|Year : | Volume
| Issue : | Page :
Effect of pre-operative weight loss on patients' outcomes undergoing laparoscopic sleeve gastrectomy
Ozan Sen1, Ahmet Gökhan Türkçapar2
1 Türkçapar Bariatrics, Obesity Center; Department of Health Sciences, Nişantaşı University, Istanbul, Turkey
2 Türkçapar Bariatrics, Obesity Center, Istanbul, Turkey
|Date of Submission||21-Nov-2020|
|Date of Decision||18-Feb-2021|
|Date of Acceptance||12-Mar-2021|
|Date of Web Publication||01-May-2021|
Türkçapar Bariatrics, Obesity Center, Dikilitaş Mah. Ayazmadere Cad, Yeşil Çimen Sok No: 9, Beşiktaş 34394, Istanbul, Turkey; Maslak Mah, Söğütözü Sok, No. 20, Maslak 1453, Sarıyer 34398, Istanbul
Source of Support: None, Conflict of Interest: None
Background: The study aims to demonstrate whether weight loss with a low-calorie diet before laparoscopic sleeve gastrectomy (LSG) may affect the outcomes.
Materials and Methods: A total of 305 patients undergoing primary LSG were included in the study. Each patient adopted a low-calorie diet (1000 calories) before LSG. The patients were stratified into two groups. Group A: Those who lost 3% or more of their total body weight loss (TBWL), Group B: Those who lost <3% of their TBWL. Two groups were compared in terms of operative time, length of hospital stay, complications and weight loss outcomes.
Results: One hundred and five patients (35%) were in Group A and 200 patients were in Group B. Median weight loss was 4 kg (3–20 kg). Pre-operative mean body mass index (BMI) was 40 ± 7.4 kg/m2 in Group A and 41 ± 5.9 kg/m2 in Group B (P = 0.06). At 1 year after the surgery, BMI regressed to 29.7 ± 4.9 kg/m2 in Group A and to 27 ± 4.2 kg/m2 in Group B (P < 0.001). One hundred and twenty-nine patients who completed 2 years of follow-up, mean BMI regressed to 29.4 ± 4.1 kg/m2 in Group A (n = 46) and to 27.2 ± 4.5 kg/m2 in Group B (n = 83) (P < 0.001). In Group B, one patient experienced post-operative bleeding. No other complications were observed in the study. There was no significant difference between the groups in terms of operative time (P = 0.53) and length of hospital stay (P = 0.9).
Conclusion: Weight loss before LSG does not improve post-operative weight loss.
Keywords: Bariatric surgery, pre-operative diet, sleeve gastrectomy, weight loss success
| ¤ Introduction|| |
Obesity is a chronic disease, and currently, bariatric surgery is the most effective treatment to combat with it., Laparoscopic sleeve gastrectomy (LSG) as a surgical method has become the most commonly performed technique, particularly in recent years., A good pre-operative preparation before bariatric surgery may provide improved post-operative results., For this purpose, most centres give their patients a low-calorie diet for 2–3 weeks before surgery. This practice primarily aims to reduce liver steatosis., It is thought that this may allow better visibility and more convenience during the surgery as well as reducing intraoperative and post-operative complications. In addition, the pre-operative diet is expected to improve patient compliance and aid weight loss in the post-operative period. Whether the diet applied before bariatric surgery is effective in this regard remains controversial. Our study aims to demonstrate whether weight loss with a 2-weeks low-calorie diet before LSG may affect surgery outcomes.
| ¤ Materials and Methods|| |
This study was conducted at a private bariatric surgery centre and was approved by the Institutional Ethics Committee (ATADEK 2020-19/02). All patients were informed about the study in detail, and written consents were obtained. A total of 305 patients undergoing primary LSG between March 2018 and September 2020 who completed at least 1 year of follow-up were included in the study. Patients' data, which were recorded prospectively, were analysed retrospectively. Patients with body mass index (BMI) over 50 kg/m2, who underwent revision surgery and those undergoing additional surgical procedures in the same session, were excluded from the study. Our pre-operative workup protocol and surgical technique has been previously described.
All the patients were screened by detailed laboratory tests with respect to metabolic parameters (liver, kidney, thyroid function, lipid profile, fasting blood glucose, insulin level, Hba1c, C peptide and uric acid) and vitamin deficiency (ferritin, B 12, folic acid, Vitamin D). Oesophagogastroduodenoscopy and abdominal ultrasound were performed for each patient. Each patient was evaluated by a multidisciplinary team (dietitian, psychiatrist, cardiologist, pulmonologist, endocrinologist and anaesthetist.
Each patient adopted a low-calorie diet (1000 calories) for 2 weeks before the surgery. Patients were informed about the possible benefits expected from this diet.
All LSG operations were done by the same team and the same technique. Using an optical trocar for the first entry, with a five-trocar technique, and sleeve gastrectomy over a 36 French bougie, starting 3–4 cm away from the pylorus was performed. The entire length of the staple line was reinforced using 3.0 V-Loc suture by continuous suturing (V-Loc 180; Medtronic, Minneapolis, MN).
All patients were followed up at the 3rd, 6th and 12th months after LSG and annually thereafter during which laboratory tests and clinical assessment were done. Patients' baseline characteristics, co-morbidities, weight at the time of initial presentation, adherence to the low-calorie diet and weight measured with the same device on the morning of surgery were recorded. The patients who applied a low-calorie diet (1000 calories) for 2 weeks preoperatively were stratified into two groups. After evaluation of all patients, the percentage of mean total body weight loss (TBWL) was detected as 2.9% (0–11). Therefore, when grouping the patients according to the percentage of TBWL, 3% was taken as the cut-off value.
- Group A: Those who lost 3% or more of their total body weight
- Group B: Those who lost <3% of their total body weight.
Weight loss data are presented as per cent of excess weight loss (%EWL) and total weight loss (%TWL). For this calculation, the upper limit of BMI, i.e., 25 kg/m2 was taken as the reference value. The two groups were compared in terms of operative time, length of hospital stay, complications within the first 30 days after the surgery, BMI, %TWL and %EWL at 6 months, 1 year and 2 years postoperatively.
Statistical analysis was performed using SPSS software version 21 (IBM Corp. Armonk, NY, USA). Standard deviation and mean values were used for the variables with normal distribution and median values were used for the variables that were not normally distributed. Chi-square or Fisher's exact tests were used for categorical variables; while for continuous variables, independent-samples t-test or Mann–Whitney U-test were performed. P < 0.05 were considered statistically significant.
| ¤ Results|| |
A total of 305 patients underwent primary LSG between March 2018 and September 2020. The mean age of the patients was 37.8 ± 12 years (53% of females) and the mean BMI was 41.7 ± 7 kg/m2. At baseline, 79%, 11%, 30%, 53% and 23% of the patients had insulin resistance, type-2 diabetes mellitus, hypertension, hyperlipidaemia and obstructive sleep apnoea, respectively. With the 2-week diet before the surgery, 105 patients (35%) lost 3% or more of their total body weight (Group A), while 200 patients (65%) lost <3% of their total body weight (Group B). Median weight loss was 4 kg (3–20 kg). There was no weight loss in 108 patients in Group B and 19 patients gained weight during the pre-operative period (min: 1 kg, max: 5 kg). The demographics of both groups are shown in [Table 1].
Pre-operative mean BMI was 40 ± 7.4 kg/m2 in Group A and 41 ± 5.9 kg/m2 in Group B. There were more men in Group A (63%) and more women (61%) in Group B (P < 0.001). At 1 year after the surgery, BMI regressed to 29.7 ± 4.9 kg/m2 in Group A and to 27 ± 4.2 kg/m2 in Group B (P < 0.001). Among the 129 patients who completed 2 years of follow-up, mean BMI regressed to 29.4 ± 4.1 kg/m2 in Group A (n = 46) and to 27.2 ± 4.5 kg/m2 in Group B (n = 83) (P < 0.001). %EWL at 1 year after the surgery was 80 ± 22.4% in Group A and 93 ± 28.1% in Group B (P < 0.001).
In Group B, a patient with BMI 37 kg/m2 experienced post-operative bleeding. No other complication was observed in the study. Median operative time was 94 min (min: 80 max: 140) for Group A and 95 min (min: 70 max: 120) for Group B (P = 0.53). Furthermore, there was no significant difference between the groups in terms of length of hospital stay (P = 0.9). Post-operative outcomes of both groups are shown in [Table 2].
| ¤ Discussion|| |
Obesity has been rapidly increasing around the world, and accordingly, more patients are being operated for weight reduction every year. Several centres in this field are focused on constantly improving their bariatric surgery programmes, including the pre-operative preparation period, to reduce complication rates and achieve better outcomes. As part of these practices, patients in most centres apply a low-calorie diet for 2–3 weeks before surgery. Moreover, a relevant guideline supports weight loss before bariatric surgery. This practice primarily aims to reduce liver steatosis., It is thought that this may allow better visibility and more convenience during the surgery. Second, pre-operative diet is expected to improve patient compliance and aid in weight loss in the post-operative period. In this study, we concluded that losing weight before LSG had no effect and even had a negative effect on the success of post-operative weight loss (P < 0.001).
The comparison between patients who completed their 2-year follow-up after LSG also yielded the same result. Some studies on this subject matter have reported a positive relationship between pre-operative weight loss and post-operative weight loss, whereas, some other publications have reported no such association., Interestingly, a negative correlation was observed in a study involving patients with gastric bypass, similar to the findings of our study. In that study, it was observed that patients who succeeded in losing weight preoperatively lost less weight after the surgery.
A number of studies have reported that weight loss before bariatric surgery affects perioperative results, thereby shortening the operative time.,, Another study concluded that this practice improves visibility during the operation; although without any effect on operative time. In this study, there was no difference between the two groups in terms of operative time (P = 0.53). Although the shorter length of hospital stay was observed in patients with pre-operative weight loss in a study, many others reported no difference in length of hospital stay.,, Similarly, there was no difference between the two groups with regard to the length of hospital stay in the present study (P = 0.9).
The association between pre-operative weight loss and complications suggested in earlier publications remains unclear. Some studies have reported a higher rate of complications in patients who fail to lose weight preoperatively., A study in this field reported less blood requirement in patients who lost weight during the pre-operative period (1.4%–4.7%). Interestingly, the same study demonstrated a higher total rate of complications in those with pre-operative weight loss. In the present study, a patient in Group B, whose BMI was 37 kg/m2, experienced post-operative bleeding. This patient underwent reoperation and the bleeding focus was found to be short gastric vessels. Bleeding was stopped and the patient recovered without complications. There was no other complication in either group in our study.
Our study had some limitations such as being a retrospective study. Furthermore, gender distribution rates between the groups were not equal. While the rate of male participants was higher in Group A, the rate of female participants was higher in Group B. The primary purpose of the pre-operative diet is to reduce liver size and intraabdominal fat. Since abdominal obesity in men is at higher rates, it may have enabled them to apply the pre-operative diet more carefully. Similarly, the lower rate of abdominal obesity in women may be one of the reasons why the pre-operative diet was not followed properly; therefore the weight loss was less in Group B. In addition, the better weight loss rate of Group B in the follow-up period, unlike the pre-operative period, maybe due to the better adapting of women to the rules to be followed after surgery.
| ¤ Conclusion|| |
This study has shown that weight loss before LSG does not improve post-operative weight loss during a 2-year follow-up. Furthermore, weight loss before LSG was not associated with shorter operative time or length of hospital stay. More randomised prospective trials are needed to confirm these findings.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| ¤ References|| |
Sjöström L, Lindroos AK, Peltonen M, Torgerson J, Bouchard C, Carlsson B, et al
. Lifestyle, diabetes, and cardiovascular risk factors 10 years after bariatric surgery. N Engl J Med 2004;351:2683-93.
Folli F, Pontiroli AE, Schwesinger WH. Metabolic aspects of bariatric surgery. Med Clin North Am 2007;91:393-414, x.
Angrisani L, Santonicola A, Iovino P, Formisano G, Buchwald H, Scopinaro N. Bariatric surgery worldwide 2013. Obes Surg 2015;25:1822-32.
English WJ, DeMaria EJ, Brethauer SA, Mattar SG, Rosenthal RJ, Morton JM. American Society for Metabolic and Bariatric Surgery estimation of metabolic and bariatric procedures performed in the United States in 2016. Surg Obes Relat Dis 2018;14:259-63.
Pędziwiatr M, Kisialeuski M, Wierdak M, Stanek M, Natkaniec M, Matłok M, et al
. Early implementation of Enhanced Recovery after Surgery (ERAS®) protocol-Compliance improves outcomes: A prospective cohort study. Int J Surg 2015;21:75-81.
Małczak P, Pisarska M, Piotr M, Wysocki M, Budzyński A, Pędziwiatr M. Enhanced recovery after bariatric surgery: Systematic review and meta-analysis. Obes Surg 2017;27:226-35.
Edholm D, Kullberg J, Haenni A, Karlsson FA, Ahlström A, Hedberg J, et al
. Preoperative 4-week low-calorie diet reduces liver volume and intrahepatic fat, and facilitates laparoscopic gastric bypass in morbidly obese. Obes Surg 2011;21:345-50.
Colles SL, Dixon JB, Marks P, Strauss BJ, O'Brien PE. Preoperative weight loss with a very-low-energy diet: Quantitation of changes in liver and abdominal fat by serial imaging. Am J Clin Nutr 2006;84:304-11.
Cassie S, Menezes C, Birch DW, Shi X, Karmali S. Effect of preoperative weight loss in bariatric surgical patients: A systematic review. Surg Obes Relat Dis 2011;7:760-7.
Şen O, Türkçapar AG. Hair loss after sleeve gastrectomy and effect of biotin supplements. J Laparoendosc Adv Surg Tech A 2021;31:296-300.
Matłok M, Pędziwiatr M, Major P, Kłęk S, Budzyński P, Małczak P. One hundred seventy-nine consecutive bariatric operations after introduction of protocol inspired by the principles of enhanced recovery after surgery (ERAS®) in bariatric surgery. Med Sci Monit 2015;21:791-7.
Thorell A, MacCormick AD, Awad S, Reynolds N, Roulin D, Demartines N, et al
. Guidelines for perioperative care in bariatric surgery: Enhanced recovery after surgery (ERAS) society recommendations. World J Surg 2016;40:2065-83.
Alger-Mayer S, Polimeni JM, Malone M. Preoperative weight loss as a predictor of long-term success following Roux-en-Y gastric bypass. Obes Surg 2008;18:772-5.
Stefura T, Droś J, Kacprzyk A, Wierdak M, Proczko-Stepaniak M, Szymański M, et al
. Influence of preoperative weight loss on outcomes of bariatric surgery for patients under the enhanced recovery after surgery protocol. Obes Surg 2019;29:1134-41.
Carlin AM, O'Connor EA, Genaw JA, Kawar S. Preoperative weight loss is not a predictor of postoperative weight loss after laparoscopic Roux-en-Y gastric bypass. Surg Obes Relat Dis 2008;4:481-5.
Taylor EL, Chiasson PM, Perey BJ. Predicting bariatric surgical outcomes: Does preoperative weight gain correlate with lesser postoperative weight loss? Obes Surg 1995;5:375-7.
Riess KP, Baker MT, Lambert PJ, Mathiason MA, Kothari SN. Effect of preoperative weight loss on laparoscopic gastric bypass outcomes. Surg Obes Relat Dis 2008;4:704-8.
Alami RS, Morton JM, Schuster R, Lie J, Sanchez BR, Peters A, et al
. Is there a benefit to preoperative weight loss in gastric bypass patients? A prospective randomized trial. Surg Obes Relat Dis 2007;3:141-5.
Liu RC, Sabnis AA, Forsyth C, Chand B. The effects of acute preoperative weight loss on laparoscopic Roux-en-Y gastric bypass. Obes Surg 2005;15:1396-402.
Livhits M, Mercado C, Yermilov I, Parikh JA, Dutson E, Mehran A, et al
. Does weight loss immediately before bariatric surgery improve outcomes: A systematic review. Surg Obes Relat Dis 2009;5:713-21.
Van Nieuwenhove Y, Dambrauskas Z, Campillo-Soto A, van Dielen F, Wiezer R, Janssen I, et al
. Preoperative very low-calorie diet and operative outcome after laparoscopic gastric bypass: A randomized multicenter study. Arch Surg 2011;146:1300-5.
Still CD, Benotti P, Wood GC, Gerhard GS, Petrick A, Reed M, et al
. Outcomes of preoperative weight loss in high-risk patients undergoing gastric bypass surgery. Arch Surg 2007;142:994-8.
Benotti PN, Still CD, Wood GC, Akmal Y, King H, El Arousy H, et al
. Preoperative weight loss before bariatric surgery. Arch Surg 2009;144:1150-5.
[Table 1], [Table 2]