Authors: Jiang, Donald¹; Renquist, Kathleen²; Mason, Edward²

Source: Obesity Surgery, Volume 1, Number 4, December 1991 , pp. 373-380(8)

Publisher: Springer

Abstract:

The purpose of this study was to develop a mathematical model to describe weight loss trend over time and to determine differences, if any, among various weight loss trends. Weight change was studied following Roux-en-Y gastric bypass (RGB) and vertical banded gastroplasty (VBG). The total number of patients analysed was 3172, 63.5% VBG and 36.5% RGB. Median age (years) for VBG was 36 (range 18-70) and RGB 38 (range 18-66). Median operative body mass index (BMI) (kg/m²) for VBG was 45.0 (range 30.1-90.5) and RGB 43.3 (range 30.4-80.6). Females represented 87% of the VBG patients and 89% of RGB patients. Obesity category percentages for each operative type were: super--VBG 20%, RGB 14%; morbid--VBG 78%, RGB 80%; obese--VBG 2%, RGB 6%. The development of a mathematical model to study weight loss over time was a two-stage process. First, weight loss trend was determined as evidenced by individual patient BMI values plotted over time. It was observed that plots represented quadratic curves, so the model BMI = B₀ + B₁(time) + B₂(time)² was used. Second, the estimated beta's (B₀, B₁, B₂) were treated as response variables to estimate weight loss trend for the combination effect of three independent variables: gender (male and female), obesity category (super, morbid, obese) and operative type (VBG and RGB). It was found that the three independent variables simultaneously interact with patient weight loss (p = 0.0001).

Keywords: Body mass index; obesity surgery; weight loss

Document Type: Research article

DOI: http://dx.doi.org/10.1381/096089291765560755

Affiliations: 1: Departments of Surgery and Preventive Medicine, The University of Iowa College of Medicine, Iowa City, USA 2: National Bariatric Surgery Registry, The University of Iowa College of Medicine, Iowa City, USA

Publication date: 1991-12-01

More about this publication?

• Information for Authors
• Terms & Conditions
• Ordering Journal Subscriptions
• ingentaconnect is not responsible for the content or availability of external websites

Related content

• In this: publication
• By this: publisher
• In this Subject: Surgery
• By this author: Jiang, Donald ;  Renquist, Kathleen ;  Mason, Edward

Website © Publishing Technology. Article copyright remains with the publisher, society or author(s) as specified within the article.

• Terms and conditions
• Privacy policy
• Information for advertisers