Nowadays bariatric surgery has become the best treatment option for morbid obesity. RYGB is an effective and long-lasting treatment for weight loss and comorbidity improvement. Long-term data regarding gastric bypass have been lacking due to the complexity of issues regarding follow-up [4, 16-18]. There is no consensus in the literature indicating which factors can actually predict success after bariatric surgery, despite a similarity in the characteristics of the samples in terms of age, sex, preoperative BMI, T2DM, high blood pressure, and dyslipidemia . Therefore, more studies with long-term follow-up should be carried out to investigate the effect of these factors on weight loss.
In our study, a 5-years follow-up analysis was performed. Our data demonstrated that the mean age of all patients were 40.1 years with BMI of 45.78 kg/m² that 80% were female. There was no significant difference among age, BMI and sex between diabetic and non-diabetic patients at the surgery which shows the homogeneity of these variables. Also, marriage and educational level were not significantly different between diabetic and non-diabetic groups. The present study has strengths and limitations. The relatively high number of the patients enrolled in this study is strength, as well as a prolonged and excellent follow-up rate of 93% for 5 years.
The patients’ %EWL was 59% and 74% in 6 months and 12 months follow-up, respectively. Our findings regarding %EWL are similar to those of Sjöström L, who reported that most patients can expect to lose more than 50 % of their excess weight and an average excess weight loss of more than 70% can be expected in the first 12 months after the surgery .
In the study of Junior et al., a progressive loss of excess weight following RYGB was observed along the follow-up periods up to the second year (45%, 64%, 70%, and 73% excess weight loss at 6, 12, 18, and 24 months, respectively) . Our results demonstrated suitable weight loss in short and mid-term follow-up which has been achieved in many other studies. It can be concluded that RYGB induces excellent weight loss in morbidly obese patients.
The %EWL and %EBMIL changes showed that there was no significant difference between diabetic and non-diabetic groups until 9months follow-up, but after that %EWL and %EBMIL was significantly higher in non-diabetic group. In both groups, weight loss trajectory stopped after 18 months.
Sjöström L. also reported that weight loss with RYGB was maximal at 24 months . In our study T2DM lead to a lower weight loss in comparison to non-diabetic patients, which is in agreement with the literature. In a 4-year follow-up study, Junior et al. found that patients with T2DM had a lower weight loss at 18 months after RYGB versus non-diabetic ones . It may be related to insulin metabolism and patient compliance. Diabetic patients, due to hypoglycemia following drug consumption, eat more sweaty food which may lead to weight gain. On the other hand, interactive relation among glucose metabolism, appetite and body basal metabolism can affect weight changes.
The evaluations demonstrated a higher rate of %EBMIL in male patients in short-term follow-up, which was not different in long term. It may be related to psychological and physical characteristics of men. In contrast to our data analysis, Junior et al. in a 4-year follow-up revealed that male sex was associated with limited success after RYGB . This controversy has been concluded by other reports, as determining an effect of sex is complicated due to the fact that the majority of studies include samples that are made up mostly of women [21-23].
On the other hand, in short-term and long-term follow-up, super-obese patients (BMI>50 kg/m²) had a significantly lower %EWL in comparison with patients with BMI<50 kg/m². This association between higher baseline BMI and lower %EWL has been reported in the literature . This finding may be induced by the lower activity level of super-obese patients due to their higher weight and probable musculoskeletal problems. Also, it can be caused by inappropriate eating habits in comparison with patients with BMI<50.
The main objectives of bariatric surgery are to promote a significant and sustainable weight loss, to improve or resolve comorbidities, and to promote a better quality of life, with low rates of preoperative and long-term complications. However, weight loss is not homogeneous in this population, even with technical standardization of the surgery [19, 24].
The weakness point of this study is that it is retrospective and based on database information. Furthermore, all included patients had 150cm alimentary and 50cm biliary limb length; on the other hand, since weight changes are multifactorial, some variables such as calorie consumption, physical activity and eating habits were not evaluated. We recommend that these results should be investigated in long term follow-up.