Clinical and endoscopic characteristics of sessile serrated lesions with dysplasia/carcinoma

Background/Aims@#Some sessile serrated lesions (SSLs) progress into dysplasia and colorectal cancer, however, the clinical and endoscopic characteristics of SSLs with dysplasia remain to be determined. In this study, we elucidated these characteristics in SSLs with dysplasia/carcinoma, compared with those of SSLs without dysplasia. @*Methods@#We retrospectively collected the clinical, endoscopic, and pathological data of 254 SSLs from 216 patients endoscopically resected between January 2009 and December 2020. @*Results@#All SSLs included 179 without dysplasia and 75 with dysplasia/carcinoma, including 55 with low-grade dysplasia, 10 with high-grade dysplasia, and 10 with submucosal cancer. In clinical characteristics, SSLs with dysplasia/carcinoma were significantly associated with advanced age, metabolic diseases, and high-risk adenomas. In endoscopic characteristics, SSLs with dysplasia/carcinoma were significantly associated with the distal colon, large size, polypoid morphology, surface-changes, no mucus cap, and narrow-band imaging international colorectal endoscopic classification (NICE) type 2/3. In the multivariate analysis, high-risk adenomas (odds ratio [OR], 2.98; p = 0.01), large size (OR, 1.18; p < 0.01), depression (OR, 11.74; p = 0.03), and NICE type 2/3 (OR, 14.97; p < 0.01) were significantly associated with SSLs with dysplasia/carcinoma. @*Conclusions@#SSLs had a higher risk of dysplasia in the distal colon than in the proximal colon. SSLs with large size, depression, and adenomatous surface-patterns, as well as those in patients with high-risk adenomas, increased the risk of dysplasia/ carcinoma. This suggests that the clinical and endoscopic characteristics can aid in the diagnosis and management of SSLs with dysplasia/carcinoma.

Deep learning predicts the differentiation of kidney organoids derived from human induced pluripotent stem cells

Kidney organoids derived from human pluripotent stem cells (hPSCs) contain multilineage nephrogenic progenitor cells and can recapitulate the development of the kidney. Kidney organoids derived from hPSCs have the potential to be applied in regenerative medicine as well as renal disease modeling, drug screening, and nephrotoxicity testing. Despite biotechnological advances, individual differences in morphological and growth characteristics among kidney organoids need to be addressed before clinical and commercial application. In this study, we hypothesized that an automated noninvasive method based on deep learning of bright-field images of kidney organoids can predict their differentiation status. Methods: Bright-field images of kidney organoids were collected on day 18 after differentiation. To train convolutional neural networks (CNNs), we utilized a transfer learning approach. CNNs were trained to predict the differentiation of kidney organoids on bright-field images based on the messenger RNA expression of renal tubular epithelial cells as well as podocytes. Results: The best prediction model was DenseNet121 with a total Pearson correlation coefficient score of 0.783 on a test dataset. W classified the kidney organoids into two categories: organoids with above-average gene expression (Positive) and those with below-average gene expression (Negative). Comparing the best-performing CNN with human-based classifiers, the CNN algorithm had a receiver operating characteristic-area under the curve (AUC) score of 0.85, while the experts had an AUC score of 0.48. Conclusion: These results confirmed our original hypothesis and demonstrated that our artificial intelligence algorithm can successfully recognize the differentiation status of kidney organoids.

A large and pedunculated inflammatory pseudotumor with pseudosarcomatous change of the cecum mimicking a malignant polyp: a case report and literature review

Inflammatory pseudotumor (IPT) is a rare benign tumor of unknown etiology that can occur in almost any organ system. It has neoplastic features such as local recurrence, invasive growth, and vascular invasion, leading to the possibility of malignant sarcomatous changes. The clinical presentations of colonic IPT may include abdominal pain, anemia, a palpable mass, and intestinal obstruction. A few cases of colonic IPT have been reported, but colonic IPT with pedunculated morphology is very rare. Furthermore, since it can mimic malignant polyps, understanding the endoscopic findings of colonic IPT is important for proper treatment. Herein, we present a case of colonic IPT with pseudosarcomatous changes, presenting as a large polyp, mimicking a malignant polyp in the cecum, along with a literature review.

Esophageal Stricture after Endoscopic Drainage of Esophageal Abscess as a Complication of Acute Phlegmonous Esophagitis: A Case Report / 대한소화기학회지

Esophageal abscess caused by acute phlegmonous esophagitis is rare but life-threatening. Rapid abscess drainage is an important part of the treatment, and endoscope-assisted intra-luminal abscess drainage is frequently performed. Although endoscopic drainage is less invasive than surgery, it has the potential to cause esophageal stricture as a complication. We present a rare case of esophageal stricture as a complication of intra-luminal drainage and evaluate a method to minimize the incidence of esophageal stricture complications.

Olmesartan-associated Enteropathy with Acute Kidney Injury / 대한소화기학회지

Olmesartan, a recently introduced angiotensin II receptor blocker for hypertension, has been reported to cause drug-induced small bowel enteropathy. The diagnosis of olmesartan-associated enteropathy (OAE) needs clinical suspicion and the exclusion of coeliac disease, as it mimics coeliac sprue. Once diagnosed, it can be completely cured with the discontinuation of olmesartan. However, due to the extremely low incidence of OAE in Korea, clinical suspicion and diagnosis may be a challenge. The authors report the first case of OAE presenting with chronic diarrhea and acute kidney injury in Korea.

Endoscopic Features of Submucosal Invasion in Undifferentiated-type Early Gastric Cancer Less than 20 mm in Size without Ulceration

Background/Aims@#The prediction of invasion depth is important to decide the treatment modality for undifferentiated-type early gastric cancer (EGC) less than 20 mm in size without ulceration. We aimed to identify the endoscopic features associated with submucosal invasion in undifferentiated-type EGC that meet the criteria of size and ulcer status. @*Methods@#A total of 120 patients with undifferentiated-type EGC who underwent endoscopic submucosal dissection (ESD) or gastrectomy between August 2008 and December 2017 were enrolled and reviewed retrospectively. All lesions met the ESD indications except for the invasion depth. We analyzed the endoscopic features of the tumors before resection and invasion depth after resection. @*Results@#There were 97 mucosal and 23 submucosal cancer lesions. Multivariable analysis revealed that the polypoid (OR, 90.8; 95% CI, 3.5~2,346.2) or elevated (OR, 5.0; 95% CI, 1.2~21.3) types, deep depression (OR, 76.0; 95% CI, 4.5~1,284.6), and upper (OR, 22.7; 95% CI, 3.0~170.8) or middle location (OR, 10.3; 95% CI, 1.9~55.4) were significant risk factors of submucosal invasion. @*Conclusions@#The treatment modality for undifferentiated-type EGC of the polypoid/elevated type or with deep depression located in the upper two-thirds of the stomach should be carefully considered, even if the tumor size and ulcer status meet the ESD indications.

Tumor grade 2 as the independent predictor for lymph node metastasis in 10–20 mm sized rectal neuroendocrine tumor

Purpose@#Rectal neuroendocrine tumors (NETs) <10 mm are endoscopically resected, while those ≥20 mm are treated with radical surgical resection. The choice of treatment for 10–20 mm sized rectal NETs remains controversial. This study aimed to verify factors predicting lymph node metastasis (LNM) of 10–20 mm sized rectal NET and utilize them to decide upon the treatment strategy. @*Methods@#Twenty-eight patients with 10–20 mm sized rectal NETs treated at Pusan National University Yangsan Hospital from January 2009 to September 2020 were divided into LNM (+) and LNM (–) groups, and their respective data were analyzed. @*Results@#Seven patients (25%) had LNM while 21 patients (75%) did not. Endorectal ultrasound findings showed tumor size was significantly larger in the LNM (+) than in the LNM (–) group (15 mm vs. 10 mm, P=0.018); however, pathologically, there was no significant difference in tumor size (13 mm vs. 11 mm, P=0.109). The mitotic count (P=0.011), Ki-67 index (P=0.008), and proportion of tumor grade 2 patients (5 cases, 71% vs. 1 case, 5%; P=0.001) were significantly higher in the LNM (+) group. In multivariate analysis, tumor grade 2 was the independent factor predicting LNM (odds ratio, 61.32; 95% confidence interval, 3.17–1,188.64; P=0.010). @*Conclusion@#Tumor grade 2 was the independent factor predicting LNM in 10–20 mm sized rectal NETs. Therefore, it could be considered as the meaningful factor in determining whether radical resection is necessary.

Endoscopic Features of Submucosal Invasion in Undifferentiated-type Early Gastric Cancer Less than 20 mm in Size without Ulceration

Background/Aims@#The prediction of invasion depth is important to decide the treatment modality for undifferentiated-type early gastric cancer (EGC) less than 20 mm in size without ulceration. We aimed to identify the endoscopic features associated with submucosal invasion in undifferentiated-type EGC that meet the criteria of size and ulcer status. @*Methods@#A total of 120 patients with undifferentiated-type EGC who underwent endoscopic submucosal dissection (ESD) or gastrectomy between August 2008 and December 2017 were enrolled and reviewed retrospectively. All lesions met the ESD indications except for the invasion depth. We analyzed the endoscopic features of the tumors before resection and invasion depth after resection. @*Results@#There were 97 mucosal and 23 submucosal cancer lesions. Multivariable analysis revealed that the polypoid (OR, 90.8; 95% CI, 3.5~2,346.2) or elevated (OR, 5.0; 95% CI, 1.2~21.3) types, deep depression (OR, 76.0; 95% CI, 4.5~1,284.6), and upper (OR, 22.7; 95% CI, 3.0~170.8) or middle location (OR, 10.3; 95% CI, 1.9~55.4) were significant risk factors of submucosal invasion. @*Conclusions@#The treatment modality for undifferentiated-type EGC of the polypoid/elevated type or with deep depression located in the upper two-thirds of the stomach should be carefully considered, even if the tumor size and ulcer status meet the ESD indications.

Tumor grade 2 as the independent predictor for lymph node metastasis in 10–20 mm sized rectal neuroendocrine tumor

Purpose@#Rectal neuroendocrine tumors (NETs) <10 mm are endoscopically resected, while those ≥20 mm are treated with radical surgical resection. The choice of treatment for 10–20 mm sized rectal NETs remains controversial. This study aimed to verify factors predicting lymph node metastasis (LNM) of 10–20 mm sized rectal NET and utilize them to decide upon the treatment strategy. @*Methods@#Twenty-eight patients with 10–20 mm sized rectal NETs treated at Pusan National University Yangsan Hospital from January 2009 to September 2020 were divided into LNM (+) and LNM (–) groups, and their respective data were analyzed. @*Results@#Seven patients (25%) had LNM while 21 patients (75%) did not. Endorectal ultrasound findings showed tumor size was significantly larger in the LNM (+) than in the LNM (–) group (15 mm vs. 10 mm, P=0.018); however, pathologically, there was no significant difference in tumor size (13 mm vs. 11 mm, P=0.109). The mitotic count (P=0.011), Ki-67 index (P=0.008), and proportion of tumor grade 2 patients (5 cases, 71% vs. 1 case, 5%; P=0.001) were significantly higher in the LNM (+) group. In multivariate analysis, tumor grade 2 was the independent factor predicting LNM (odds ratio, 61.32; 95% confidence interval, 3.17–1,188.64; P=0.010). @*Conclusion@#Tumor grade 2 was the independent factor predicting LNM in 10–20 mm sized rectal NETs. Therefore, it could be considered as the meaningful factor in determining whether radical resection is necessary.

Human kidney organoids model the tacrolimus nephrotoxicity and elucidate the role of autophagy

Background/Aims@#Tacrolimus has been used as an immunosuppressive agent in organ transplantation. Despite the therapeutic benefits, tacrolimus’s use is limited due to its nephrotoxicity. To reduce tacrolimus nephrotoxicity, effective humanized experimental models may be helpful. Here, we modeled tacrolimus nephrotoxicity using kidney organoids derived from human inducible pluripotent stem cells (iPSCs) in vitro. @*Methods@#Kidney organoids were differentiated from the CMC11 iPSC cell line, re-seeded in 96-well plates, and treated with tacrolimus at doses of 0, 30, or 60 μM for 24 hours. This in vitro model was compared to a mouse model of tacrolimus nephrotoxicity and the associated mechanisms were investigated. @*Results@#The size of the kidney organoids and cell viability decreased in dose-dependent manners after treatment with tacrolimus. The number of tubular cells decreased with a loss of polarity, similar to the effects seen in mouse tacrolimus nephrotoxicity. Ultrastructural analysis showed numerous vacuoles in the proximal tubular cells of the kidney organoids treated with tacrolimus. Tacrolimus treatment induced oxidative stress and mitochondrial dysfunction, and autophagic activity was enhanced in the kidney organoids. Rapamycin, an autophagy inducer, accelerated cell death in the kidney organoid model of tacrolimus nephrotoxicity, which was attenuated by treatment with 3-methyladenine, an autophagy inhibitor. These findings indicate that the augmentation of autophagy by rapamycin treatment accelerated tacrolimus nephrotoxicity. @*Conclusions@#Our data suggest that human kidney organoids are an effective in vitro model of tacrolimus nephrotoxicity and that autophagy plays a critical role in tacrolimus nephrotoxicity.

Clinical Features and Prognosis of Patients with Primary Intestinal B-cell Lymphoma Treated with Chemotherapy with or without Surgery / 대한소화기학회지

Background/Aims@#This multicenter study reviewed the clinical features and prognosis according to the primary site of involvement and the treatment modality in patients with B-cell primary intestinal lymphoma (PIL). @*Methods@#Among 125 consecutive patients diagnosed with PIL, 100 patients were analyzed. @*Results@#The median age was 59 years, and the male to female ratio was 1.86:1. Diffuse large B-cell lymphoma (66/100, 66.0%) was the most common histological subtype. The estimated 5-year survival rate (5-YSR) was 48.5%. The 5-YSR was similar regardless of the type of primary treatment (chemotherapy alone vs. surgery/chemotherapy, 50.7 vs. 45.3%, p=0.582). A comparison of the survival according to the primary site of involvement revealed a 5-YSR of 32.5% (p=0.027), 64.3% (reference), 46.5% (p=0.113), and 49.8% (p=0.024) for the small intestine, ileocecal region, large intestine, and multiple sites, respectively. Multivariate analysis, however, revealed a low hemoglobin level, advanced Ann Arbor stage, and aggressive histological type to be independent prognostic factors for shorter survival but not ileocecal region involvement. @*Conclusions@#The Ann Arbor stage, hemoglobin level, and histological type were independent prognostic factors for survival, while the primary site of involvement and treatment modality did not affect the prognosis in patients with B-cell PIL.

Endoscopic Removal of Gastric Lipoma with Hemorrhage Using Endoscopic Submucosal Dissection / 대한내과학회지

Most upper gastrointestinal lipomas occur in the duodenal second portion, and gastric lipomas are rare. Most lipomas are usually asymptomatic, but symptoms such as abdominal pain, intussusception, ulceration, and intestinal obstruction may occur depending on the size and location and, rarely, can cause bleeding. Endoscopic polypectomy, endoscopic mucosal resection, and surgical resection are the treatments of choice for lipomas with intestinal obstruction or bleeding. Upper gastrointestinal bleeding from lipoma is mostly of duodenal origin and very rarely from the stomach. Here, we report a case of successful treatment of gastric lipoma with massive bleeding by endoscopic resection.

Clinical outcomes of infection-related hospitalization in incident peritoneal dialysis patients

Background@#Infection is the second leading cause of death in patients undergoing long-term dialysis. Peritoneal dialysis (PD) is associated with an increased risk of infection-related hospitalization (IRH) when compared with hemodialysis. In this study, we investigated the influence of IRH on clinical outcomes in incident PD patients. @*Methods@#In total, 583 incident PD patients were selected from the Clinical Research Center Registry for End-Stage Renal Disease, a nationwide multicenter prospective observational cohort study in Korea. Incident PD patients who had been hospitalized for infection-related diseases were defined as the IRH group. The primary outcome was all-cause mortality and the secondary outcome was technical failure. The median follow-up period was 29 months. @*Results@#Seventy-three PD patients (12.5%) were categorized in the IRH group. Multivariable logistic regression analysis showed that diabetes mellitus was a significant independent predictor for IRH (odds ratio, 2.43; 95% confidence interval [CI], 1.12 to 5.29; P = 0.007). The most common causes of IRH were peritonitis (63.0%) and respiratory tract infection (9.6%). Multivariable Cox proportional hazard model analysis showed that IRH was a significant independent risk factor for all-cause mortality (hazard ratio [HR], 2.51; 95% CI, 1.12 to 5.62; P = 0.026) and for the technical failure of PD (HR, 3.23; 95% CI, 1.90 to 5.51; P < 0.001). @*Conclusion@#Our data showed that after initiation of PD, IRH was significantly associated with higher risk of all-cause mortality and technical failure.

Usefulness and Complications of Needle Knife Fistulotomy as a Rescue Procedure in Patients with Pancreaticobiliary Disease / 대한소화기학회지

Background/Aims@#Needle knife fistulotomy (NKF) is a technique to facilitate pancreatic and biliary duct access during ERCP. The double-guidewire technique (DGT) is also used in cases of difficult cannulation, but it can increase the incidence of post-ERCP-pancreatitis (PEP). This study examined the success and complication rates of NKF after unsuccessful standard cannulation or DGT in patients with pancreaticobiliary disease. @*Methods@#The data of 209 patients who received NKF as a rescue procedure between January 2009 and December 2016 were reviewed retrospectively. The cannulation success and complication rates were assessed. @*Results@#The overall cannulation success rate was 90.4%. The success rates of patients who received NKF after standard cannulation or DGT were similar (82.6% [142/172] and 73.0% [27/37], respectively, p=0.179). Furthermore, there was no significant difference in the incidence of procedure-related adverse events between the two groups (10.5% [18/172] and 16.2% [6/37], respectively, p=0.391). Endoscopic retrograde pancreatic drainage (ERPD) insertion decreased the incidence of PEP (0% [0/16] in ERPD and 14.6% [19/130] in non-ERPD, p=0.132) among patients who received PD cannulation. @*Conclusions@#NKF is an effective and safe method that can be considered for rescue management after the initial failure of standard cannulation or DGT. NKF following standard cannulation can be preferred over NKF following DGT because of the higher success rate and the lower rate of pancreatitis, but the difference was not significant. PD stenting in patients at high risk of PEP can be considered to decrease pancreatitis.

Endoscopic Diagnosis of Nonpedunculated Dysplasia during Surveillance of Ulcerative Colitis: A Survey-Based Multinational Study

Background/Aims@#Endoscopic diagnosis of dysplasia or colitic cancer in patients with ulcerative colitis (UC) is more challenging than that of colorectal neoplasia in non-colitic patients. We aimed to evaluate the accuracy of the endo-scopic diagnosis of “nonpedunculated” dysplasia or colitic cancer in UC patients. @*Methods@#Ten endoscopists from four countries were surveyed using photographs of 61 histologi-cally confirmed dysplastic or non-dysplastic lesions retrieved from the UC registry database of Asan Medical Center. The participants provided their assessment based on the given photographs and their intention to perform biopsy. @*Results@#The overall diagnostic performance of the 10 participants is summarized as follows: sensitivity of 88.2% (95% confidence interval [CI], 84.3% to 91.5%), specificity of 34.8% (95% CI, 29.1% to 40.8%), positive predictive value of 63.0% (95% CI, 60.8% to 65.2%), negative predictive value of 70.2% (95% CI, 62.7% to 76.6%), and accuracy of 64.6% (95% CI, 60.7% to 68.4%). The interobserver agreement on the inten-tion to perform a biopsy was poor (Fleiss kappa=0.169). Of the three endoscopic characteristics of the lesions, includ-ing ulceration, distinctness of the borders, and pit patterns, only neoplastic pit patterns were significantly predictive of dysplasia (odds ratio, 3.710; 95% CI, 2.001 to 6.881). The diagnostic sensitivity and specificity of neoplastic pit patterns were 68.2% (95% CI, 63.0% to 73.2%) and 63.3% (95% CI,57.3% to 69.1%), respectively. @*Conclusions@#Diagnostic per-formance based on the endoscopist’s intention to perform a biopsy for nonpedunculated potentially dysplastic lesions in UC patients was suboptimal according to this survey-based study.

Endoscopic Removal of Gastric Lipoma with Hemorrhage Using Endoscopic Submucosal Dissection / 대한내과학회지

Most upper gastrointestinal lipomas occur in the duodenal second portion, and gastric lipomas are rare. Most lipomas are usually asymptomatic, but symptoms such as abdominal pain, intussusception, ulceration, and intestinal obstruction may occur depending on the size and location and, rarely, can cause bleeding. Endoscopic polypectomy, endoscopic mucosal resection, and surgical resection are the treatments of choice for lipomas with intestinal obstruction or bleeding. Upper gastrointestinal bleeding from lipoma is mostly of duodenal origin and very rarely from the stomach. Here, we report a case of successful treatment of gastric lipoma with massive bleeding by endoscopic resection.

Clinical outcomes of infection-related hospitalization in incident peritoneal dialysis patients

Background@#Infection is the second leading cause of death in patients undergoing long-term dialysis. Peritoneal dialysis (PD) is associated with an increased risk of infection-related hospitalization (IRH) when compared with hemodialysis. In this study, we investigated the influence of IRH on clinical outcomes in incident PD patients. @*Methods@#In total, 583 incident PD patients were selected from the Clinical Research Center Registry for End-Stage Renal Disease, a nationwide multicenter prospective observational cohort study in Korea. Incident PD patients who had been hospitalized for infection-related diseases were defined as the IRH group. The primary outcome was all-cause mortality and the secondary outcome was technical failure. The median follow-up period was 29 months. @*Results@#Seventy-three PD patients (12.5%) were categorized in the IRH group. Multivariable logistic regression analysis showed that diabetes mellitus was a significant independent predictor for IRH (odds ratio, 2.43; 95% confidence interval [CI], 1.12 to 5.29; P = 0.007). The most common causes of IRH were peritonitis (63.0%) and respiratory tract infection (9.6%). Multivariable Cox proportional hazard model analysis showed that IRH was a significant independent risk factor for all-cause mortality (hazard ratio [HR], 2.51; 95% CI, 1.12 to 5.62; P = 0.026) and for the technical failure of PD (HR, 3.23; 95% CI, 1.90 to 5.51; P < 0.001). @*Conclusion@#Our data showed that after initiation of PD, IRH was significantly associated with higher risk of all-cause mortality and technical failure.

Paroxysmal Nocturnal Hemoglobinuria Presenting with Chronic Abdominal Pain and Iron Deficiency Anemia / 대한내과학회지

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired disorder of hematopoietic stem cells characterized by chronic intravascular hemolysis, nocturnal hemoglobinuria, thromboembolic events and secondary bone marrow failure caused by uncontrolled complement activation. Generally, chronic abdominal pain and iron deficiency anemia are considered typical symptoms of gastrointestinal diseases, but are also common in PNH. We report a case of PNH presenting with chronic abdominal pain and iron deficiency anemia, along with a relevant literature review.

14-3-3γ Haploinsufficient Mice Display Hyperactive and Stress-sensitive Behaviors

14-3-3γ plays diverse roles in different aspects of cellular processes. Especially in the brain where 14-3-3γ is enriched, it has been reported to be involved in neurological and psychiatric diseases (e.g. Williams-Beuren syndrome and Creutzfeldt-Jakob disease). However, behavioral abnormalities related to 14-3-3γ deficiency are largely unknown. Here, by using 14-3-3γ deficient mice, we found that homozygous knockout mice were prenatally lethal, and heterozygous mice showed developmental delay relative to wild-type littermate mice. In addition, in behavioral analyses, we found that 14-3-3γ heterozygote mice display hyperactive and depressive-like behavior along with more sensitive responses to acute stress than littermate control mice. These results suggest that 14-3-3γ levels may be involved in the developmental manifestation of related neuropsychiatric diseases. In addition, 14-3-3γ heterozygote mice may be a potential model to study the molecular pathophysiology of neuropsychiatric symptoms.

Clinical comparison of low-volume agents (oral sulfate solution and sodium picosulfate with magnesium citrate) for bowel preparation: the EASE study

BACKGROUND/AIMS: This study compared the efficacy, compliance, and safety of bowel preparation between sodium picosulfate with magnesium citrate (SPMC) and oral sulfate solution (OSS). METHODS: A prospective randomized multicenter study was performed. Split preparation methods were performed in both groups; the SPMC group, 2 sachets on the day before, and 1 sachet on the day of the procedure, the OSS group, half of the OSS with 1 L of water on both the day before and the day of the procedure. The adenoma detection rate (ADR), adequacy of bowel preparation using the Boston Bowel Preparation Scale (BBPS) score, patient satisfaction on a visual analog scale (VAS), and safety were compared between the 2 groups. RESULTS: This study analyzed 229 patients (121 in the SPMC group and 108 in the OSS group). ADR showed no differences between 2 groups (51.7% vs. 41.7%, P>0.05). The mean total BBPS score (7.95 vs. 8.11, P>0.05) and adequate bowel preparation rate (94.9% vs. 96.3%, P>0.05) were similar between the 2 groups. The mean VAS score for taste (7.62 vs. 6.87, P=0.006) was significantly higher in the SPMC group than in the OSS group. There were no significant differences in any other safety variables between the 2 groups except nausea symptom (36.1% vs. 20.3%, P=0.008). CONCLUSIONS: Bowel preparation for colonoscopy using low volume OSS and SPMC yielded similar ADRs and levels of efficacy. SPMC had higher levels of satisfaction for taste and feeling than did OSS.