol, 32% (95%CI: 27-36; I2 = 88.4%) for ethanol, and 13% (95%CI: 4-22; I2 = 95.8%) for RFA. Considering adverse events, the ethanol-based subgroup rated the highest percentage (16%; 95%CI: 13-20; I2 = 91.0%). CONCLUSION: EUS ablation of pancreatic cysts provides acceptable rates of complete resolution and a low incidence of severe adverse events, with chemoablative agents yielding higher performance rates.

Effectiveness and application of artificial intelligence for endoscopic screening of colorectal cancer: the future is now.

INTRODUCTION: Artificial intelligence (AI) in gastrointestinal endoscopy includes systems designed to interpret medical images and increase sensitivity during examination. This may be a promising solution to human biases and may provide support during diagnostic endoscopy. AREAS COVERED: This review aims to summarize and evaluate data supporting AI technologies in lower endoscopy, addressing their effectiveness, limitations, and future perspectives. EXPERT OPINION: Computer-aided detection (CADe) systems have been studied with promising results, allowing for an increase in adenoma detection rate (ADR), adenoma per colonoscopy (APC), and a reduction in adenoma miss rate (AMR). This may lead to an increase in the sensitivity of endoscopic examinations and a reduction in the risk of interval-colorectal cancer. In addition, computer-aided characterization (CADx) has also been implemented, aiming to distinguish adenomatous and non-adenomatous lesions through real-time assessment using advanced endoscopic imaging techniques. Moreover, computer-aided quality (CADq) systems have been developed with the aim of standardizing quality measures in colonoscopy (e.g. withdrawal time and adequacy of bowel cleansing) both to improve the quality of examinations and set a reference standard for randomized controlled trials.

Meta-analysis: Post-COVID-19 functional dyspepsia and irritable bowel syndrome.

INTRODUCTION: The burden of post-COVID-19 functional dyspepsia (FD) and irritable bowel syndrome (IBS) remains unclear. The aim of this meta-analysis was to estimate the rate of post-COVID-19 FD and IBS. METHODS: MEDLINE, Scopus and Embase were searched through 17 December 2022. Studies reporting the incidence of FD and/or IBS in COVID-19 survivors and controls (without COVID-19), when available, according to the Rome criteria, were included. Estimated incidence with 95% confidence intervals (CI) was pooled. The odds ratio (OR) with 95% confidence intervals (CI) was pooled; heterogeneity was expressed as I2 . RESULTS: Ten studies met the inclusion criteria and were included in the analysis. Overall, four studies including 1199 COVID-19 patients were considered for FD. Post-COVID-19 FD was reported by 72 patients (4%, 95% CI: 3%-5% and I2 0%). The pooled OR for FD development (three studies) in post-COVID-19 patients compared to controls was 8.07 (95% CI: 0.84-77.87, p = 0.071 and I2 = 67.9%). Overall, 10 studies including 2763 COVID-19 patients were considered for IBS. Post-COVID-19 IBS was reported by 195 patients (12%, 95% CI: 8%-16%, I2 95.6% and Egger's p = 0.002 test). The pooled OR for IBS development (four studies) in COVID-19 patients compared to controls was 6.27 (95% CI: 0.88-44.76, p = 0.067 and I2 = 81.4%); considering only studies with a prospective COVID-19 cohort (three studies), the pooled OR was 12.92 (95% CI: 3.58-46.60, p < 0.001 and I2 = 0%). CONCLUSIONS: COVID-19 survivors were found to be at risk for IBS development compared to controls. No definitive data are available for FD.

Safety of endoscopic pancreatic necrosectomy compared with percutaneous and surgical necrosectomy: a nationwide inpatient study.

Background and study aims Pancreatic necrosis is an independent predictor of morbidity and mortality among patients with acute pancreatitis. We compared the safety and outcomes of three techniques including endoscopic necrosectomy, fluoroscopy-guided percutaneous necrosectomy by an interventional radiologist, and surgical necrosectomy. Patients and methods Using the Nationwide Readmissions Database, we identified hospitalized patients who underwent pancreatic necrosectomy from 2016 to 2019. They were identified using the International Classification of Diseases, 10th Revision, Procedure Coding System. Results: Of the 2,281 patients meeting the selection criteria, the method of pancreatic necrosectomy was as follows: endoscopy (n = 672), percutaneous (n = 1,338), and surgery (n = 271). Compared to surgery, the rate of mortality was lowest for endoscopy (hazard ratio (HR) 0.27; 95 % CI 0.08-0.90; P  = 0.033) followed by percutaneous (HR 0.44; 95 % CI, 0.20-0.98; P  = 0.045). Endoscopy was associated with less post-procedure bleeding compared to percutaneous and surgical necrosectomy ( P  < 0.001), as well as lower rates of post-procedure renal failure ( P  < 0.001) and respiratory failure ( P  = 0.002). Endoscopy was associated with average shorter lengths of stay and total hospital costs when compared with percutaneous and surgical approaches, respectively (20.1 vs 25.8 vs 38.3 days; P  < 0.001) and ($ 57K vs $ 76K vs $ 123K; P  < 0.001). Conclusions Endoscopic necrosectomy is associated with significantly lower risk of inpatient mortality, adverse events, length of stay, and cost when compared to percutaneous and surgical approaches.

Fecal microbiota transplantation for recurrent Clostridioides difficile infection in patients with concurrent ulcerative colitis.

AIMS: Clostridioides difficile infection (CDI) is a major challenge for healthcare systems. Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease, is a risk factor for primary and recurrent CDI (rCDI). Moreover, CDI itself often worsens the clinical picture of IBD, increasing the risk of complications. Fecal microbiota transplantation (FMT) is a highly effective treatment for rCDI, but data from patients with IBD and CDI are limited and often referred to mixed cohorts. We aimed to report outcomes from a cohort of patients with UC treated with FMT for rCDI superinfection. METHODS AND RESULTS: In a retrospective, single-centre cohort study we evaluated characteristics and outcomes of patients with UC who received FMT for rCDI. The primary outcome was negative C. difficile toxin 8 weeks after FMT. Thirty-five patients were included in the analysis. Sixteen patients were cured after single FMT, while 19 patients received repeat FMT. Overall, FMT cured rCDI in 32 patients (91%), and repeat FMT was significantly associated with sustained cure of CDI compared with single FMT (84% vs 50%, p = 0.018). Twenty-four patients (69%) experienced remission or an amelioration of UC activity. Serious adverse events were not observed. CONCLUSIONS: In our cohort of patients with UC, FMT was highly effective in curing rCDI without severe adverse events and repeat FMT was significantly associated with CDI cure. Most patients also experienced remission or amelioration of UC activity after FMT. Our findings suggest that a sequential FMT protocol may be used routinely in patients with UC and rCDI.

Factors affecting the quality of bowel preparation for colonoscopy in hard-to-prepare patients: Evidence from the literature.

Adequate bowel cleansing is critical for a high-quality colonoscopy because it affects diagnostic accuracy and adenoma detection. Nevertheless, almost a quarter of procedures are still carried out with suboptimal preparation, resulting in longer procedure times, higher risk of complications, and higher likelihood of missing lesions. Current guidelines recommend high-volume or low-volume polyethylene glycol (PEG)/non-PEG-based split-dose regimens. In patients who have had insufficient bowel cleansing, the colonoscopy should be repeated the same day or the next day with additional bowel cleansing as a salvage option. A strategy that includes a prolonged low-fiber diet, a split preparation regimen, and a colonoscopy within 5 h of the end of preparation may increase cleansing success rates in the elderly. Furthermore, even though no specific product is specifically recommended in the other cases for difficult-to-prepare patients, clinical evidence suggests that 1-L PEG plus ascorbic acid preparation are associated with higher cleansing success in hospitalized and inflammatory bowel disease patients. Patients with severe renal insufficiency (creatinine clearance < 30 mL/min) should be prepared with isotonic high volume PEG solutions. Few data on cirrhotic patients are currently available, and no trials have been conducted in this population. An accurate characterization of procedural and patient variables may lead to a more personalized approach to bowel preparation, especially in patients undergoing resection of left colon lesions, where intestinal preparation has a poor outcome. The purpose of this review was to summarize the evidence on the risk factors influencing the quality of bowel cleansing in difficult-to-prepare patients, as well as strategies to improve colonoscopy preparation in these patients.