About

Hazem Shamseddeen, M.D., F.A.C.S., F.A.S.M.B.S., is a faculty member at the UC Davis Department of Surgery. His professional profile indicates his involvement in surgical practice and research within the department, which encompasses a broad range of surgical specialties including general, endocrine, and metabolic surgery. His role contributes to the department's mission of providing comprehensive surgical care, education, and research. While the provided page text lists his name among the faculty members and highlights the department's extensive clinical and research activities, it does not include specific details about his research focus, background, or key contributions. Therefore, the biography is limited to his professional affiliation and titles as listed.

Research topics

• Surgery
• Medicine
• General surgery
• Internal medicine

Selected publications

• Outcomes of hiatal hernia repair after Roux-en-Y gastric bypass: largest retrospective cohort study to date

  Surgery for Obesity and Related Diseases · 2025-06-18 · 1 citations

  articleOpen access
  PublisherOA PDFDOI

• Hyperkinetic Biliary Dyskinesia: An Underrecognized Problem With Good Surgical Outcomes After Cholecystectomy

  Cureus · 2024-06-26 · 4 citations

  articleOpen access

  Introduction While surgical indications for symptomatic cholelithiasis and biliary hypokinesia are clear, hyperkinetic biliary dyskinesia (HBD) is an underrecognized condition with poorly defined symptomology and management guidelines. HBD is typically defined as a gallbladder ejection fraction (EF) ≥ 80% on a hepatobiliary iminodiacetic acid (HIDA) scan. We aimed to identify the prevalence and radiographic reporting of HBD, physician referral patterns, and clinical outcomes following cholecystectomy. Methods A retrospective cohort study of patients with HIDA scans completed over 21 years at our tertiary care hospital was performed. Demographics, symptomatology, referral patterns, and operative data were collected. HBD was defined as HIDA EF ≥80%. Patients with HBD who underwent cholecystectomy were analyzed. ANOVA and chi-square tests were used to compare variables among patients with or without symptom improvement using Statistical Product and Service Solutions (SPSS; IBM SPSS Statistics for Windows, Armonk, NY). Results Of 1,997 patients (73% female, mean age 51.7 years) who had HIDA scans with reported EF, 730 (36.6%) had an EF≥80%. Only 13.7% of HIDA scans with EF≥80% were reported as hyperkinetic, and the rest are “normal”. Cholecystectomy was performed in 57 (7.8%) patients with EF≥80%, most being elective (89.5%) and all minimally invasive. Primary care physicians (PCPs) referred most elective cases to surgery (61.4%). The median time from HIDA to cholecystectomy was 146 days. Chronic cholecystitis was common in pathology (82.5%), while 38.6% had cholelithiasis. Overall, 53 patients (93.0%) reported symptom improvement at a median follow-up of 17.0 days. Patients without improvement had a higher prevalence of chronic gastrointestinal conditions (p<0.05), but not significantly more cholelithiasis, cholecystitis, time to surgery, or elective surgery status. Conclusions HBD is common but often underdiagnosed and thus likely underrecognized by treating physicians. Most HBD patients benefit from cholecystectomy, regardless of cholelithiasis. Patients with persistent symptoms after cholecystectomy may have confounding gastrointestinal diagnoses. Increased awareness among radiologists, referring PCPs, gastroenterologists, and surgeons about HBD and postoperative outcomes is needed to ensure that HBD is adequately treated.

  PublisherOA PDFDOI

• Metabolic disease remission after Roux-en-Y gastric bypass depends on preoperative disease severity: use of a new objective metabolic scoring system

  Surgery for Obesity and Related Diseases · 2024-08-17 · 1 citations

  articleOpen access
  PublisherOA PDFDOI

• Assessment of Obesity-related Metabolic Conditions: a novel objective scoring system better informs metabolic disease severity

  Surgery for Obesity and Related Diseases · 2024-09-19 · 3 citations

  articleOpen access
  PublisherOA PDFDOI

• S230 Risk Factors for Fecal Microbiota Transplant Failure and Their Utility in Predicting FMT Outcomes: A Nationwide Retrospective Study

  The American Journal of Gastroenterology · 2023-10-01

  article

  Introduction: Clostridioides difficile is one of the most common causes of healthcare-associated infection, often complicated by recurrent or severe C. difficile infections (CDI). Fecal microbiota transplant (FMT) is a well-established and effective treatment for recalcitrant CDI. However, not all patients successfully resolve CDI after FMT – a challenging clinical outcome. As CDI rates continue to rise, we investigated risk factors and predictors of FMT failure. Methods: This retrospective cohort study used the 2012-2020 MarketScan database. Using billing codes, we included adults with CDI who underwent an FMT. FMT failure was defined as recurrent CDI requiring antibiotics within 6 months after FMT. Patient demographics and multiple variables including inflammatory bowel disease (IBD) were compared (Table 1). A multivariable logistic regression (MLR) model was performed to assess the relationship between our covariates and FMT outcome. We included variables in the MLR model if they were statistically significant at the univariate level. A forward selection method was conducted, which took into consideration adjusted R2, AIC, and the log-likelihood to determine the best model fit. Statistical significance was defined as a P< 0.05. Results: Our FMT cohort included 1,126 adults (mean age of 58 years, 63% females), of which 207 (18.3%) had a failed FMT. Compared to FMT success, adults with FMT failure had higher odds of being older, females, with more comorbidities, and 4-fold higher odds of co-existing IBD (P< 0.0001). Outpatient vs inpatient FMT and FMT delivery method (colonoscopy vs other) were also associated with 4-fold and 8-fold higher odds of FMT failure, respectively (P< 0.0001). In contrast, a history of bariatric surgery was associated with 80% lower odds of FMT failure (P< 0.001). Immunosuppression, body mass index categories, pregnancy, malignancy, and prior CDI number were not associated with our FMT outcomes. In the final MLR model, age [odds ratio (OR) 1.022; 95%CI,1.01-1.03], male sex (OR 0.65; 95% CI, 0.45-0.94), IBD (OR 2.92; 95% CI, 2.01-4.2), and FMT delivery method (OR 3.03; 95%CI, 2.15-4.28) were predictive of future FMT outcomes. Other variables were not significant on the MLR. Figure 1 illustrates our MLR model's diagnostic ability. Conclusion: In this nationwide study, we suggest that age, sex, IBD, and FMT method can predict adults who will have an FMT failure. This data is critical for patient counseling, clinical decision-making, and future studies aimed at reducing CDI recurrence.Figure 1.: The Receiver Operator Characteristic (ROC) of the final MLR prediction model. Table 1. - Odds Ratio and Univariate Analysis Comparing FMT Failure vs FMT Success FMT Failure (n=207) FMT Success (n=919) P-Value Odd Ratio 95% CI Median or n IQR or % Median or n IQR or % Age (years) 64 50-78 58 47-67 < .0001 1.02 1.01 - 1.03 Sex < .0001 1.91 1.36 - 2.68 Male 53 26% 365 40% Female 154 74% 554 60% Charlson Comorbidity Score 3 1 - 4.0 2 1 - 3.0 < .0001 1.27 1.1 - 1.4 IBD 159 77% 396 43% < .0001 4.37 3.09 - 6.2 Immunosuppression 15 7% 53 6% 0.42 1.28 0.7 - 2.3 HIV 0 0% 2 0% 1 Immunosuppression medications 9 4% 30 3% 0.44 1.34 0.63 - 2.88 Transplant 7 3% 32 3% 0.94 0.97 0.42 - 2.23 BMI (kg/m2) 0.67 19-24 8 4% 26 3% 25-29 9 4% 36 4% 30-39 30 14% 148 16% 40 or greater 10 5% 59 6% Pregnant within 12 months Prior to FMT 1 0% 10 1% 0.7 0.44 0.05 - 3.47 Bariatric Surgery prior to FMT 4 2% 83 9% 0.0001 0.2 0.07 - 0.55 Active Malignancy 53 26% 296 32% 0.06 0.72 0.52 - 1.02 Abdominal Surgery prior to FMT 10 5% 101 11% 0.007 0.41 0.21 - 0.80 CDI Number prior to FMT 0.71 1.08 0.7 - 1.66 1 142 69% 229 25% >1 47 23% 70 8% FMT Delivery Method < .0001 4.4 3.2 - 6.1 Colonoscopy 138 67% 286 31% Other (e.g., oral or through enteroscopy) 69 33% 633 69% Hospitalization for FMT < .0001 8.18 5.73 - 11.7 Yes 47 23% 649 71% No 160 77% 270 29% Continuous variables represented as median/IQR and students Ttest utilized Chisq test / Fischers exact test used for categorical data

  PublisherDOI

• 2023 Scientific Session of the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES), Montréal, Canada, 19 March–April 1 2023: Video Loop

  Surgical Endoscopy · 2023 · 2 citations

  • Medicine
  • Surgery
  • General surgery
  DOI

• Psychological Predictors of Weight Loss Success Following Roux-en-Y Gastric Bypass

  Current Research in Diabetes & Obesity Journal · 2017-08-04

  articleOpen access1st authorCorresponding

  Current Research in Diabetes & Obesity Journal is an international peer reviewed Open Access journal of Juniper Publishers. CRDOJ is committed to increase knowledge, encouraging research and promoting better treatment for people suffering with Diabetes and Obesity.

  PublisherOA PDFDOI

• Changes in Renal Function Following Roux-en-Y Gastric Bypass: A Prospective Study

  Obesity Surgery · 2012-02-08 · 22 citations

  article
  PublisherDOI

• Epidemiology and Economic Impact of Obesity and Type 2 Diabetes

  Surgical Clinics of North America · 2011-10-03 · 120 citations

  review1st author
  PublisherDOI

• PL-114 Changes in renal function following Roux-en-Y gastric bypass: A prospective trial

  Surgery for Obesity and Related Diseases · 2011-05-01

  article
  PublisherDOI

Frequent coauthors

• Ashwin A. Kurian

  Colorado Kidney Care

  80 shared

• Fe ́lix Thibeault

  Hôpital du Sacré-Cœur de Montréal

  80 shared

• Christopher Le

  University of Colorado Denver

  64 shared

• Wai Ong

  Indiana University

  64 shared

• Zhen

  Stony Brook University Hospital

  64 shared

• Elana Davidson

  Holyoke Community College

  64 shared

• Michelle M. Dugan

  AdventHealth Tampa

  64 shared

• Tiffany Tan

  Liverpool Hospital

  64 shared

Labs

• Department of Surgery, UC Davis HealthPI

Awards & honors

• Felix D. Battistella M.D. Lectureship
• Charles F. Frey M.D. Lectureship
• James E. Goodnight Jr, M.D. Lectureship
• Donald P. Hause, M.D. Lectureship
• John M. Mott Jr, M.D. Lectureship