OBJECTIVE: To analyze the changes in the body composition of morbidly obese patients induced by a very low-calorie diet. METHODS: We evaluated 120 patients selected from a university hospital. Body composition was assessed before and after the diet provided during hospitalization, and changes in weight, body mass index, and neck, waist and hip circumferences were analyzed. Bioimpedance was used to obtain body fat and fat-free mass values. The data were categorized by gender, age, body mass index and diabetes diagnosis. RESULTS: The patients consumed the diet for 8 days. They presented a 5% weight loss (without significant difference among groups), which represented an 85% reduction in body fat. All changes in body circumference were statistically significant. There was greater weight loss and a greater reduction of body fat in men, but the elderly showed a significantly higher percentage of weight loss and greater reductions in body fat and fat-free mass. Greater reductions in body fat and fat-free mass were also observed in superobese patients. The changes in the diabetic participants did not differ significantly from those of the non-diabetic participants. CONCLUSIONS: The use of a VLCD before bariatric surgery led to a loss of weight at the expense of body fat over a short period, with no significant differences in the alteration of body composition according to gender, age, body mass index and diabetes status.

Resumo Objetivo: examinar a perda de peso nos primeiros 18 meses em pacientes submetidos à cirurgia bariátrica. Métodos: um estudo de coorte retrospectiva foi realizado com 241 adultos submetidos à gastroplastia, entre janeiro/2006 e dezembro/2008, em um centro em São Paulo (Brasil). Foi feita a revisão dos prontuários e as variáveis analisadas foram sexo, idade, peso pré-cirúrgico imediato, adesão ao seguimento nutricional pós-operatório e duração do período pós-operatório. A proporção do peso inicial perdido durante os 18 primeiros meses pós-cirurgia foi analisada pela técnica de equações generalizadas de estimação. Resultados: 81% (n=195) eram mulheres; média de idade 44,4 ± 11,6 anos; média de peso pré-operatório 123,1± 21,2 kg; média do índice de massa corporal 47.2± 6.2 kg/m2. A prevalência de adesão ao seguimento nutricional pós-cirúrgico foi de 51% (IC95% = 44,5-57,5%). Peso pré-cirúrgico e adesão não se mostraram significativamente associados à redução da proporção do peso inicial (Teste de Wald p>0,18). A perda de peso tendeu a diminuir no final do período de 18 meses pós-cirúrgico nos grupos de pacientes aderentes e não aderentes (Teste de Wald p=0,00). Conclusão: nosso estudo mostrou que a perda de peso durante os primeiros 18 meses após a cirurgia chega a 40% do peso. O emagrecimento não foi associado ao peso pré-operatório, nem à adesão ao seguimento nutricional pós-cirúrgico e pode depender, principalmente, das alterações promovidas pelo procedimento cirúrgico em si. Esse achado poderá levar à proposição de intervenções para motivar os pacientes ao seguimento pós-operatório.

Summary Objective: to examine the association between preoperative body weight, adherence to postsurgical nutritional follow-up, length of postoperative period, and weight loss during the first 18 months among adults who have undergone bariatric surgery. Methods: a retrospective cohort study was conducted on 241 consecutive patients who underwent open Roux-en-Y gastric bypass (RYGBP) from January 2006 to December 2008, in a teaching hospital in São Paulo (Brazil). Data were collected through hospital records review and the variables analyzed included sex, age, immediate preoperative weight, adherence to postsurgical nutritional visits and length of postoperative period. Proportional body weight reductions during the 18-month follow-up period were examined using generalized estimating equations. Results: 81% (n=195) of participants were female, with overall mean age of 44.4 ± 11.6 years, mean preoperative weight of 123.1± 21.2 kg and mean preoperative body mass index of 47.2± 6.2 kg/m2. The overall adherence to postoperative follow- up schedule was 51% (95%CI: 44.5-57.5%). Preoperative body weight and adherence were not associated with proportional weight reduction (Wald’s test p > 0.18). Weight loss leveled off at the end of the 18-month follow-up period for both compliant and non-compliant patients (Wald’s test p = 0.00). Conclusions: our study showed that weight loss occurred steadily over the first 18 months after RYGBP, leveling off at around 40% weight reduction. It was associated with neither presurgical weight, nor nutritional follow-up and it may be primarily dependent on the surgical body alterations themselves. This finding may have implications for intervention strategies aimed at motivating patients to comply with early postsurgical and life-long follow-up.

OBJETIVO: Estimar a prevalência da adesão ao seguimento nutricional ambulatorial pós-cirúrgico e avaliar sua associação com fatores selecionados em indivíduos submetidos à cirurgia bariátrica. MÉTODOS: Estudo de coorte retrospectiva com base na revisão de dados pós-operatórios de 241 prontuários de adultos submetidos à gastroplastia redutora com derivação em Y de Roux entre 2006 e 2008. Considerou-se aderente o indivíduo que compareceu a quatro ou mais consultas nutricionais nos 12 primeiros meses após a cirurgia. Para investigar a associação entre adesão ao seguimento nutricional e idade, sexo, estado conjugal, escolaridade, situação empregatícia, distância entre a residência e o hospital, estratégias para perda de peso no período pré-operatório, índice de massa corporal no pré-cirúrgico imediato, presença de comorbidades e duração da internação pós-operatória, foram calculadas razões de prevalência e utilizou-se regressão múltipla de Poisson. RESULTADOS: A prevalência de adesão foi de 56% (IC95%=49,7-62,3) nessa população predominantemente feminina (80,9%), com média de idade de 44,4 anos (DP=11,6) e de IMC pré-operatório de 47,2kg/m² (DP=6,2). Dos fatores estudados, somente a duração da internação pós-operatória igual ou superior a 6 dias mostrou-se significativamente associada à adesão após análise ajustada por sexo e idade (RP=1,46; IC95%=1,15-1,86). CONCLUSÃO: A prevalência de adesão encontrada foi semelhante às de estudos internacionais, mas baixa considerando-se 75% como referência. A maior adesão observada nos indivíduos com internação pós-operatória prolongada pode sugerir que o maior contato com a equipe multiprofissional aumente a percepção da necessidade de cuidados com a saúde em longo prazo.

OBJECTIVE: This study estimated the prevalence of adherence to outpatient postoperative nutritional follow-up after bariatric surgery and analyzed the association between adherence and selected factors. METHODS: A total of 241 records of female and male adults who underwent Roux-en-Y gastric bypass between 2006 and 2008 were reviewed for this retrospective cohort study. The data included the preoperative and postoperative periods. Individuals were considered compliant when they attended four or more nutritional appointments in the first 12 months after surgery. Prevalence ratios were calculated for estimating the association between adherence to postoperative nutritional follow-up and factors such as age, gender, marital status, education level, employment status, distance between home and hospital, weight loss strategies used during the preoperative period, body mass index immediately before surgery, presence of comorbidities and duration of hospital stay after surgery, and the Poisson multiple regression was used for adjusted analysis. RESULTS: Adherence prevalence was 56.0% (CI95% 49.7-62.3). Women composed 80.9% of the population; the mean age of the sample was 44.4 years (SD=11.6) and mean preoperative body mass index was 47.2kg/m² (SD=6.2). Among the study factors, only duration of postoperative hospital stay was significantly associated with adherence after adjustment for age and gender (PR=1.46 CI95% 1.15-1.86). CONCLUSION: The adherence prevalence of this population was similar to those of foreign studies, but below the minimum prevalence of 75% considered reference. The greater adherence of individuals with longer postoperative hospital stays may have stemmed from their prolonged interaction with the multidisciplinary team, which may have increased their awareness of disease severity and need of long-term health care.