PCORnet Bariatric Study
PCORnet Bariatric Study
The main goal of this research project is to conduct a comparative effectiveness research
 study involving existing data in the PCORnet Common Data Model to provide accurate estimates
 of the 1-, 3-, and 5-year benefits and risks of the three most common bariatric procedures -
 Roux-en-y gastric bypass, adjustable gastric banding, and sleeve gastrectomy - with a focus
 on outcomes that are important to adults and adolescents with severe obesity: 1) changes in
 weight, 2) rates of remission and relapse of diabetes, and 3) major adverse events.
The main aims of this study will compare the effectiveness and safety of the three most
 common bariatric surgical procedures: Roux-en-y gastric bypass (RYGB), adjustable gastric
 banding (AGB), and sleeve gastrectomy (SG).

 Question (Aim) 1: To what extent does weight loss and weight regain differ across the three
 bariatric surgical procedures at 1, 3, and 5 years? This aim addresses the primary outcome of
 interest among most patients seeking bariatric surgery - the differential impact of these
 procedures on maximum weight loss as well as the extent of longer-term weight regain. We will
 also explore the heterogeneity in weight loss and regain across several key subgroups that
 may have differential response to surgical treatment, specifically groups defined by age,
 race/ethnicity, baseline BMI, smoking status, and pre-operative comorbidities.

 Question (Aim) 2: To what extent do these bariatric procedures differ on improvements in
 diabetes risk at 1, 3, and 5 years? Among patients with diabetes, remission or "cure" of
 their disease (defined as HbA1c <6.5% off diabetes medications) has been cited as the most
 important outcome of bariatric surgery. Thus, we will examine the comparative effect of these
 procedures on rates of diabetes remission as well as relapse (recurrence). Secondary analyses
 will examine the comparative impact of the procedures on glycemic control independent of
 diabetes remission.

 Question (Aim) 3: What is the frequency of major adverse events following these three
 different bariatric surgical procedures at 1, 3, and 5 years? We will examine four important
 adverse event outcome categories across the three procedures: 1) short- and long-term (1, 3,
 and 5 year) mortality rates, 2) a composite end point of 30-day major adverse outcomes: based
 on the definition used in the Longitudinal Assessment of Bariatric Surgery (LABS) study that
 included death; venous thromboembolism; percutaneous, endoscopic, or operative subsequent
 intervention; and failure to be discharged from the hospital; 3) subsequent hospitalization
 (any hospitalization following initial surgery); and 4) subsequent
 reoperation/reintervention: defined as any additional bariatric procedure and other
 procedures related to device removals, gastric revisions, abdominal or incisional hernia
 repair, laparoscopy or laparotomy, and percutaneous endoscopic gastrostomy tube placements.
Inclusion Criteria:

 -  Adults and children age ≤79 years at time of surgery

 -  Had a primary (not revision) bariatric procedure from years 2005-2015 of one of three
 types:

 1. Roux-en-y gastric bypass (RYGB)

 2. Adjustable gastric banding (AGB)

 3. Sleeve gastrectomy (SG)

 We will use ICD-9-CM, CPT-4, and HCPCS codes to identify bariatric cases

 -  Have a Body Mass Index (BMI) measurement in the year prior to surgery that is ≥35
 kg/m2 for adults and adolescents.

 Exclusion Criteria:

 -  First bariatric procedure during the study period is a revision procedure, a vertical
 banded gastroplasty procedure (not used regularly since early 2000s) and the rarely
 used Biliopancreatic Diversion Procedure

 -  Have multiple bariatric procedures coded on the same day

 -  Have a ICD-9 diagnosis related to GI cancer occurring on day of surgery or during
 index hospitalization

 -  Emergency department visit on the same day as hospitalization for bariatric procedure