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Center‐Size as a Predictor of Weight‐Loss Outcome in Multicenter Trials Including a Low‐Calorie Diet
Author(s) -
Gasteyger Christoph,
Christensen Robin,
Larsen Thomas M.,
Vercruysse Frank,
Toubro Soren,
Astrup Arne
Publication year - 2010
Publication title -
obesity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.438
H-Index - 199
eISSN - 1930-739X
pISSN - 1930-7381
DOI - 10.1038/oby.2010.118
Subject(s) - weight loss , medicine , trial registration , post hoc analysis , low calorie diet , single center , body weight , linear regression , demography , obesity , clinical trial , statistics , mathematics , sociology
It has not been studied yet whether factors such as the number of subjects recruited by specialized centers for multicenter trials may influence weight loss during a low‐calorie diet (LCD). This study aimed at determining whether the number of recruited subjects per center might predict relative weight loss. This is a post hoc analysis of an existing database: 701 obese subjects (77% women, 23% men, mean BMI: 38.9 kg/m 2 ) were enrolled at 22 sites (4–85 subjects/site) in five countries to follow a LCD providing 800–1,000 kcal/day during 8 weeks. The main outcome measure was the percentage weight loss after the 8‐week LCD. Mean weight loss differed significantly between participating centers (5.8–11.8% of the initial weight; P < 0.001). There was a significant positive correlation between relative weight loss and the number of recruited subjects per center ( r = 0.38; P < 0.001). In a multiple stepwise regression analysis, the number of recruited subjects per center appeared to be the main predictive factor of weight loss ( R 2 = 0.07; P < 0.001). As the number of participants within each center is clustered, we applied a hierarchical model to model the average weight loss vs. the number of participants included at each center. This model allows to predict that for 10 extra patients in a center, the average weight loss would increase by 0.5%. This is the first study suggesting that the number of recruited subjects per center may impact weight loss, and could therefore be considered as a new predictor for weight loss that is independent from the individual.