Cynthia W. Ko
Adjunct Associate Professor
Health Sciences
Associate Chair for Faculty Affairs
Division of Gastroenterology

Faculty Information


Cynthia Ko, M.D., M.S., is a board certified gastroenterologist at the Digestive Health Center at UW Medical Center and a UW associate professor of Gastroenterology and Medicine and adjunct associate professor of Health Services.

Dr. Ko is a general gastroenterologist with interests in cancer screening and prevention, providing high quality care for patients with digestive health concerns and gastrointestinal endoscopy. She enjoys working with patients who are interested and actively engaged in their care. She likes to find options for patients to identify causes of their problems and understand their symptoms. It is important to her to help patients find ways to manage their own health.

Dr. Ko earned her M.D. at Stanford. Her clinical and research interests include general gastroenterology, endoscopy, colorectal cancer screening, quality of care and biliary tract disorders.

Board Certifications:

  • Gastroenterology, 1997, American Board of Internal Medicine
Education & Training: 
University of Washington - Robert Wood Johnson Scholars
University of Washington Affiliated Hospitals
Fellowship in Gastroenterology
University of Washington
Residency in Internal Medicine
Stanford University Medical Center
Internship in Internal Medicine
Stanford University Medical Center
Medical Education
Stanford University Medical Center
Research & Clinical Interests
Clinical Interests: 
  • Gastroenterology (Digestive)
  • Telehealth Services

Oksenberg JR, Judd AK, Ko C, Lim M, Fernandez R, Schoolnik GK, Steinman L. MHC-restricted recognition of immunogenic T cell epitopes of pertussis toxin reveals determinants in man distinct from the ADP-ribosylase site. J Exp Med 1988; 168:1855-1864. [original work]

Welch HM, Darby JK, Pilz AJ, Ko CW, Carritt B. Transposition, amplification, and divergence in the origin of the DNF15 loci, a polymorphic repetitive sequence family on chromosomes 1 and 3. Genomics 1989; 5:423-430. [original work]

Oksenberg JR, Ko C, Judd AK, Lim M, Kent A, Schoolnik GK, Steinman L. Multiple T and B cell epitopes in the S1 subunit ("A monomer") of the pertussis toxin molecule. J Immunol 1989; 143:4227-4231. [original work]

Ko CW, Murakami C, Sekijima JH, Kim MH, McDonald GB, Lee SP. Chemical composition of gallbladder sludge in patients after marrow transplantation. Am J Gastroenterol 1996; 91:1207-1210. [original work]

Ko CW, Gooley T, Shoch HG, Myerson D, Hackman RC, Shulman HM, Sale GE, Lee SP, McDonald GB. Acute pancreatitis in marrow transplant patients: prevalence at autopsy and risk factor analysis. Bone Marrow Transplant 1997; 20:1081-1086. [original work]
Ko CW, Kowdley KV, Haigh WG, Lee SP. Biliary lipid composition after liver transplantation: effect of allograft function and cyclosporine. Liver Transplant Surg 1998; 4:258-264. [original work]
Ko CW, Sekijima JH, Lee SP. Biliary sludge. Ann Intern Med 1999; 130:301-311. [review]
Ko CW, Lee SP. Gallstone formation: local factors. Gastroenterol Clin North Am 1999; 28:99-116. [invited review]
Ko CW, Beresford SAA, Jarvik GP, Schulte SJ, Calhoun B, Tsuchida AM, Lee SP. Apolipoprotein E and the risk of gallbladder disease in pregnancy. Hepatology 2000: 31:18-23. [original work]
Lee SP, Ko CW. Gallbladder disease. Clin Perspect Gastroenterol 2000; 3:87-96. [review]
Lee SP, Ko CW. Gallstones. Current Opinion Gastroenterol 2001. 17:463-467. [invited review]
Schwartz JM, Wolford JL, Thornquist MD, Hockenbery DM, Murakami CS, Drennan F, Hinds M, Strasser SI, Lopez-Cubero SO, Brar HS, Ko CW, Saunders MD, Okolo CN, McDonald GB. Severe gastrointestinal bleeding after hematopoietic cell transplantation, 1987-1997: incidence, causes, and outcome Am J Gastroenterol 2001; 96:385-393. [original work]
Ko CW, Kelley K, Meyer K. Physician specialty and outcomes of hospitalization for end-stage liver disease. Am J Gastroenterol 2001; 96:3411-3418. [original work]
Ko CW, Kreuter W, Baldwin LM. Effect of Medicare coverage on utilization of colorectal cancer screening tests. Arch Intern Med 2002; 162:2581-6. [original work]
Ko CW, Lee SP. Epidemiology and natural history of common bile duct stones and prediction of disease. Gastrointest Endosc 2002: 56:S165-9. [invited review]
Dominitz JA, Ko CW. To screen or not to screen for hepatocellular carcinoma, that is the question. Evidence-based Gastroenterology 2003; 4:57-58. [invited review]
Lee SD, Turgeon DK, Ko CW, Fritsche TR, Surawicz CM. Clinical correlation of toxin and common antigen enzyme immunoassay testing in patients with Clostridium difficile disease. Am J Gastroenterol; 2003; 98:1569-1572. [original work]
Nicolaidis C, Ko CW, Saha S, Koepsell TD. Racial discrepancies in the association between paternal vs. maternal educational level and risk of low birthweight in Washington State. BMC Pregnancy and Childbirth 2004; 4:10 (17 Jun 2004). [original work]
*Ko CW, Beresford SAA, Schulte SJ, Matsumoto AM, Lee SP. Incidence, natural history, and risk factors for gallbladder sludge and stones in pregnancy. Hepatology 2005; 41:359-365. [original work]
Ko CW, Kreuter W, Baldwin LM. Persistent demographic differences in colorectal cancer screening test utilization despite Medicare reimbursement. BMC Gastroenterology 2005; 5:10. [original work]
Ko CW, Schulte SJ, Lee, SP. Biliary sludge is formed by modification of hepatic bile by the gallbladder mucosa. Clin Gastroenterol Hepatol 2005. 3:672-678. [original work]
Ko CW, Sonnenberg A. Comparing risks and benefits of colorectal cancer screening in elderly patients. Gastroenterology 2005; 129:1163-1170. [original work]
Alexander J, Limaye AP, KoCW, BronnerMP, KowdleyKV. Association of hepatic iron overload with invasive fungal infection in liver transplant recipients. Liver Transplantation 2006; 12:1799-804. [original work]
Ko CW. Risk factors for gallstone-related hospitalization during pregnancy and the postpartum. Am J Gastroenterol 2006; 101:2263-8. [original work]
Ko CW. Biliary sludge and acute pancreatitis in pregnancy. Nature Clinical Practice Gastroenterology and Hepatology 2006; 3: 53-57. [invited review]
Ko CW, Riffle S, Shapiro JA, Saunders MD, Lee SD, Tung BY, Kuver R, Larson AM, Kowdley KV, Kimmey MB. Incidence of minor complications and time lost from normal activities after screening and surveillance colonoscopy. Gastrointest Endosc 2007; 65:648-56. [original work]
Etzel JD, Ko CW, Lee SD, Saunders MD, Kimmey MB, Tung BT, Eng S, Kowdley KV. Complications After Endoscopic Retrograde Cholangiopancreatography in Patients with Primary Sclerosing Cholangitis. Gastrointest Endosc 2008: 67:643-8. [original work]
Ko CW, Siddaiah N, Berger J, Gish R, Brandhagen D, Sterling RK, Sotler SJ, Fontana RJ, McCashland TM, Han SHB, Gordon FD, Schilsky ML, Kowdley KV. Prevalence of Hepatic Iron Overload and Association with Hepatocellular Cancer in End-Stage Liver Disease: Results from the National Hemochromatosis Transplant Registry. Liver International 2007; 27:1394-1401. [original work]
Ko CW, Beresford SAA, Schulte SJ, Lee SP. Insulin resistance and the incidence of gallbladder disease in pregnancy. Clin Gastroenterol Hepatol 2008;6:76-81. [original work]
Larson MF, Ko CW, Dominitz JA. Effectiveness of a provider reminder on fecal occult blood test follow-up. Dig Dis Sci 2009; 54:1991-6. [original work]
*Ko CW, Riffle S, Michaels L, Morris C, Holub J, Shapiro JA, Ciol MA, Kimmey MB, Seeff LC, Lieberman D. Serious complications within 30 days of screening and surveillance colonoscopy are uncommon. Clinical Gastroenterol Hepatol 2010; 8:166-73. [original work]
Ko CW, Dominitz JA, Green P, Kreuter W, Baldwin LM. Specialty differences in polyp detection, polyp removal, and biopsy at colonoscopy. Am J Med 2010; 123:528-35. [original work]
Ko CW, Dominitz JA, Green P, Kreuter W, Baldwin LM. Use and predictors of early repeat colonoscopy in Medicare beneficiaries. Am J Gastroenterol 2010; 2670-9. [original work]
Green BG, Wang CY, Horner K, Catz S, Meenan RT, Vernon SW, Carrell D, Chubak J, Ko CW, Laing S, Bogart A. Systems of support to increase colorectal cancer screening and follow-up rates (SOS): Design, challenges, and baseline characteristics of trial participants. Contemp Clin Trials 2010; 31:589-603. [original work]
Julka K, Ko CW. Infectious Diseases and the Gallbladder. Infect Dis Clin North Am 2010; 24:885-898. [invited review]
Dominitz JA, Ko CW. Colonoscopy Complications: Magnitude and Management. Gastrointest Endosc Clin North Am 2010; 20:659-71. [invited review]
Ko CW, Dominitz JA, Green P, Kreuter W, Baldwin LM. Accuracy of Medicare claims for diagnoses and findings during colonoscopy. Gastrointest Endosc. 2011; 73:447-53. [original work]
Naumann CR, Zelig C, Napolitano P, Ko CW. Upper gastrointestinal symptoms during pregnancy: a prospective evaluation of risk factors, treatment and outcome. J Matern Fetal Neonat Med 2012; 25:1488-93. [original work]
Green BB, Bogart A, Chubak J, Vernon SW, Morales LS, Meenan RT, Laing SS, Fuller S, Ko C, Wang CY. Non-participation in a population-based trial to increase colorectal cancer screening. Am J Prev Med 2012; 42:390-7. [original work]
Zisman TL, Bronner MP, Rulyak S, Kowdley KV, Saunders M, Lee SD, Ko CW, Kimmey MB, Stevens A, Maurer J, Brentnall TA. Prospective study of the progression of low-grade dysplasia in ulcerative colitis using current cancer surveillance guidelines. Inflamm Bowel Dis 2012; 18:2240-6. [original work]
Ko CW. Role of capsule endoscopy as a screening tool for colorectal cancer. Colorect Cancer 2012; 1:321-8. [invited review]
*Dominitz JA, Baldwin LM, Green P, Kreuter W, Ko CW. Regional variation in anesthesia assistance during outpatient colonoscopy is not associated with differences in polyp detection or complication rates. Gastroenterology 2013; 133:298-306. [original work]
Wong AC, Ko CW. Carbohydrate Intake as a Risk Factor for Biliary Sludge and Stones during Pregnancy. J Clin Gastroenterol 2013; 47:700-705. [original work]
Ko CW, Napolitano PG, Lee SP, Schulte SD, Ciol MA, Beresford SAA. Physical activity, maternal metabolic measures, and the incidence of gallbladder sludge or stones during pregnancy: a randomized trial. Am J Perinatol 2014; 31:39-48. [original work]
*Ko CW, Dominitz JA, Neradilek M, Polissar N, Green P, Kreuter W, Baldwin LM. Determination of colonoscopy indication from administrative claims data. Med Care. 2014;52(4):e21-9. [original work]
Mathew LK, Ko CW. Dietary protein and fat are not associated with gallstone incidence in pregnancy. J Parenter Enter Nutr 2015. 39(1):124-8. [original work]
Wheat CL, Clark-Snustad K, Devine B, Grembowski D, Thornton TA, Ko CW. Worldwide incidence of Colorectal Cancer, leukemia, and lymphoma in IBD: An updated systematic review and meta-analysis. Gastroenterol Res Pract 2016; 2016:1632439. [original work]
Wheat CL, Maass M, Devine B, Thornton TY, Grembowski D, Ko CW. Educational needs of patients with inflammatory bowel disease (IBD) and non-adherence to medical therapy- A qualitative study. J Inflam Bowel Dis & Disord 2016; 1:106 . [original work]
Lammert F, Gurusamy K, Ko CW, Miquel JF, Méndez-Sánchez N, Portincasa P, van Erpecum KJ, van Laarhoven CJ, Wang DQ. Gallstones. Nat Rev Dis Primers. 2016 Apr 28;2:16024. [invited review]
Tiderington E, Lee SP, Ko CW. Gallstones: new insights into an old story. F1000 Res 2016; 5. pii: F1000 Faculty Rev-1817. [invited review]
Liang PS, Mayer JD, Wakefield J, Ko CW. Temporal trends in geographic and sociodemographic disparities in colorectal cancer among Medicare patients, 1973-2010. J Rural Health 2017; 33:361-70. [original work]
Wheat CL, Clark-Snustad K, Ko CW, Grembowski D, Thornton T, Devine B. Inflammatory Bowel Disease (IBD) Pharmacotherapy and the Risk of Infection: A Systematic Review and Network Meta-Analysis. BMC Gastroenterology 2017 Apr 14; 17:52. [original work]
Heitkemper MM, Kain KC, Shulman RJ, Burr RL, Ko C, Hollister EB, Callen N, Zia J, Han CJ, Jarrett ME. Stool and urine trefoil factor 3 levels: associations with symptoms, intestinal permeability, and microbial diversity in irritable bowel syndrome. Benef Microbes 2018; 9:345-55. [original work]
Hollister EB, Cain KC, Shulman RJ, Jarrett ME, Burr RL, Ko C, Zia J, Han CJ, Heitkemper MM. Relationships of microbiome markers with extraintestinal, psychological distress, and gastrointestinal symptoms, and quality of life in women with irritable bowel syndrome. J Clin Gastroenterol 2018; doi 10.1097/MCG.0000000000001107. in press. [original work]
Ko CW, Singh S, Feuerstein JD Falck-Ytter C, Falck-Ytter Y, Cross RK, American Gastroenterological Association Institute Clinical Guidelines Committee. American Gastroenterological Association Institute Guideline on the management of mild-moderate ulcerative colitis. Gastroenterology 2019; 156:748-64. [clinical practice guideline]
Ko CW, Doria-Rose VP, Kamineni A, Barrett M, Weiss NS. Screening flexible sigmoidoscopy vs colonoscopy for reduction of colorectal cancer mortality. Int J Colorectal Dis 2019; 34:7123-81. [original work]
Oung B, Chea K, Oung C, Suarin JC, Ko CW. Endoscopic yield of chronic dyspepsia in outpatients: a single-center experience in Cambodia. J Gastroenterol Hepatol Open 2019. doi: 10.1002/jgh3.12210. in press [original work]
*Ko CW, Doria-Rose VP, Kamineni A, Barrett M, Weiss NS. Screening colonoscopy vs flexible sigmoidoscopy for reduction of colorectal cancer incidence. PLoS One 2019, 14(12): e0226027 [original work]
Liang PS, Mayer J, Wakefield J, Sherman S, Kwon S, Chau T, Ko CW. Trends in Sociodemographic Disparities in Colorectal Cancer Staging and Survival: a SEER-Medicare Analysis. Clin Transl Gastroenterol 2020. 11:e00155 [original work]
Issaka RB, Li L, Fedorenko C, Ko CW, Inadomi JM, Ramsey S. Racial disparities in colorectal cancer mortality: the role of endoscopy wait-time and stage at diagnosis. J Rural Ethnic Health Disparities 2020. 7L967074. [original work]
Austin E, Lee J, Bergstedt B, Mitchell AI, Javid S, Ko C, Gore J. “Help me figure this out”: qualitative explorations of patient experiences with cancer pathology reports. Patient Educ Couns 2020; 28:S0738-3991(30)30393-1. [original work]
Su GL, Ko CW, Bercik P, Falck-Ytter Y, Sultan S, Weizman A, Morgan R. American Gastroenterological Association Institute guidelines on the role of probiotics in the management of gastrointestinal diseases. Gastroenterology 2020. 159:697-705. [guideline]
Ko CW, Siddique S, Patel A, Harris A, Sultan S, Altayar O, Falck-Ytter Y. American Gastroenterological Association Institute guideline on the gastrointestinal evaluation of iron deficiency anemia. Gastroenterology 2020. 159:1085-94. [guideline]