Dr. Wei was born and raised in Taipei, Taiwan. He went to Stanford for his undergraduate studies in Biology and earned his medical degree at Weill Cornell Medical College. Unable to stay far from the Bay Area, he returned to Stanford where he completed his residency in internal medicine and subsequently his fellowship in gastroenterology. Dr. Wei has specific interests in colorectal cancer and Barrett’s esophagus surveillance as well as reflux diagnosis and management. He has an interest in endoscopic resection of large polyps and had received training under Dr. Shai Friedland, a world expert in this field. Dr. Wei work focuses on evaluating new tools, technologies and techniques in gastrointestinal cancer surveillance and management. He has been involved in running several trials in endoscopic management of polyps and evaluating artificial intelligence applications in gastroenterology. His work has been published in American Journal of Gastroenterology, Gastrointestinal Endoscopy, Clinical Endoscopy, VideoGIE, and Digestive Diseases and Sciences. He was formerly an Associate Editor for the ACG Case Report Journal (2020-2022) and was on the Board of the Northern California Society of Clinical Gastroenterology. When not in clinic or in endoscopy, Dr. Wei enjoys spending time with his family. He and his family enjoy traveling and exploring new restaurants.

Clinical Focus

  • Gastroenterology & Hepatology
  • Gastroenterology

Academic Appointments

Professional Education

  • Board Certification: American Board of Internal Medicine, Gastroenterology (2022)
  • Fellowship: Stanford University Gastroenterology Fellowship (2022) CA
  • Board Certification: American Board of Internal Medicine, Internal Medicine (2019)
  • Residency: Stanford University Internal Medicine Residency (2019) CA
  • Medical Education: Weill Cornell Medical College (2016) NY
  • M.D., Weill Cornell Medical College
  • B.S., Stanford University

Community and International Work

  • EPA Dream Center


    Bay Area

    Ongoing Project


    Opportunities for Student Involvement


All Publications

  • Multicenter evaluation of recurrence in endoscopic submucosal dissection and endoscopic mucosal resection in the colon: A Western perspective. World journal of gastrointestinal endoscopy Wei, M. T., Zhou, M. J., Li, A. A., Ofosu, A., Hwang, J. H., Friedland, S. 2023; 15 (6): 458-468


    BACKGROUND: While colon endoscopic mucosal resection (EMR) is an effective technique, removal of larger polyps often requires piecemeal resection, which can increase recurrence rates. Endoscopic submucosal dissection (ESD) in the colon offers the ability for en bloc resection and is well-described in Asia, but there are limited studies comparing ESD vs EMR in the West.AIM: To evaluate different techniques in endoscopic resection of large polyps in the colon and to identify factors for recurrence.METHODS: The study is a retrospective comparison of ESD, EMR and knife-assisted endoscopic resection performed at Stanford University Medical Center and Veterans Affairs Palo Alto Health Care System between 2016 and 2020. Knife-assisted endoscopic resection was defined as use of electrosurgical knife to facilitate snare resection, such as for circumferential incision. Patients ≥ 18 years of age undergoing colonoscopy with removal of polyp(s) ≥ 20 mm were included. The primary outcome was recurrence on follow-up.RESULTS: A total of 376 patients and 428 polyps were included. Mean polyp size was greatest in the ESD group (35.8 mm), followed by knife-assisted endoscopic resection (33.3 mm) and EMR (30.5 mm) (P < 0.001). ESD achieved highest en bloc resection (90.4%) followed by knife-assisted endoscopic resection (31.1%) and EMR (20.2%) (P < 0.001). A total of 287 polyps had follow-up (67.1%). On follow-up analysis, recurrence rate was lowest in knife-assisted endoscopic resection (0.0%) and ESD (1.3%) and highest in EMR (12.9%) (P = 0.0017). En bloc polyp resection had significantly lower rate of recurrence (1.9%) compared to non-en bloc (12.0%, P = 0.003). On multivariate analysis, ESD (in comparison to EMR) adjusted for polyp size was found to significantly reduce risk of recurrence [adjusted hazard ratio 0.06 (95%CI: 0.01-0.57, P = 0.014)].CONCLUSION: In our study, EMR had significantly higher recurrence compared to ESD and knife-assisted endoscopic resection. We found factors including resection by ESD, en bloc removal, and use of circumferential incision were associated with significantly decreased recurrence. While further studies are needed, we have demonstrated the efficacy of ESD in a Western population.

    View details for DOI 10.4253/wjge.v15.i6.458

    View details for PubMedID 37397977

  • Use of anchor pronged clips to close complex polyp resection defects. VideoGIE : an official video journal of the American Society for Gastrointestinal Endoscopy Wei, M. T., Friedland, S. 2023; 8 (6): 245-246


    Video 1Demonstration of anchored pronged clips to close complex polyp resection defects.

    View details for DOI 10.1016/j.vgie.2023.02.002

    View details for PubMedID 37303703

    View details for PubMedCentralID PMC10251435

  • Immunoglobulin G4-Seronegative Autoimmune Cholangiopathy With Pancreatic and Hepatic Involvement Mimicking as Primary Sclerosing Cholangitis. ACG case reports journal Achalu, S., Berry, R., Wei, M. T., Banerjee, S., Ghanouni, P., Kambham, N., Kwo, P. Y. 2023; 10 (4): e01044


    Immunoglobulin G4-seronegative autoimmune cholangiopathy is a rare cause of biliary strictures. We describe a 27-year-old man presenting with elevated liver enzymes, recurrent cholangitis/bacteremia, biliary strictures, and normal immunoglobulin G4 levels, who was initially diagnosed with primary sclerosing cholangitis, and later listed for transplantation for recurrent bacteremia. Subsequent surveillance imaging demonstrated morphologic changes consistent with biliary strictures and autoimmune pancreatitis. Initiating corticosteroids resulted in liver enzyme normalization and stricture improvement. Diagnosing seronegative autoimmune cholangiopathy remains challenging given similar presentation to primary sclerosing cholangitis. This case highlights importance of a wide differential for biliary strictures, with increased suspicion in those developing pancreatic changes in this setting.

    View details for DOI 10.14309/crj.0000000000001044

    View details for PubMedID 37091206

    View details for PubMedCentralID PMC10118323

  • Evaluation of computer aided detection during colonoscopy in the community (AI-SEE): a multicenter randomized clinical trial. The American journal of gastroenterology Wei, M. T., Shankar, U., Parvin, R., Hasan Abbas, S., Chaudhary, S., Friedlander, Y., Friedland, S. 2023


    There has been increasing interest in artificial intelligence in gastroenterology. To reduce miss rate during colonoscopy, there has been significant exploration in computer aided detection (CADe) devices. In this study, we evaluate the use of CADe in colonoscopy in community-based, non-academic practices.Between September 28, 2020 and September 24, 2021, a randomized controlled trial (AI-SEE) was performed evaluating the impact of CADe on polyp detection in 4 community-based endoscopy centers in the USA. Patients were block randomized to undergoing colonoscopy with or without CADe (EndoVigilant). Primary outcomes measured were adenomas per colonoscopy (APC) and adenomas per extraction (APE; the percentage of polyps removed that are adenomas). Secondary endpoints included serrated polyps per colonoscopy, non-adenomatous, non-serrated polyps per colonoscopy, adenoma and serrated polyp detection rate, and procedural time.A total of 769 patients were enrolled (387 with CADe), with similar patient demographics between the two groups. There was no significant difference in adenomas per colonoscopy in the CADe and non-CADe groups (0.73 vs 0.67, p=0.496). While use of CADe did not improve identification of serrated polyps per colonoscopy (0.08 vs 0.08, p=0.965), use of CADe increased identification of non-adenomatous, non-serrated polyps per colonoscopy (0.90 vs 0.51, p<0.0001), resulting in a lower APE in the CADe group. Adenoma detection rate (35.9 vs 37.2%, p=0.774) and serrated polyp detection rate (6.5 vs 6.3%, p=1.000) were similar in the CADe and non-CADe group. Mean withdrawal time was longer in the CADe compared to non-CADe group (11.7 vs 10.7 minutes, p=0.003). However, when no polyps were identified, there was similar mean withdrawal time (9.1 vs 8.8 minutes, p=0.288). There were no adverse events.Use of CADe did not result in a statistically significant difference in the number of adenomas detected. Additional studies are needed to better understand why some endoscopists derive substantial benefits from CADe and others do not. number, NCT04555135.

    View details for DOI 10.14309/ajg.0000000000002239

    View details for PubMedID 36892545

  • Subcutaneous Sweet Syndrome Successfully Treated With Ustekinumab in a Patient With Ulcerative Colitis. ACG case reports journal Hu, K. A., Shen, J., Rieger, K., Wei, M. T., Gubatan, J. 2022; 9 (11): e00881


    Ustekinumab, an inhibitor of the interleukin-12/23 pathway, received Food and Drug Administration (FDA) approval in 2019 for induction and maintenance therapy in patients with moderate-to-severe ulcerative colitis (UC). Data regarding the efficacy of ustekinumab in the treatment of extraintestinal manifestations of UC are unclear. Sweet syndrome, an acute febrile neutrophilic dermatosis, is a cutaneous manifestation of inflammatory bowel disease that parallels disease activity. In this study, we present the first case of subcutaneous Sweet syndrome with sterile osteomyelitis in a patient with UC successfully treated with ustekinumab.

    View details for DOI 10.14309/crj.0000000000000881

    View details for PubMedID 36447766

    View details for PubMedCentralID PMC9699508

  • Use of a novel dual-action clip for closure of complex endoscopic resection defects. VideoGIE : an official video journal of the American Society for Gastrointestinal Endoscopy Wei, M. T., Friedland, S. 2022; 7 (11): 389-391


    Video 1Use of dual-action clips and clips with added atraumatic teeth to close complex endoscopic resection defects.

    View details for DOI 10.1016/j.vgie.2022.08.005

    View details for PubMedID 36407049

  • Subcutaneous Sweet Syndrome Successfully Treated With Ustekinumab in Patient With Ulcerative Colitis Hu, K., Wei, M., Gubatan, J. LIPPINCOTT WILLIAMS & WILKINS. 2022: S1817-S1818
  • IgG4-Seronegative Autoimmune Cholangiopathy With Pancreatic and Hepatic Involvement Mimicking as Primary Sclerosing Cholangitis Achalu, S., Wei, M., Berry, R., Banerjee, S., Ghanouni, P., Kwo, P. LIPPINCOTT WILLIAMS & WILKINS. 2022: S1231
  • De Novo Diagnosis of Lymphocytic Colitis After SARS-CoV-2 Vaccination ACG CASE REPORTS JOURNAL Lee, P., Wei, M. T., Gubatan, J., Forgo, E., Berry, G. J., Verma, R., Friedland, S. 2022; 9 (9)
  • De Novo Diagnosis of Lymphocytic Colitis After SARS-CoV-2 Vaccination. ACG case reports journal Lee, P., Wei, M. T., Gubatan, J., Forgó, E., Berry, G. J., Verma, R., Friedland, S. 2022; 9 (9): e00849


    SARS-CoV-2 mRNA vaccines are safe and effective for most patients. Gastrointestinal complications reported after vaccination have included gastroparesis and inflammatory bowel disease flares. In this study, we present a unique case of lymphocytic colitis that occurred in a healthy middle-aged man after Moderna SARS-CoV-2 mRNA vaccination. This reveals an unexpected complication of a mRNA vaccine that presented as worsening diarrhea after vaccination in a dose-dependent pattern. Caregivers should be aware of lymphocytic colitis as a possible complication of the Moderna vaccine and monitor those patients closely for symptom resolution.

    View details for DOI 10.14309/crj.0000000000000849

    View details for PubMedID 36134123

    View details for PubMedCentralID PMC9485468

  • Randomized controlled trial investigating use of submucosal injection of EverLift in rates of complete resection of non-pedunculated 4-9mm polyps. International journal of colorectal disease Wei, M. T., Louie, C. Y., Chen, Y., Pan, J. Y., Quan, S. Y., Wong, R., Brown, R., Clark, M., Jensen, K., Lau, H., Friedland, S. 2022


    INTRODUCTION: Currently, cold snare polypectomy (CSP) without submucosal injection is recommended for removing polyps<10mm. Use of viscous submucosal agents has not been previously evaluated in CSP. We investigate the potential role of EverLift (GI Supply, Pennsylvania) in CSP.METHODS: The study is a single-center prospective randomized non-inferiority clinical trial evaluating CSP of non-pedunculated 4-9mm polyps, with or without submucosal injection of EverLift. Patients 18-80years of age presenting for colonoscopy were recruited. Eligible polyps underwent block randomization to CSP with or without EverLift. Following CSP, two biopsies were performed at the CSP site margin. The primary non-inferiority outcome was complete resection rate, defined by absence of residual polyp in the margin biopsies (non-inferiority margin-10%).RESULTS: A total of 291 eligible polyps underwent CSP, with 142 removed using EverLift. There was similar polyp size and distribution of pathology between the two groups. Overall, there was a low rate of positive margins with (1.4%) or without submucosal injection (2.8%), with no significant difference in complete resection (difference 1.28%, 95% CI:-2.66 to 5.42%), demonstrating non-inferiority of EverLift injection. Use of EverLift significantly increased CSP time (109.8 vs 38.8s, p<0.0001) and frequency of use of hemostatic clips (13.4 vs 3.6%, p=0.002).CONCLUSION: Submucosal injection of EverLift was non-inferior to CSP of 4-9mm polyps without injection and increased time for resection as well as use of hemostatic clips to control acute bleeding. Our results suggest that polypectomy of 4-9mm polyps can be safely performed without submucosal injection of EverLift.

    View details for DOI 10.1007/s00384-022-04136-4

    View details for PubMedID 35507047

  • Randomized controlled Trial Investigating cold snare aNd forceps polypectomY among small POLYPs in rates of complete resection: the TINYPOLYP Trial. The American journal of gastroenterology Wei, M. T., Louie, C. Y., Chen, Y., Pan, J. Y., Quan, S. Y., Wong, R., Brown, R., Clark, M., Jensen, K., Lau, H., Friedland, S. 2022


    BACKGROUND: Optimizing complete resection during colonoscopy is important as residual neoplastic tissue may play a role in interval cancers. The United States Multi-Society Task Force recommends diminutive (<5mm) and small (6-9mm) polyps be removed by cold snare polypectomy (CSP). However, evidence is less clear whether CSP retains significant advantage over cold forceps polypectomy (CFP) for polyps <3mm.METHODS: This study is a single-center prospective non-inferiority randomized clinical trial evaluating CFP and CSP for nonpedunculated polyps <3mm. Patients >18 years of age undergoing colonoscopy for any indication were recruited. During each colonoscopy, polyps underwent block randomization to removal with CFP or CSP. Following polypectomy, two biopsies were taken from the polypectomy margin. The primary non-inferiority outcome was complete resection rate, defined by absence of residual polyp in the margin biopsies.RESULTS: A total of 179 patients were included. Patients had similar distribution in age, sex, race/ethnicity, as well as indication of procedure. A total of 279 polyps <3mm were identified, with 138 in the CSP group and 141 in the CFP group. Mean polypectomy time was longer for CSP compared to CFP (42.3 vs 23.2 seconds, p<0.001), though a higher proportion of polyps removed by CFP were removed in more than one piece compared to CSP (15.6 vs 3.6%, p<0.001). There were positive margin biopsies in 2 cases per cohort, with complete resection rate of 98.3% in both groups. There was no significant difference in cohorts in complete resection rates (difference in complete resection rates was 0.057%, 95% CI: -4.30 to 4.53%), demonstrating non-inferiority of CFP compared to CSP.CONCLUSIONS: Use of CFP was non-inferior to CSP in the complete resection of nonpedunculated polyps <3mm. CSP required significantly more time to perform compared to CFP. CFP should be considered an acceptable alternative to CSP for removal of polyps <3mm.

    View details for DOI 10.14309/ajg.0000000000001799

    View details for PubMedID 35467557

  • Clinical evaluation of a real-time artificial intelligence-based polyp detection system: a US multi-center pilot study. Scientific reports Quan, S. Y., Wei, M. T., Lee, J., Mohi-Ud-Din, R., Mostaghim, R., Sachdev, R., Siegel, D., Friedlander, Y., Friedland, S. 2022; 12 (1): 6598


    Artificial intelligence (AI) has increasingly been employed in multiple fields, and there has been significant interest in its use within gastrointestinal endoscopy. Computer-aided detection (CAD) can potentially improve polyp detection rates and decrease miss rates in colonoscopy. However, few clinical studies have evaluated real-time CAD during colonoscopy. In this study, we analyze the efficacy of a novel real-time CAD system during colonoscopy. This was a single-arm prospective study of patients undergoing colonoscopy with a real-time CAD system. This AI-based system had previously been trained using manually labeled colonoscopy videos to help detect neoplastic polyps (adenomas and serrated polyps). In this pilot study, 300 patients at two centers underwent elective colonoscopy with the CAD system. These results were compared to 300 historical controls consisting of consecutive colonoscopies performed by the participating endoscopists within 12months prior to onset of the study without the aid of CAD. The primary outcome was the mean number of adenomas per colonoscopy. Use of real-time CAD trended towards increased adenoma detection (1.35 vs 1.07, p=0.099) per colonoscopy though this did not achieve statistical significance. Compared to historical controls, use of CAD demonstrated a trend towards increased identification of serrated polyps (0.15 vs 0.07) and all neoplastic (adenomatous and serrated) polyps (1.50 vs 1.14) per procedure. There were significantly more non-neoplastic polyps detected with CAD (1.08 vs 0.57, p<0.0001). There was no difference in≥10mm polyps identified between the two groups. A real-time CAD system can increase detection of adenomas and serrated polyps during colonoscopy in comparison to historical controls without CAD, though this was not statistically significant. As this pilot study is underpowered, given the findings we recommend pursuing a larger randomized controlled trial to further evaluate the benefits of CAD.

    View details for DOI 10.1038/s41598-022-10597-y

    View details for PubMedID 35449442

  • Cold Snare Resection of Small Colorectal Adenomas: The Second Time's a Charm. Digestive diseases and sciences Wei, M. T., Friedland, S. 2021

    View details for DOI 10.1007/s10620-021-07293-8

    View details for PubMedID 34731361

  • Over-the-Scope Clip in the Treatment of Gastrointestinal Leaks and Perforations. Clinical endoscopy Wei, M. T., Ahn, J. Y., Friedland, S. 2021; 54 (6): 798-804


    While perforations, postoperative fistulas, and leaks have traditionally led to surgical or interventional radiology consultation for management, the introduction of the over-the-scope clip has allowed increased therapeutic possibilities for endoscopists. While primarily limited to case reports and series, the over-the-scope clip successfully manages gastrointestinal bleeding, perforations, as well as postoperative leaks and fistulas. Retrospective studies have demonstrated a relatively high success rate and a low complication rate. Given the similarity to variceal banding equipment, the learning curve with the over-the-scope clip is rapid. However, given the higher risk of procedures involving the use of the over-the-scope clip, it is essential to obtain the scope in a stable position and grasp sufficient tissue with the cap using a grasping tool and/or suction. From our experience, while closure may be successful in lesions sized up to 3 cm, successful outcomes are obtained for lesions sized <1 cm. Ultimately, given the limited available data, prospective randomized trials are needed to better evaluate the utility of the over-the-scope clip in various clinical scenarios, including fistula and perforation management.

    View details for DOI 10.5946/ce.2021.250

    View details for PubMedID 34872236

  • Use of the Rigidizing Overtube in Assisting Endoscopic Submucosal Dissection Among Patients With Ulcerative Colitis Wei, M. T., Hwang, J., Friedland, S. LIPPINCOTT WILLIAMS & WILKINS. 2021: S880
  • Evaluation of EverLift in the Performance of Cold Snare Polypectomy (CSP) for 4-9mm Polyps Wei, M. T., Louie, C., Chen, Y., Pan, J. Y., Quan, S. Y., Wong, R., Brown, R., Clark, M., Jensen, K., Lau, H., Friedland, S. LIPPINCOTT WILLIAMS & WILKINS. 2021: S130-S131
  • Provider Perspectives on HCC Surveillance in Patients With Cirrhosis: Community Provider Perspectives Matter CLINICAL GASTROENTEROLOGY AND HEPATOLOGY [Anonymous] 2021; 19 (9): 1991
  • Evaluation of ethnic influence in the application of a hepatocellular carcinoma predictive model for chronic hepatitis C. Journal of medical virology Wei, M. T., Le, M. H., Landis, C., Trinh, H., Wong, G., Le, A., Zhang, J., Cheung, R., Nguyen, M. H. 2021


    Currently, there is no well-established algorithm predicting HCC development in untreated HCV patients. We aimed to validate an algorithm (REVEAL-HCV: age, AST, ALT, HCV RNA, HCV genotype, and cirrhosis) developed in Taiwanese patients.We analyzed 1,381 (50.1% White, 14.7% Hispanic, 13.8% Asian of diverse origin, and 7.8% African-American) adult treatment-naïve HCV patients (no viral co-infection, no HCC within 6 months) at 4 U.S. and one Hong Kong centers (11/1994-10/2017).Compared to the non-Asian cohort, the Asian cohort had higher percentage of patients in the low-risk group (46.1% vs. 26.1%) and lower percentage in the high-risk group (12.0% vs. 20.3%, p<0.01). Overall, 5-year HCC incidence were 1.75%, 4.71%, and 24.4% for low, medium and high-risk patients, respectively (p<0.0001). For the overall cohort, AUROC for HCC prediction were 0.83 (95% CI: 0.72-0.93), 0.82 (95% CI: 0.75-0.88), and 0.84 (95% CI: 0.77-0.89) for 1-year, 3-year and 5-year HCC risk, respectively. There was slightly lower AUROC for Asian compared to the non-Asian cohort at 3 years (0.75 vs. 0.83) and 5 years (0.78 vs. 0.84), though this was not statistically significant. In multivariable analysis, we found male sex, presence of metabolic syndrome as well as the risk score categories to be independently associated with HCC but not ethnicity.The REVEAL-HCV risk score has good validity for both Asian and non-Asian populations. Further studies should consider additional factors such as sex, metabolic syndrome and treatment status. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1002/jmv.27168

    View details for PubMedID 34219250

  • Artificial intelligence applications in inflammatory bowel disease: Emerging technologies and future directions. World journal of gastroenterology Gubatan, J. n., Levitte, S. n., Patel, A. n., Balabanis, T. n., Wei, M. T., Sinha, S. R. 2021; 27 (17): 1920-1935


    Inflammatory bowel disease (IBD) is a complex and multifaceted disorder of the gastrointestinal tract that is increasing in incidence worldwide and associated with significant morbidity. The rapid accumulation of large datasets from electronic health records, high-definition multi-omics (including genomics, proteomics, transcriptomics, and metagenomics), and imaging modalities (endoscopy and endomicroscopy) have provided powerful tools to unravel novel mechanistic insights and help address unmet clinical needs in IBD. Although the application of artificial intelligence (AI) methods has facilitated the analysis, integration, and interpretation of large datasets in IBD, significant heterogeneity in AI methods, datasets, and clinical outcomes and the need for unbiased prospective validations studies are current barriers to incorporation of AI into clinical practice. The purpose of this review is to summarize the most recent advances in the application of AI and machine learning technologies in the diagnosis and risk prediction, assessment of disease severity, and prediction of clinical outcomes in patients with IBD.

    View details for DOI 10.3748/wjg.v27.i17.1920

    View details for PubMedID 34007130

    View details for PubMedCentralID PMC8108036

  • Early Esophageal Cancer: What the Gastroenterologist Needs to Know. Gastroenterology clinics of North America Wei, M. T., Friedland, S. 2021; 50 (4): 791-808


    Endoscopic findings in early esophageal cancer are often subtle and require careful inspection and meticulous endoscopic examination. When dysplasia is suspected, we recommend performing 1 or 2 targeted biopsies of the abnormal area and review with a pathologist specialized in evaluating gastrointestinal diseases. In the case of adenocarcinoma, after resection of any visible cancer, residual Barrett's can be treated by ablation. Endoscopic resection can offer the opportunity for patients to avoid surgery. Further studies are needed to evaluate the optimal management of circumferential and near-circumferential lesions as well as tools and techniques to facilitate the performance of endoscopic submucosal dissection and endoscopic mucosal resection.

    View details for DOI 10.1016/j.gtc.2021.07.004

    View details for PubMedID 34717871

  • Use of a rigidizing overtube for altered-anatomy ERCP. VideoGIE : an official video journal of the American Society for Gastrointestinal Endoscopy Wei, M. T., Friedland, S., Watson, R. R., Hwang, J. H. 2020; 5 (12): 664–66

    View details for DOI 10.1016/j.vgie.2020.08.003

    View details for PubMedID 33319136

  • Use of a rigidizing overtube to complete an incomplete colonoscopy. VideoGIE : an official video journal of the American Society for Gastrointestinal Endoscopy Wei, M. T., Hwang, J. H., Watson, R., Friedland, S. 2020; 5 (11): 583–85

    View details for DOI 10.1016/j.vgie.2020.06.014

    View details for PubMedID 33204926

  • Gut Dysthymia: Paraneoplastic Chronic Watery Diarrhea. Digestive diseases and sciences Wei, M. T., Scapa, J., Bingham, D., Triadafilopoulos, G. 2020

    View details for DOI 10.1007/s10620-020-06058-z

    View details for PubMedID 31965390

  • Provider Perspectives on HCC Surveillance in Patients With Cirrhosis: Community Provider Perspectives Matter. Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association Wei, M. T., Nguyen, M. H. 2020

    View details for DOI 10.1016/j.cgh.2020.10.050

    View details for PubMedID 33248098

  • Novel rigidizing overtube for colonoscope stabilization and loop prevention (with video). Gastrointestinal endoscopy Wei, M. T., Hwang, J. H., Watson, R. R., Park, W. n., Friedland, S. n. 2020


    Loop formation can impede scope advancement, destabilize the tip and cause pain. Strategies to mitigate looping include torque-based reduction maneuvers, variable stiffness shafts and abdominal splinting. In some cases, these strategies are insufficient and there is need for novel instruments. Loop formation is of particular concern in colonoscopy, but it can also impact performance of other endoscopic procedures such as enteroscopy and altered-anatomy ERCP. In this case series we demonstrate the utility of a novel rigidizing overtube (Pathfinder, Neptune Medical, Burlingame, Calif, USA) in colonoscopy and other endoscopic procedures where loop management is critical.We describe our initial experience with the Pathfinder overtube in 29 patients. The overtube is 85 centimeters long and can accommodate a pediatric colonoscope. In its native state, the overtube is extremely flexible. Once the overtube is advanced to the desired location, application of a vacuum to the device causes the device to become 15 times stiffer. The endoscope can then be advanced through the overtube without loop formation in the region that the overtube traverses.The overtube was used in 29 patients to assist with difficult procedures. The patients were predominantly male (N=18; 62.1%), with median age 66 (interquartile range 57-72). One patient received an upper endoscopy (3.4%), 24 received colonoscopy (82.8%), and 4 received enteroscopy (13.8%). The overtube was used in 12 for incomplete colonoscopy (41.4%), 6 for depth (20.7%), and 11 for stability (37.9%). Colonoscopy was performed in the setting of screening (N=3), surveillance given polyp history (N=7), referrals for polyp removal (N=10), workup of iron deficiency anemia (N=2), and incomplete colonoscopy (N=1). The lower endoscopy cases had a median cecal intubation time of 5 minutes and had interquartile range (4.25 - 7 minutes). Enteroscopy was performed in 4 patients. (1) The distal 60 cm of the ileum was examined with a pediatric colonoscope to exclude ileitis. (2) The overtube was used to stabilize a 6 mm endoscope to traverse a tight Crohn's ileocolonic stricture. (3) Altered-anatomy ERCP was performed using an enteroscope through the overtube to reach a hepaticojejunostomy. (4) Upper enteroscopy was performed and the mid-jejunum was reached. We present 4 cases that demonstrate the use of the overtube. There were no adverse events.Initial experience with a novel rigidizing overtube suggests that this tool can be useful in colonoscopy and other endoscopic procedures that are affected by looping.

    View details for DOI 10.1016/j.gie.2020.07.054

    View details for PubMedID 32739483

  • Hepatitis B Virus Reactivation Potentiated by Biologics. Infectious disease clinics of North America Ogawa, E. n., Wei, M. T., Nguyen, M. H. 2020


    Hepatitis B virus (HBV) reactivation can be a serious complication for patients with chronic or resolved HBV infection when treated with biologics. For HBsAg-positive patients receiving biologics, the risk of HBV reactivation is moderate to high. HBsAg-negative/anti-HBc positive patients are at lower risk of HBV reactivation than HBsAg-positive patients. However, patients taking anti-CD20 agents, such as rituximab, have high risk of HBV reactivation (>10%), so antiviral prophylactic therapies are required. This review provides the different classes of biologics associated with HBV reactivation, stratifies the various reactivation risk levels by HBV status and biologic agent, and discusses management strategies.

    View details for DOI 10.1016/j.idc.2020.02.009

    View details for PubMedID 32334985

  • The Mettle to Use the Petals: Using Over-the-Scope Rings to Optimize Endoscopic Submucosal Dissection. Digestive diseases and sciences Wei, M. T., Triadafilopoulos, G. n., Friedland, S. n. 2020

    View details for DOI 10.1007/s10620-020-06596-6

    View details for PubMedID 32909123

  • What to Do When Fecal Immunochemical Test (FIT) Is Positive Following Normal Colonoscopy? Comparison of Adenoma Detection Rate (ADR) of Standard FIT-Colonoscopy and Relook Colonoscopy Wei, M., Dao, A. T., Le, A., Nguyen, T., Tran, B., Trinh, L. L., Nguyen, H. A., Nguyen, K., Levitt, B. S., Shieh, E., Goyal, T., Cheung, R., Nguyen, M. H., Trinh, H. LIPPINCOTT WILLIAMS & WILKINS. 2019: S192
  • Sustained virologic response to direct-acting antiviral therapy in patients with chronic hepatitis C and hepatocellular carcinoma: A systematic review and meta-analysis JOURNAL OF HEPATOLOGY Ji, F., Yeo, Y., Wei, M., Ogawa, E., Enomoto, M., Lee, D., Iio, E., Lubel, J., Wang, W., Wei, B., Ide, T., Preda, C., Conti, F., Minami, T., Bielen, R., Sezaki, H., Barone, M., Kolly, P., Chu, P., Virlogeux, V., Eurich, D., Henry, L., Bass, M. B., Kanai, T., Dang, S., Li, Z., Dufour, J., Zoulim, F., Andreone, P., Cheung, R. C., Tanaka, Y., Furusyo, N., Toyoda, H., Tamori, A., Nguyen, M. H. 2019; 71 (3): 473–85
  • Antiviral therapy and the development of osteopenia/osteoporosis among Asians with chronic hepatitis Bn JOURNAL OF MEDICAL VIROLOGY Wei, M. T., Le, A. K., Chang, M. S., Hsu, H., Nguyen, P., Zhang, J. Q., Wong, C., Wong, C., Cheung, R., Nguyen, M. H. 2019; 91 (7): 1288–94

    View details for DOI 10.1002/jmv.25433

    View details for Web of Science ID 000471755300014

  • Prevalence, incidence, and outcome of non-alcoholic fatty liver disease in Asia, 1999-2019: a systematic review and meta-analysis LANCET GASTROENTEROLOGY & HEPATOLOGY Li, J., Zou, B., Yeo, Y., Feng, Y., Xie, X., Lee, D., Fujii, H., Wu, Y., Kam, L. Y., Ji, F., Li, X., Chien, N., Wei, M., Ogawa, E., Zhao, C., Wu, X., Stave, C. D., Henry, L., Barnett, S., Takahashi, H., Furusyo, N., Eguchi, Y., Hsu, Y., Lee, T., Ren, W., Qin, C., Jun, D., Toyoda, H., Wong, V., Cheung, R., Zhu, Q., Nguyen, M. H. 2019; 4 (5): 389–98
  • Hospital Cirrhosis Volume and Readmission in Patients with Cirrhosis in California (vol 63, pg 2267, 2018) DIGESTIVE DISEASES AND SCIENCES Wei, M., Ford, J., Li, Q., Jeong, D., Kwong, A. J., Nguyen, M. H., Chang, M. S. 2019; 64 (5): 1392–94
  • Prevalence, incidence, and outcome of non-alcoholic fatty liver disease in Asia, 1999-2019: a systematic review and meta-analysis. The lancet. Gastroenterology & hepatology Li, J., Zou, B., Yeo, Y. H., Feng, Y., Xie, X., Lee, D. H., Fujii, H., Wu, Y., Kam, L. Y., Ji, F., Li, X., Chien, N., Wei, M., Ogawa, E., Zhao, C., Wu, X., Stave, C. D., Henry, L., Barnett, S., Takahashi, H., Furusyo, N., Eguchi, Y., Hsu, Y., Lee, T., Ren, W., Qin, C., Jun, D. W., Toyoda, H., Wong, V. W., Cheung, R., Zhu, Q., Nguyen, M. H. 2019


    BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease worldwide. Asia is a large, heterogeneous area with substantial variation in socioeconomic status and prevalence of obesity. We estimated the prevalence, incidence, and outcomes of NAFLD in the Asian population to assist stakeholders in understanding NAFLD disease burden.METHODS: We searched PubMed, EMBASE, and the Cochrane Library from database inception to Jan 17, 2019, for studies reporting NAFLD prevalence, incidence, or outcome in Asia. We included only cross-sectional and longitudinal observational studies of patients with NAFLD diagnosed by imaging, serum-based indices, or liver biopsy. Studies that included patients with overlapping liver disease or that did not screen for excess alcohol consumption were excluded. Two investigators independently screened and extracted data. The main outcomes were pooled NAFLD prevalence, incidence, and hepatocellular carcinoma incidence and overall mortality in patients with NAFLD. Summary estimates were calculated using a random-effects model. This study is registered with PROSPERO, number CRD42018088468.FINDINGS: Of 4995 records identified, 237 studies (13 044 518 participants) were included for analysis. The overall prevalence of NAFLD regardless of diagnostic method was 29·62% (95% CI 28·13-31·15). NAFLD prevalence increased significantly over time (25·28% [22·42-28·37] between 1999 and 2005, 28·46% [26·70-30·29] between 2006 and 2011, and 33·90% [31·74-36·12] between 2012 and 2017; p<0·0001). The pooled annual NAFLD incidence rate was 50·9 cases per 1000 person-years (95% CI 44·8-57·4). In patients with NAFLD, the annual incidence of hepatocellular carcinoma was 1·8 cases per 1000 person-years (0·8-3·1) and overall mortality rate was 5·3 deaths per 1000 person-years (1·5-11·4).INTERPRETATION: NAFLD prevalence in Asia is increasing and is associated with poor outcomes including hepatocellular carcinoma and death. Targeted public health strategies must be developed in Asia to target the drivers of this rising epidemic and its associated complications, especially in high-risk groups, such as older obese men.FUNDING: None.

    View details for PubMedID 30902670

  • Nonliver Comorbidities in Patients With Chronic Hepatitis B. Clinical liver disease Wei, M. T., Henry, L. n., Nguyen, M. H. 2019; 14 (3): 126–30

    View details for DOI 10.1002/cld.829

    View details for PubMedID 31632664

    View details for PubMedCentralID PMC6784802

  • Antiviral therapy and the development of osteopenia/osteoporosis among Asians with chronic hepatitis B. Journal of medical virology Wei, M. T., Le, A. K., Chang, M. S., Hsu, H. n., Nguyen, P. n., Zhang, J. Q., Wong, C. n., Wong, C. n., Cheung, R. n., Nguyen, M. H. 2019


    Recent studies have suggested a potential increase in the incidence of osteoporosis for patients receiving tenofovir disoproxil fumarate (TDF), but this issue remains controversial.Retrospective cohort study of 1,224 Asian chronic hepatitis B (CHB) patients >18 years without baseline osteopenia/osteoporosis seen at four U.S. centers from 2008-2016. Patients were categorized into three groups-treatment naive patients who initiated therapy with TDF (1) or entecavir (ETV) (2), or untreated patients (3). Patients were followed until development of osteopenia/osteoporosis or end of study.Of the 1,224 study patients, 276 were treated with TDF, 335 with ETV, and 613 were untreated. The prevalence of cirrhosis was lower for untreated patients (2.6% vs. 16.3% for TDF and 17.6% for ETV, p<0.001). The 8-year cumulative incidence rate of osteopenia/osteoporosis was 13.17% for TDF, 15.09% for ETV and 10.17% for untreated patients, with no statistically significant difference among the three groups (p=0.218). On multivariate Cox regression controlling for demographics, osteoporosis risk factors, albumin, and hepatitis B virus (HBV) DNA levels, neither TDF (adjusted HR 0.74, 95% CI: 0.34, 1.59) nor ETV (adjusted HR 0.98, 95% CI: 0.51, 1.90) were associated with increased osteopenia/osteoporosis risk compared to untreated patients.Our retrospective study suggests there is no significant increase in incidence of osteopenia/osteoporosis for CHB patients treated with TDF or ETV during median follow-up of about 4-5 years. However, further study with longer follow-up is needed as anti-HBV therapy is often lifelong or long-term and the development of osteopenia/osteoporosis can be a slow process. This article is protected by copyright. All rights reserved.

    View details for PubMedID 30776311

  • Sustained virologic response to direct-acting antiviral therapy in patients with chronic hepatitis C and hepatocellular carcinoma: A systematic review and meta-analysis. Journal of hepatology Ji, F. n., Yeo, Y. H., Wei, M. T., Ogawa, E. n., Enomoto, M. n., Lee, D. H., Iio, E. n., Lubel, J. n., Wang, W. n., Wei, B. n., Ide, T. n., Preda, C. M., Conti, F. n., Minami, T. n., Bielen, R. n., Sezaki, H. n., Barone, M. n., Kolly, P. n., Chu, P. S., Virlogeux, V. n., Eurich, D. n., Henry, L. n., Bass, M. B., Kanai, T. n., Dang, S. n., Li, Z. n., Dufour, J. F., Zoulim, F. n., Andreone, P. n., Cheung, R. C., Tanaka, Y. n., Furusyo, N. n., Toyoda, H. n., Tamori, A. n., Nguyen, M. H. 2019


    Questions remain about the effect of hepatocellular carcinoma (HCC) on response to interferon-free direct-acting antiviral (DAA) therapy for chronic hepatitis C (CHC) patients compared to those without HCC. Using a systematic review and meta-analysis approach, we aimed to investigate the effect of DAA therapy on sustained virologic response among CHC patients with active, inactive and no HCC.PubMed, Embase, Web of Science, and the Cochrane Controlled Trials Register were searched from 1/1/2013 to 9/24/2018. The pooled sustained virologic response (SVR) rates were computed using DerSimonian-Laird random-effects models.We included 49 studies from 15 countries, comprised of 3,341 HCC and 35,701 non-HCC patients. Overall, the pooled SVR was lower in HCC than in non-HCC patients (89.6%, 95% CI 86.8-92.1%, I2=79.1% vs. 93.3%, 95% CI 91.9-94.7%, I2=95.0%, P=0.0012), translating to a 4.8% (95% CI 0.2-7.4%) SVR reduction by meta-regression analysis. Also on meta-regression analyses, the largest SVR reduction (18.8%) occurred in patients with active/residual HCC vs. inactive/ablated HCC (SVR 73.1% vs. 92.6%, P=0.002). Meanwhile, HCC patients with prior liver transplant (LT) had higher SVR compared to non-LT HCC patients (P<0.001). Regarding specific DAA regimens, HCC patients treated with ledipasvir/sofosbuvir had lower SVR rates than non-HCC patients (92.6%, n=884 vs. 97.8%, n=13,141, P=0.026) but heterogeneity was high (I2=84.7%, P<0.001). For the few HCC patients treated with paritaprevir/ritonavir, ombitasvir ± dasabuvir (n=101), SVR was similar to non-HCC patient (97.2% vs. 94.8%, P=0.79). Daclatasvir/asunaprevir-treated HCC and non-HCC patients also had similar SVR rates though both were low (91.7% vs. 89.8%, P=0.66).Overall, SVR was lower in HCC compared to non-HCC patients, especially in those with active HCC though heterogeneity was high. Continued efforts are needed to aggressively screen, diagnose and treat HCC to ensure higher CHC cure rates.There are now medications ("DAAs") that can "cure" hepatitis C virus, but patients with hepatitis C and liver cancer may be less likely to achieve cure than those without liver cancer. However, liver cancer patients are also more likely to have advanced liver disease and risk factors that can decrease cure rates, so better controlled studies are needed to confirm these findings.

    View details for PubMedID 31096005

  • Increased Prevalence of Non-Alcoholic Fatty Liver Disease (NAFLD) in Asia: A Systematic Review and Meta-Analysis of 164 Studies and 1,704,963 Subjects from 13 Countries Li, J., Zou, B., Yeo, Y., Fujii, H., Lee, D., Ji, F., Ogawa, E., Feng, Y., Xie, X., Wei, M., Ren, W., Qin, C., Zhu, Q., Nguyen, M. H. WILEY. 2018: 983A
  • Distribution of Etiologies in Cirrhosis Admissions and Its Year Trend Burden in California (CA): A Population-Based Study with the Office of Statewide Health Planning and Development (OSHPD) Wei, B., Wei, M., Jeong, D., Henry, L., Cheung, R., Nguyen, M. H. WILEY. 2018: 461A
  • Hospital Cirrhosis Volume and Readmission in Patients with Cirrhosis in California. Digestive diseases and sciences Wei, M. n., Ford, J. n., Li, Q. n., Jeong, D. n., Kwong, A. J., Nguyen, M. H., Chang, M. S. 2018


    Patients with cirrhosis are at high readmission risk. Using a large statewide database, we evaluated the effect of hospital cirrhosis-related patient volume on 30-day readmissions in patients with cirrhosis.We conducted a retrospective study of the Healthcare Cost and Utilization Project State Inpatient Database for adult patients with cirrhosis, as defined by International Classification of Diseases, Ninth Revision (ICD-9) codes, hospitalized in California between 2009 and 2011. Multivariable logistic regression analysis was performed to evaluate the effect of hospital volume on 30-day readmissions.A total of 69,612 patients with cirrhosis were identified in 405 hospitals; 24,062 patients were discharged from the top 10% of hospitals (N = 41) by cirrhosis volume, and 45,550 patients in the bottom 90% (N = 364). Compared with higher-volume centers, lower-volume hospitals cared for patients with similar average Quan-Charlson-Deyo (QCD) comorbidity scores (6.54 vs. 6.68), similar proportion of hepatitis B and fatty liver disease, lower proportion of hepatitis C (34.8 vs. 41.5%) but greater proportion of alcoholic liver disease (53.1 vs. 47.4%). Multivariable logistic regression analysis demonstrated admission to a lower-volume hospital did not predict 30-day readmission (odds ratio [OR] 0.97, 95% confidence interval [CI] 0.92-1.01) after adjusting for sociodemographics, QCD score, cirrhosis severity, and hospital characteristics. Instead, liver transplant center status significantly decreased the risk of readmission (OR 0.87, 95% CI 0.80-0.94). Ascites, hepatic encephalopathy, hepatocellular carcinoma, higher QCD, and presence of alcoholic liver disease and hepatitis C were also independent predictors.Readmissions within 30 days were common among patients with cirrhosis hospitalized in California. While hospital cirrhosis volume did not predict 30-day readmissions, liver transplant center status was protective of readmissions. Medically complicated patients with cirrhosis at hospitals without liver transplant centers may benefit from additional support to prevent readmission.

    View details for PubMedID 29457210

  • Is antiviral treatment for chronic hepatitis B (CHB) in Asian patients associated with osteopenia/osteoporosis? A comparison study of tenofovir (TDF), entecavir (ETV) and untreated (UTx) patients Wei, M., Le, A. K., Nguyen, P., Zhang, J. Q., Wong, C., Wong, C., Chang, M., Nguyen, M. H. WILEY. 2017: 516A–517A
  • Hepatocellular carcinoma decreases the effectiveness of hepatitis C antiviral treatment: does direct-acting antiviral regimens matter? Hepatology (Baltimore, Md.) Ji, F. n., Yeo, Y. H., Wei, M. T., Wei, B. n., Dang, S. n., Li, Z. n., Nguyen, M. H. 2017

    View details for PubMedID 29194694

  • Tenofovir alafenamide as compared to tenofovir disoproxil fumarate in the management of chronic hepatitis B with recent trends in patient demographics. Expert review of gastroenterology & hepatology Hsu, Y. C., Wei, M. T., Nguyen, M. H. 2017


    Tenofovir alafenamide (TAF) has recently been approved for chronic hepatitis B (CHB). It is more stable than tenofovir disoproxil fumarate (TDF) in the plasma and can provide similar efficacy with lower circulating concentration in patients with hepatitis B virus (HBV) infection. Areas covered: This synopsis will review the current anti-HBV standard practice and the changing epidemiology of CHB, specifically the controversies surrounding the renal and bone safety associated with TDF use in the context of an aging CHB population. We will review data from phase 3 registration trials, which demonstrated TAF was not inferior to TDF in antiviral efficacy for both HBeAg-positive and HBeAg-negative patients, while associated with less reduction in the estimated glomerular filtration rate and bone mineral density. Expert commentary: Current data supports the use of TAF as one of the first-line antiviral agents for general CHB patients without hepatic decompensation. However, more real-world data with long-term observation are needed to better define the role of TAF among other oral regimens. Additional studies are also needed to evaluate the efficacy and safety of TAF in special populations such as those with impaired hepatic function, existing impaired renal and/or bone function, and in pregnant women.

    View details for PubMedID 28965428