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External collaborators:

  • Dr. Gorden Jensen, University of Vermont
  • Dr. Glenn Gerhard, Temple University
  • Dr. Manish Parikh, NYU Bellevue
  • Dr. John Morton, Stanford
  • Dr. Jonathan Samuels, New York University
  • Dr. James Browne, University of Virginia
  • Dr. Clare Lee, John's Hopkins
  • Dr. Curt Dixon, Lock Haven University
  • Dr. Joe Andreacci, Bloomsburg University

Current studies


Obese patients pursing a TKA procedure are typically encouraged to lose weight prior to the procedure as part of the patient's treatment plan. If the patient chooses to receive treatment for his or her obesity, the Orthopedic provider may refer the patient to a weight management provider. If a patient is eligible for TKA and meets the inclusion and exclusion criteria (containing BMI and corresponding comorbidity measures), he/she is eligible to participate in the study.

In this study there will be two arms, a Test Arm in which patients undergo bariatric surgery prior to TKA and a Control Arm in which patients undergo TKA only. Patients will choose which arm they enter, based on whether or not they want to undergo surgical weight loss intervention prior to TKA.

The study hypothesis is that weight loss induced by bariatric surgery prior to TKA will improve TKA outcomes in patients with extreme obesity. The study hypothesis will be met if one of the following outcomes is achieved:

  1. In >=20% of bariatric surgery patients, the need for TKA was negated or delayed for at least two years.
  2. A statistically significant superiority is found among those patients undergoing bariatric surgery + TKA versus those undergoing TKA only in at least two of the following domains at two years post TKA:
  • Mobility (400 meter walk test)
  • Osteoarthritis outcome (WOMAC total score)
  • Knee orthopedic outcome (Knee Society score)
  • Quality of life (PROMIS-29 Quality of Life Questionnaire)
  • Osteoarthritic Pain (KOOS Pain)
  • Patient Satisfaction (If you had to live the rest of your life with the symptoms you have now, how would you feel?)

Bariatric Cardiovascular Pilot

Obesity is associated with an increased risk of cardiovascular disease related to direct pathophysiological effects on cardiac structure and function as well as pathophysiological effects on blood vessel function. Metabolic surgery has been shown to reverse these pathophysiological changes and induce cardiac remodeling, improve vascular reactivity, and reduced progression of atherosclerosis. The mechanisms underlying these favorable changes in cardiovascular function are largely unknown as is their time course and relationship to weight loss after metabolic surgery.

This study is designed to provide pilot information regarding the effects of bariatric surgery on cardiovascular function, the relationship of these changes to established biomarkers of cardiovascular disease, and the time course of these changes. Candidates for metabolic surgery with severe obesity will be selected in order to identify individuals with established cardiovascular disease related to obesity. Study candidates will undergo MRI imaging of the heart and blood vessels and biomarker analysis via blood draw and urine sample prior to undergoing metabolic surgery. Imaging and biomarker measurements will be repeated at eight weeks and six months after surgery.  

Findings from this study related to the time course of cardiovascular changes and their correlations with levels of circulating biomarkers will be used for pilot data supporting a publication and/or grant application.

PCORI Bariatric Study

The PCORI Bariatric Study is a comparative effectiveness research study to provide accurate estimates of the 1, 3, 5- year benefits and risks of the three main surgical treatment options for the severe obesity. The three main surgical treatments include roux-en-y gastric bypass (RYGB), adjustable gastric banding (AGB) and sleeve gastrectomy (SG). The study includes adults, children, and adolescents less than 80 years old at time of surgery who had one of the three most common procedures (RYGB, AGB, or SG) and all patients also have a Body Mass Index (BMI) measurement in the year prior to surgery that is at least 35 kg/m2.

The three factors that will be studied are:

  • to what extent weight is lost and regained
  • improvement in diabetes
  • risk of adverse events occurring in the three different surgical treatment options


There is a large unmet need in chronic liver disease research including NAFLD/NASH. This project is conducted in collaboration with Regeneron Pharmaceuticals. The goal of this research program is to understand the interplay between DNA sequence variation, gene expression and isoform use, and clinical phenotypes related to obesity and chronic liver disease by using:

  • transcriptomic profiling of liver and adipose tissue, coupled to array DNA genotyping and whole exome sequencing
  • clinical phenotypes captured in electronic health records (EHRs)
  • other data streams

In understanding putatively causal relationships among these molecular intermediates and clinical outcomes captured in EHRs, we hope to elucidate novel biology relevant to the identification of novel therapeutic targets for chronic liver diseases. The creation of a comprehensive, durable resource of deep functional genomics data, coupled to one of the most well-characterized populations with morbid obesity yet assembled, will empower additional investigations of the molecular basis of obesity-related phenotypes.

Bariatric Database and Biobank

Beginning in 2004, a prospective, robust bariatric registry has been supported by data from the electronic health record, patient reported results, and a vast biobank of patient samples including blood, serum, liver, adipose, stool, stomach, and jejunum. The registry is one of the largest and most expansive in the world, including data and samples from over 6,000 research consented patients with excellent long-term follow-up (80% at 4-years after surgery). This is recognized globally as a gold standard for bariatric research and has been used within >50 peer reviewed research publications.