Analysis of weight loss after bariatric surgery using mixed-effects linear modeling.
Obes Surg
; 19(6): 732-7, 2009 Jun.
Article
en En
| MEDLINE
| ID: mdl-19277799
BACKGROUND: The standard analysis of bariatric surgery weight outcomes data (using t tests) is well known. However, these uncontrolled comparisons may yield misleading results and limit the range of research questions. The aim of the study was to develop a valid approach to the longitudinal analysis of weight loss outcomes after bariatric surgery using multivariable mixed models. This study has a multi-institutional setting. METHODS: We developed a mixed-effects model to examine weight after gastric bypass surgery while controlling for several independent variables: gender, anastomotic technique, age, race, initial weight, height, and institution. We contrasted this approach with traditional uncontrolled analyses using percent excess weight loss (%EWL). RESULTS: One thousand one hundred sixty-eight gastric bypass procedures were performed between 2000 and 2006. The average %EWL at 1, 2, and 3 years was 71%, 79%, and 76%, respectively. Using weight as the outcome variable, initial weight and gender were the only independent predictors of outcome (p<0.001). %EWL was substantially less accurate than weight as an outcome measure in multivariable modeling. Including initial weight and height as separate independent variables yielded a more accurate model than using initial body mass index. In a traditional uncontrolled analysis, average %EWL was higher in women than men. However, average weight loss was lower, not higher, in women (p<0.001) in our multivariable mixed model. Height, surgical technique, race and age did not independently predict weight loss. CONCLUSIONS: Multivariable mixed models provide more accurate analyses of weight loss surgery than traditional methods and should be used in studies that examine repeated measurements.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Derivación Gástrica
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Pérdida de Peso
Tipo de estudio:
Clinical_trials
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Etiology_studies
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Incidence_studies
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Observational_studies
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Prognostic_studies
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Risk_factors_studies
Límite:
Adult
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Aged
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Aged80
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Female
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Humans
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Male
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Middle aged
País/Región como asunto:
America do norte
Idioma:
En
Revista:
Obes Surg
Asunto de la revista:
METABOLISMO
Año:
2009
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos