Adjunct Faculty
Adjunct faculty typically have an academic or research appointment at another institution and contribute or collaborate with one or more School of Medicine faculty members or programs.
Adjunct rank detailsCoskun Ozer Demirtas
Assistant Professor Adjunct of Medicine (Digestive Diseases)DownloadHi-Res Photo
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Assistant Professor Adjunct of Medicine (Digestive Diseases)
Biography
Dr. Coskun Ozer Demirtas is an Associate Professor of Medicine in the Division of Gastroenterology and Hepatology at Marmara University School of Medicine, Istanbul, Türkiye, and an Adjunct Assistant Professor of Medicine (Digestive Diseases) at Yale School of Medicine. He completed his medical education and fellowship training in Gastroenterology and Hepatology at Marmara University and has since been actively engaged in clinical and translational research in chronic liver diseases.
His research focuses on portal hypertension, hepatocellular carcinoma, and the development of noninvasive diagnostic and prognostic tools in hepatology. Dr. Demirtas has authored numerous peer-reviewed publications and has contributed to several international multicenter studies in liver disease and liver cancer.
Beyond his research activities, he holds leadership and educational roles within international hepatology organizations, including the American Association for the Study of Liver Diseases (AASLD), and is actively involved in initiatives advancing education, collaboration, and innovation in hepatology worldwide. His work seeks to bridge clinical practice and research to improve the care of patients with liver diseases.
Outside the clinic, he maintains an active interest in sports and enjoys traveling.
Last Updated on June 21, 2026.
Departments & Organizations
Research
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Overview
Dr. Demirtas's research focuses on portal hypertension, hepatocellular carcinoma, and chronic liver diseases, with an emphasis on developing noninvasive diagnostic and prognostic tools—including elastography-based approaches—to advance precision hepatology.
Medical Research Interests
Carcinoma, Hepatocellular; Hypertension, Portal; Liver Cirrhosis; Liver Diseases
Public Health Interests
Cancer
ORCID
0000-0002-0004-2740
Research at a Glance
Publications Timeline
A big-picture view of Coskun Ozer Demirtas's research output by year.
Research Interests
Research topics Coskun Ozer Demirtas is interested in exploring.
67Publications
742Citations
Carcinoma, Hepatocellular
Liver Cirrhosis
Liver Diseases
Publications
2026
Alcohol-associated Liver Disease in the MENA Region: A 16-Country Survey of Healthcare Provider Perspectives
El-Kassas M, Awad A, Medhat M, Yilmaz Y, Labidi A, AlNaamani K, Sanai F, Almattooq M, Debzi N, Tumi A, Benazzouz M, Yaghi C, Elbadry M, Alsenbesy M, Waked, Elzouki A, Nour M, Alswat K, Diaz L, Arab J, Younossi Z, Adali A, Abdulsalam A, FadlElmula A, Zafar A, Alsuleimani A, Saidani K, Khathlan A, Alghamdi A, Almaghrabi M, Numan M, Baseer M, Aldosari S, Alshumrani W, Alkalbani A, Al farsi B, Kamath B, Al Shuaili H, Alqartoobi H, Abumallouh I, Hamad K, Aladawi A, AlKaabi H, Omran H, Shajee M, Bichu R, Barakat A, Obaid J, Hamid A, Badi A, Rahil A, Muneerudeen A, Mathew J, Karayem M, Abulghasm T, Anwer Z, Alzanzagi A, Almalki F, Khan M, Alhouti A, Alansari B, Tawheed A, Gamie S, Abdelmoaty A, Abudeif A, Morsy K, Arafa U, Abdelhamed W, Sherief A, Abdelhalim A, Abdelmoez A, Zaky D, Sayed E, Abdella H, Hamed O, Ahmed Y, Abdelaziz A, Ramadan A, Elsharkawy A, Helmy A, Elmakhzangy H, Amin M, Elhaddad A, Al-Darmaki A, AlDhahab H, Al Mandhari M, AlHarthy N, Alsiyabi O, Gouda A, Algeblawi A, Ebrahim A, Hashmi A, Al balushi N, Al Jabri S, AlRiyami S, Alaamer A, Garrett B, Quintana D, Kantipudi M, Qoqazeh A, Albenmousa A, Caliskan A, Bozkina A, İldan A, Özkart B, Durmazer E, Turan I, Aslan İ, Afşin S, Kamalı S, Ali A, Uysal A, Candan S, Alghanem A, Khsiba A, Baki A, Chehaider A, Ayari M, Bellakhal S, Elfert A, Esmail E, Nasef M, Shehata M, Khalaf N, Elkafoury R, Gameaa R, Sainu A, Mohamed A, Sabbek A, Hammami A, Yakut A, Varlik B, Keklikkiran C, Ardıç C, Taşçı M, Başpınar B, Tofeeq B, Dertsiz B, Kanatsız E, Adalı G, Aykut H, Tuna M, saruhan M, Çavuş B, Chayma B, Burgucu B, Eren F, Keskin M, Özel M, Koca N, Ak Ç, Keçeci M, Berhili C, Chouqi N, ouardi W, Subasi C, Demirtas C, Tazegul G, Makni C, Alromaihi D, Mohamed D, Bardakji D, Swaiss M, Bajj N, Arı D, Cankurtaran R, Polat Y, Gökçe D, Khouildi D, Boughoula K, Parampil S, Al-hashmi S, Altan E, Binnetoglu E, Hassan E, Alhawaj F, Jamal H, Refay F, Jafarov F, Gul G, Gençdal G, Akyildiz M, Bilican G, Gökcan H, Yilmaz H, Endemic H, Khalifa R, Nagdy H, Jeddi H, Eruzun H, Kurtça İ, Odah H, Alqartoobi H, Bousorra H, Husen H, Nacef I, Kurt I, Ergenç I, Mostafa I, Al Qarshoubi I, Al Noumani J, Al-Naamani Z, İlter K, Hamad K, Matar K, Al Shaer M, Al-ShaikhAli M, Abdalaziz K, Farfar K, Mandoos K, Hassan M, Fissah M, Taharboucht S, Hashem M, Hassan M, Marwa Y, Biricik M, Yalniz M, Ozercan M, Çiçek S, Yıldız M, Kaban M, Yazidi M, Abdel-Samiee M, Hassan M, Ahmed M, Mohammed M, Ismail M, Durak M, Balaban Y, Eddine N, Zayyani N, Bellil N, Abdeen N, Belkahla N, Al-Salaita N, Sağlam O, Mejri O, Osmane R, Zmerli R, Elbadawy R, Mahdy R, Al Alawi S, Garad S, Awwad S, Altowairqi S, Cesur S, Acar S, Tosun Ş, Uyar S, Galal S, rhouma S, Alhejaili T, Kaoui T, Karahan T, AlAmeel T, Elagawy W, ouardi W, Gaba W, Hussein W, Almansoury Y, Mouldi Y, Bouteraa Y, Al Balushi Y, Zakri Y, Çetinkaya Ü. Alcohol-associated Liver Disease in the MENA Region: A 16-Country Survey of Healthcare Provider Perspectives. Annals Of Hepatology 2026, 102253. PMID: 42303045, DOI: 10.1016/j.aohep.2026.102253.Peer-Reviewed Original ResearchConceptsHealthcare providers' perceptionsAlcohol-associated liver diseaseHealthcare provider perspectiveCross-sectional surveyLow alcohol consumptionProviders' perceptionsProvider trainingProvider perspectiveSociocultural barriersClinical pathwayAlcohol consumptionLiver diseaseLiver disease managementDisease managementMENA countriesRoutine assessmentCulturally sensitive settingsClinical practiceDiagnosis patternsStigmaMedical managementProvidersClinical experienceRegion-specific guidelinesNutritional supportChronic kidney disease in cirrhosis: a study of inpatients from a global perspective.
Wong F, Adebayo D, George J, Idilman R, Hayes PC, Alvares-da-Silva MR, Torre A, Mekonnen HD, Seto WK, Sarin SK, Cao Z, Rajoriya N, Nagral A, Fisseha H, Kulkarni AV, Zhu C, Debzi N, Farias AQ, Su M, Goel A, Marciano S, Livingstone R, Dhiman RK, Gao Y, Malé-Velázquez R, Demitars CO, Bera C, Jiang YF, Velarde-Ruiz Velasco JA, Tan HK, Zhao C, Huezo MSG, Asrani SK, Wang L, Lu M, Michalczuk MT, Barutcu S, Cordova-Gallardo J, Gofton C, Gounder M, Shaw J, Albhaisi S, Zheng X, Aravinthan A, Rajaram RB, Jothimani D, Thanapirom K, Benitez C, Dincer D, Saraya A, Xu B, Lin M, Wu X, Liu C, Reddy R, Bush B, Thacker LR, Topazian M, Xie Q, Silvey S, Kamath PS, Choudhury A, Bajaj JS, CLEARED Investigators. Chronic kidney disease in cirrhosis: a study of inpatients from a global perspective. Gut 2026 PMID: 42248676, DOI: 10.1136/gutjnl-2025-336802.Peer-Reviewed Original ResearchMachine Learning Models Using Hospital Admission Characteristics Do Not Optimally Predict Nosocomial Infection Development in a Global Cirrhosis Cohort.
Silvey S, Choudhury A, Kamath P, Xie Q, Wong F, Hayes P, Seto W, Arora U, Singhal G, Jothimani D, Asrani S, Gadano A, Dincer D, Farias A, Adebayo D, Velarde-Ruiz Velasco J, Doyle A, Kulkarni A, Debzi N, Shaw J, Barutcu S, Desalgn H, Bettinger D, Regis Lah P, Duarte-Rojo A, Turan D, Wang L, Velazquez R, Zheng X, Aghayaeva S, Karasu Z, Demirtas C, Liu C, Cordova-Gallardo J, Xu B, Nagral A, Gao H, Elangovan H, Fung J, Rajorya N, Wang X, Katchmann H, Praharaj D, Mahadeva S, Jiang Y, Zheng K, Thanapirom K, Eapen C, Dhiman R, Lu M, Arrese M, Su M, Hueso S, Zhu C, Aberra H, Fisseha H, Tan H, Zhao C, Zhang N, Taneja S, Aravinthan A, Sonavane A, Saraya A, Gofton C, MacQuillan G, Pereira G, Reddy K, Sarin S, Cao Z, Topazian M, Idilman R, Torre A, George J, Alvares da Silva M, Bush B, Bajaj J. Machine Learning Models Using Hospital Admission Characteristics Do Not Optimally Predict Nosocomial Infection Development in a Global Cirrhosis Cohort. The American Journal Of Gastroenterology 2026 PMID: 42043180, DOI: 10.14309/ajg.0000000000004031.Peer-Reviewed Original ResearchAltmetricConceptsArea under the receiver operating characteristic curvePositive predictive valueNosocomial infectionsDay of admissionCirrhosis cohortNosocomial infection developmentAssociated with high mortalityUrinary tract infectionSpontaneous bacterial peritonitisHigh-risk patientsHospital admission characteristicsReceiver operating characteristic curveLogistic regressionSevere liver diseaseInfection control measuresOperating characteristics curveAssociated with inpatient mortalityBacterial peritonitisTract infectionsLiver transplantationAlcoholic etiologyClinical dataAdmission infectionsLiver diseaseHospitalized patientsGastrointestinal Bleeding as an Unusual Presentation of Groove Pancreatitis Complicated by Intramural Duodenal Hematoma
Tolu T, Kaldirim Armutcuoglu Y, Yilmaz Yildirim T, Yılmaz Duz M, Tiras H, Ozen Alahdab Y, Ozdogan O, Ozer Demirtas C. Gastrointestinal Bleeding as an Unusual Presentation of Groove Pancreatitis Complicated by Intramural Duodenal Hematoma. The Turkish Journal Of Gastroenterology 2026 PMID: 42027139, DOI: 10.5152/tjg.2026.26084.Commentaries, Editorials and LettersConceptsBioelectrical impedance-derived phase angle as a contextual indicator for steatotic liver disease and hepatic fat estimation
Sabuncular G, Çelik Z, Demirtaş C, Aktaç Ş, Eren F. Bioelectrical impedance-derived phase angle as a contextual indicator for steatotic liver disease and hepatic fat estimation. Frontiers In Nutrition 2026, 13: 1787419. PMID: 42039899, PMCID: PMC13105901, DOI: 10.3389/fnut.2026.1787419.Peer-Reviewed Original ResearchConceptsBioelectrical impedance analysisBody fat percentageMulti-frequency bioelectrical impedance analysisWhole-body phase angleCross-sectional studySteatotic liver diseaseMetabolic risk factorsBody mass indexContextual indicatorsModerate discriminative abilityMultivariate logistic regression analysisLogistic regression analysisWaist circumferenceImpedance analysisAnthropometric variablesLiver diseaseFat percentageNutritional assessmentMass indexObese subgroupBody compositionControlled attenuation parameterRisk factorsFat estimatesHepatic fat content
2025
Efficacy and tolerability of tenofovir alafenamide fumarate prophylaxis in HBV-infected individuals receiving chemo/immunosuppressive therapy
Dilber F, Durak S, Unsal Y, Demir M, Yildirim A, Ellik Z, Mehdiyev S, Adanir H, Yapali S, Demirtas C, Ucbilek E, Balaban Y, Ekmen N, Gokcan H, Koc E, Dincer D, Sezgin O, Simsek H, Tozun N, Arslan M, Idilman R, Etik D, Gokcen P, Ari D, Ozdil K, Akdogan M, Boyacioglu S. Efficacy and tolerability of tenofovir alafenamide fumarate prophylaxis in HBV-infected individuals receiving chemo/immunosuppressive therapy. Hepatology Forum 2025, 7: 26-31. PMID: 41589209, PMCID: PMC12831986, DOI: 10.14744/hf.2025.62002.Peer-Reviewed Original ResearchConceptsFollow-up periodHBV reactivationDrug discontinuation due to adverse effectsAbnormal serum alanine aminotransferase levelsHepatitis B virus (HBV)-infectionDiscontinuation due to adverse effectsEvidence of HBV reactivationMedian follow-up periodDetectable HBV DNA levelsSerum alanine aminotransferase levelsGlomerular filtration rate changesBiologic modifier therapySerological evidenceHBV DNA levelsHepatitis B surface antigenVirological response ratesAlanine aminotransferase levelsHBV-related morbiditySerum triglyceride levelsHBV-infected individualsB surface antigenPrimary disease typeFiltration rate changesCase report formsElectronic case report formsBALAD-2 Emerges as the Most Accurate Prognostic Model in Hepatocellular Carcinoma: Results from a Biobank-Based Cohort Study
Demirtas C, Eren F, Karadag D, Armutcuoglu Y, Tolu T, Huseyinov J, Ciftci U, Yilmaz T, Akin S, Dilber F, Ozdogan O. BALAD-2 Emerges as the Most Accurate Prognostic Model in Hepatocellular Carcinoma: Results from a Biobank-Based Cohort Study. Cancers 2025, 17: 3457. PMID: 41228250, PMCID: PMC12610203, DOI: 10.3390/cancers17213457.Peer-Reviewed Original ResearchCitationsConceptsArea under the receiver operating characteristic curveBALAD-2Hepatocellular carcinomaPrognostic performanceOverall survivalRisk stratificationSerum biomarkersEtiological subgroupsAccurate prognosticationPrognostication of hepatocellular carcinomaAssociated with OSClinical risk stratificationHepatocellular carcinoma managementHarrell's concordance indexReceiver operating characteristic curveLiver disease etiologyOperating characteristics curveNoncurative therapyAccurate prognostic modelCurative therapyHCC cohortViral etiologyPatient subgroupsC-indexConcordance indexHepatic steatosis is associated with HBsAg seroclearance in patients with chronic hepatitis B virus infection but it is also associated with disease progression.
Bodakci E, Kiremitci S, Ellik ZM, Koc O, Gumussoy M, Yilmaz V, Gokcan H, Erhan AH, Guvenir ST, Er RE, Savas B, Idilman R. Hepatic steatosis is associated with HBsAg seroclearance in patients with chronic hepatitis B virus infection but it is also associated with disease progression. Hepatol Forum 2025, 7: 14-20. PMID: 41589211, DOI: 10.14744/hf.2025.74529.Peer-Reviewed Original ResearchRare Presentation of Immunoglobulin G4–Related Disease: Hepatic Mass Lesions Mimicking Metastasis
Division of Gastroenterology and Hepatology M, Yıldırım T, Çiftçi U, Huseynov J, Demirtaş C, Özdoğan O. Rare Presentation of Immunoglobulin G4–Related Disease: Hepatic Mass Lesions Mimicking Metastasis. The Turkish Journal Of Gastroenterology 2025, 37: 273-275. PMID: 41669935, PMCID: PMC12910293, DOI: 10.5152/tjg.2025.25211.Peer-Reviewed Original ResearchCitationsEnhancing Hepatocellular Carcinoma Surveillance: Comparative Evaluation of AFP, AFP-L3, DCP and Composite Models in a Biobank-Based Case-Control Study
Demirtas C, Akin S, Karadag D, Yilmaz T, Ciftci U, Huseynov J, Bulte T, Kaldirim Y, Dilber F, Ozdogan O, Eren F. Enhancing Hepatocellular Carcinoma Surveillance: Comparative Evaluation of AFP, AFP-L3, DCP and Composite Models in a Biobank-Based Case-Control Study. Cancers 2025, 17: 2390. PMID: 40723271, PMCID: PMC12293724, DOI: 10.3390/cancers17142390.Peer-Reviewed Original ResearchCitationsConceptsOptimal cut-offCase-control studyHepatocellular carcinomaViral etiologyAlpha-fetoproteinNon-viral hepatocellular carcinomaDes-gamma-carboxy prothrombinEarly-stage hepatocellular carcinomaHCC surveillance strategiesCut-offAlpha-fetoprotein statusEarly-stageHepatocellular carcinoma surveillanceReceiver operating characteristic analysisOperating characteristic analysisEvaluation of AFPGALAD scoreAFP-L3GALADDiagnostic performanceSubgroup analysisCarcinomaBiomarker modelSurveillance strategiesIndividual biomarkers
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