What Influences Bariatric Surgery Outcomes? – A Multiple Regression Analysis of the Ontario Bariatric Registry. 

Uri Kaplan, MD, Wael Zohdy, MD, MSc, Scott Gmora, MD, Dennis Hong, MD, MSc, Mehran Anvari, MD, PhD. McMaster University

Background: A number of factors have been proposed to impact the outcome of bariatric surgery. The aim of this study was to evaluate the relative influence of various factors which may impact patient selection and preparation. 

Methods: The Ontario Bariatric registry is a prospective data base of all patient undergoing bariatric surgery in 9 centers of excellence in Ontario. We analyzed the data on all  patients who underwent Laparoscopic Gastric Bypass (LRYGB) or Laparoscopic Sleeve Gastrectomy (LSG) between January 2010 and May 2013. Two early outcomes (90 days) were analyzed : 1.Composite adverse events ( Any of the following: Death, DVT, Stroke, Failure to discharge, reintervention, anastomotic leak and Cardiopulmonary complication), 2. Readmission. In addition, three late outcomes at one year were analyzed: 1.  Percentage of excess body weight loss (%EBWL), 2. Remission of Diabetes Mellitus (DM), 3. Remission of Hypertension. A multiple regression analysis was perform in order to identify independent variables that influence these early and late outcomes.

Results: 3166 patients  underwent LRYGB or LSG between January 2010 to May 2013 and completed their follow-up (mean age was 45 years (range 19-72); 83.8% women; mean body-mass index(BMI) [the weight in kilograms divided by the square of the height in meters] was 48.45). 89.7% underwent LRYGB. In 1.7% of the patients the composite adverse event outcome was positive.  preoperative ASA score was the only independent variable that influenced the composite adverse event outcome and obstructive sleep apnea (OSA) was the only one that influenced early readmissions. The independent factors that influenced %EBWL were age, type of surgery( LRYGB being better than LSG), initial BMI, initial HbA1c and albumin. Age was found to influence the remission of hypertension, and the level of initial HbA1c and the presence of OSA  were found to be the independent factors that influence the remission of DM.

Conclusion: The incidence of complications after bariatric surgery is low and can be predicted by the patient’s ASA score. The patient age seems less significant in the risk assessment and should not be used to exclude patients who may still experience significant benefit from bariatric surgery.

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