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Asian J Endosc Surg ISSN 1758-5902
O R I G I N A L A RT I C L E
Predictors of weight loss 2 years after laparoscopic sleeve gastrectomy David J Martin,1,3 Crystal MY Lee,2 Georgia Rigas3 & Charmaine S Tam2,4 1 Concord and Royal Prince Alfred Hospitals, University of Sydney, Sydney, New South Wales, Australia 2 The Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders, University of Sydney, Sydney, New South Wales, Australia 3 Strathfield Private Hospitals, University of Sydney, Sydney, New South Wales, Australia 4 The Charles Perkins Centre and School of Biological Sciences, University of Sydney, Sydney, New South Wales, Australia
Keywords Bariatric surgery; excess weight loss; sleeve gastrectomy Correspondence David Martin, Suite 2, 3 Everton Rd Strathfield, Sydney, NSW 2135, Australia. Tel: +61 2 9747 6166 Fax: +61 2 9745 1299 Email: [email protected] Received: 9 November 2014; revised 16 March 2015; accepted 24 March 2015 DOI:10.1111/ases.12193
Abstract Introduction: Despite the rapidly increasing popularity of laparoscopic sleeve gastrectomy (LSG), there is limited data examining weight loss more than 1 year after the procedure. There have also been few studies examining baseline predictors of weight loss after LSG. We aimed to examine the percentage of excess weight loss (%EWL) in patients 2 years after LSG and identify baseline predictors of %EWL. Methods: Electronic records from university hospitals were available for 292 patients who underwent LSG (205 women; mean age, 41.5 ± 11.1 years; mean weight, 126.5 ± 27.5 kg; mean BMI, 45.5 ± 7.5 kg/m2). Variables assessed for predictive effect were baseline age, sex, BMI, presence of comorbidities (diabetes, hypertension, or obstructive sleep apnea), the amount of weight loss induced by a very low-calorie diet before surgery, and the number of clinic appointments attended over the 2 years. We performed linear regression and mixed model analyses between predictor variables and %EWL at 2 years. Results: Adjusted %EWL was 31% at 2 weeks, 49% at 3 months, 64% at 6 months, 70% at 9 months, 76% at 12 months, 79% at 18 months, and 79% at 2 years. Multivariate analysis showed that lower baseline BMI, absence of hypertension, and greater clinic attendance predicted better %EWL (r2 = 0.11). Conclusion: Longer-term follow-up studies of weight loss post LSG are required to assist with patient care and management.
Introduction Bariatric surgery is the most successful long-term treatment for morbid obesity resulting in durable and substantial weight loss with improvement of obesity-related comorbidities. Over the past 10 years, laparoscopic sleeve gastrectomy (LSG) has steadily gained popularity as a primary procedure. First described by Hess and Marceau in the 1990s as part of the biliopancreatic diversionduodenal switch, SG was later popularized by Gagner et al., who used it as the first of two stages of laparoscopic Roux-en-Y gastric bypass (LRYGB) or duodenal switch in high-risk patients. Since then, the
328
number of LSG performed internationally has risen; in 2003, no procedures were performed, but within 10 years, 94 689 procedures were performed in 1 year (2011) (1). LSG is now commonly performed as a definitive procedure, and it has been shown to have similar weight loss and resolution of comorbidities as LRYGB after 6–12 months (2–4). Despite the growing popularity of LSG, there is a paucity of data available on the midterm efficacy of this procedure among larger cohorts (5,6). Given that patients who make significant longterm lifestyle changes will likely have optimal outcomes after the procedure, it would be beneficial to identify baseline characteristics, which are easily measurable in
Asian J Endosc Surg 8 (2015) 328–332 © 2015 Japan Society for Endoscopic Surgery, Asia Endosurgery Task Force and Wiley Publishing Asia Pty Ltd.
Weight loss 2 years after LSG
DJ Martin et al.
the clinic prior to surgery, to help predict weight loss after LSG. This information could be used as part of individualized preoperative assessments and to assist with resource allocation. The aim of our study was to examine weight loss results in a large patient population 2 years after LSG and to identify baseline predictors of percentage of excess weight loss (%EWL) after this surgery.
Materials and Methods We conducted an audit of data collected prospectively from electronic medical records (Genie; Magic Carpet Software, Australia) from 321 patients who underwent LSG performed by a single surgeon between August 2007 and October 2011. Patients were eligible for surgery if they had either a BMI >40 mg/kg2 or a BMI >35 mg/kg2 with weight-loss responsive comorbidities. Patients were excluded from data analysis if they had had previous gastric band surgery (n = 9), became pregnant during the 2-year follow-up period of the study (n = 8), had another type of operation after the initial surgery (n = 3), or had data collected only at baseline (n = 9). Data from 292 patients were available for analysis. This study was approved by the Human Research Ethics Committee at the Sydney Local Health District, Concord Repatriation General Hospital (Sydney, Australia). Patients provided informed consent, and patient anonymity was preserved. Surgical procedure and follow-up visits in clinic Patients had a standard work-up that included review with a multidisciplinary team and assessment of baseline anthropometric data. Before surgery, all patients were placed on a 2-week (3–4-week if BMI > 55), dietitianguided, very low-calorie diet using Optifast meal replacement (Nestle Australia, Rhodes, Australia). The surgical technique involved a non-antral-sparing LSG with a 29-Fr hollow bougie (Allergen, Parsippany, NJ) placed into the duodenum and stapling starting close to the pylorus and extending to the angle of His. Routine gastropexy-type sutures from the staple line to the omentum were used to decrease the risk of leakage from the tip and twisting elsewhere in the sleeve. Median hospital stay was 3 days. Postoperative follow-up was free for the patients and occurred at 2 weeks and 3, 6, 9, 12, 18, and 24 months.
Baseline weight was the maximum recorded weight measured by clinic staff before surgery. We also determined the amount of pre-surgery weight loss (absolute weight loss and %EWL) induced by the very low-calorie diet. Postoperative measures Body weight was measured at the clinic or self-reported over the phone at 2 weeks after LSG (n = 228) and at 3 (n = 181), 6 (n = 148), 9 (n = 131), 12 (n = 159), 18 (n = 128), and 24 months (n = 109) after LSG. Weight loss was calculated as the %EWL at each follow-up timepoint. This value was determined by subtracting the patient’s weight at follow-up from his or her baseline weight and then dividing this difference by the difference between the patient’s initial weight and his or her weight at a BMI of 25 kg/m2. The number of appointments attended was calculated from the total of the number of time-points at which each patient had his or her body weight measured; the maximum number of clinic visits over 2 years was seven. Statistics We conducted univariate regression analyses for each predictor (age, sex, BMI, presence of comorbidities at baseline, number of follow-up visits attended over 2 years, and degree of pre-surgery weight loss) against %EWL at 2 years to determine eligibility for inclusion into the multivariate analysis. Variables that had a P ≤ 0.10 in the univariate analyses were included in the base model for multiple regression analyses. The final model was obtained from a backward selection process in which variables with P > 0.05 were removed in a stepwise manner from the model. We then used mixed modeling to determine whether there was a significant change in %EWL over 2 years. All statistical analyses were performed using SAS 9.3 for Windows (SAS Institute, Cary, USA).
Results Medical records were available for 292 patients (205 women; mean age, 41.5 ± 11.1 years; mean weight, 126.5 ± 27.5 kg; mean BMI, 45.5 ± 7.5 kg/m2). Of these, 77 (26%) had type 2 diabetes, 102 (35%) had hypertension, and 54 (22%) had obstructive sleep apnea.
Baseline measures Age was calculated as the difference between the date of birth and date of surgery. Comorbidities (type 2 diabetes, obstructive sleep apnea, and hypertension) were classified as present or absent based on diagnoses listed in the patients’ notes and/or self-reported by the patient.
Predictors of %EWL 2 years after LSG Of the eight predictor variables tested, four had a P ≤ 0.10; these four variables were baseline age, baseline BMI, the presence of hypertension, and the number of clinic visits over 2 years after LSG (Table 1), all of which
Asian J Endosc Surg 8 (2015) 328–332 © 2015 Japan Society for Endoscopic Surgery, Asia Endosurgery Task Force and Wiley Publishing Asia Pty Ltd.
329
Weight loss 2 years after LSG
DJ Martin et al.
Table 1 Univariate regression models between predictor variables and %EWL 2 years after laparoscopic sleeve gastrectomy Predictor variables
β
P-value
r2
Age Sex Baseline weight Baseline BMI Pre-surgery weight loss Presence of diabetes Presence of OSA Presence of hypertension Number of appointments over 2 years
−0.5 −0.6 −0.2 0.8 −0.3 −4.9 −7.2 −10.4 4.6
0.07* 0.93 0.14 0.03* 0.56 0.48 0.31 0.09* 0.03*
0.03
Asian J Endosc Surg ISSN 1758-5902
O R I G I N A L A RT I C L E
Predictors of weight loss 2 years after laparoscopic sleeve gastrectomy David J Martin,1,3 Crystal MY Lee,2 Georgia Rigas3 & Charmaine S Tam2,4 1 Concord and Royal Prince Alfred Hospitals, University of Sydney, Sydney, New South Wales, Australia 2 The Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders, University of Sydney, Sydney, New South Wales, Australia 3 Strathfield Private Hospitals, University of Sydney, Sydney, New South Wales, Australia 4 The Charles Perkins Centre and School of Biological Sciences, University of Sydney, Sydney, New South Wales, Australia
Keywords Bariatric surgery; excess weight loss; sleeve gastrectomy Correspondence David Martin, Suite 2, 3 Everton Rd Strathfield, Sydney, NSW 2135, Australia. Tel: +61 2 9747 6166 Fax: +61 2 9745 1299 Email: [email protected] Received: 9 November 2014; revised 16 March 2015; accepted 24 March 2015 DOI:10.1111/ases.12193
Abstract Introduction: Despite the rapidly increasing popularity of laparoscopic sleeve gastrectomy (LSG), there is limited data examining weight loss more than 1 year after the procedure. There have also been few studies examining baseline predictors of weight loss after LSG. We aimed to examine the percentage of excess weight loss (%EWL) in patients 2 years after LSG and identify baseline predictors of %EWL. Methods: Electronic records from university hospitals were available for 292 patients who underwent LSG (205 women; mean age, 41.5 ± 11.1 years; mean weight, 126.5 ± 27.5 kg; mean BMI, 45.5 ± 7.5 kg/m2). Variables assessed for predictive effect were baseline age, sex, BMI, presence of comorbidities (diabetes, hypertension, or obstructive sleep apnea), the amount of weight loss induced by a very low-calorie diet before surgery, and the number of clinic appointments attended over the 2 years. We performed linear regression and mixed model analyses between predictor variables and %EWL at 2 years. Results: Adjusted %EWL was 31% at 2 weeks, 49% at 3 months, 64% at 6 months, 70% at 9 months, 76% at 12 months, 79% at 18 months, and 79% at 2 years. Multivariate analysis showed that lower baseline BMI, absence of hypertension, and greater clinic attendance predicted better %EWL (r2 = 0.11). Conclusion: Longer-term follow-up studies of weight loss post LSG are required to assist with patient care and management.
Introduction Bariatric surgery is the most successful long-term treatment for morbid obesity resulting in durable and substantial weight loss with improvement of obesity-related comorbidities. Over the past 10 years, laparoscopic sleeve gastrectomy (LSG) has steadily gained popularity as a primary procedure. First described by Hess and Marceau in the 1990s as part of the biliopancreatic diversionduodenal switch, SG was later popularized by Gagner et al., who used it as the first of two stages of laparoscopic Roux-en-Y gastric bypass (LRYGB) or duodenal switch in high-risk patients. Since then, the
328
number of LSG performed internationally has risen; in 2003, no procedures were performed, but within 10 years, 94 689 procedures were performed in 1 year (2011) (1). LSG is now commonly performed as a definitive procedure, and it has been shown to have similar weight loss and resolution of comorbidities as LRYGB after 6–12 months (2–4). Despite the growing popularity of LSG, there is a paucity of data available on the midterm efficacy of this procedure among larger cohorts (5,6). Given that patients who make significant longterm lifestyle changes will likely have optimal outcomes after the procedure, it would be beneficial to identify baseline characteristics, which are easily measurable in
Asian J Endosc Surg 8 (2015) 328–332 © 2015 Japan Society for Endoscopic Surgery, Asia Endosurgery Task Force and Wiley Publishing Asia Pty Ltd.
Weight loss 2 years after LSG
DJ Martin et al.
the clinic prior to surgery, to help predict weight loss after LSG. This information could be used as part of individualized preoperative assessments and to assist with resource allocation. The aim of our study was to examine weight loss results in a large patient population 2 years after LSG and to identify baseline predictors of percentage of excess weight loss (%EWL) after this surgery.
Materials and Methods We conducted an audit of data collected prospectively from electronic medical records (Genie; Magic Carpet Software, Australia) from 321 patients who underwent LSG performed by a single surgeon between August 2007 and October 2011. Patients were eligible for surgery if they had either a BMI >40 mg/kg2 or a BMI >35 mg/kg2 with weight-loss responsive comorbidities. Patients were excluded from data analysis if they had had previous gastric band surgery (n = 9), became pregnant during the 2-year follow-up period of the study (n = 8), had another type of operation after the initial surgery (n = 3), or had data collected only at baseline (n = 9). Data from 292 patients were available for analysis. This study was approved by the Human Research Ethics Committee at the Sydney Local Health District, Concord Repatriation General Hospital (Sydney, Australia). Patients provided informed consent, and patient anonymity was preserved. Surgical procedure and follow-up visits in clinic Patients had a standard work-up that included review with a multidisciplinary team and assessment of baseline anthropometric data. Before surgery, all patients were placed on a 2-week (3–4-week if BMI > 55), dietitianguided, very low-calorie diet using Optifast meal replacement (Nestle Australia, Rhodes, Australia). The surgical technique involved a non-antral-sparing LSG with a 29-Fr hollow bougie (Allergen, Parsippany, NJ) placed into the duodenum and stapling starting close to the pylorus and extending to the angle of His. Routine gastropexy-type sutures from the staple line to the omentum were used to decrease the risk of leakage from the tip and twisting elsewhere in the sleeve. Median hospital stay was 3 days. Postoperative follow-up was free for the patients and occurred at 2 weeks and 3, 6, 9, 12, 18, and 24 months.
Baseline weight was the maximum recorded weight measured by clinic staff before surgery. We also determined the amount of pre-surgery weight loss (absolute weight loss and %EWL) induced by the very low-calorie diet. Postoperative measures Body weight was measured at the clinic or self-reported over the phone at 2 weeks after LSG (n = 228) and at 3 (n = 181), 6 (n = 148), 9 (n = 131), 12 (n = 159), 18 (n = 128), and 24 months (n = 109) after LSG. Weight loss was calculated as the %EWL at each follow-up timepoint. This value was determined by subtracting the patient’s weight at follow-up from his or her baseline weight and then dividing this difference by the difference between the patient’s initial weight and his or her weight at a BMI of 25 kg/m2. The number of appointments attended was calculated from the total of the number of time-points at which each patient had his or her body weight measured; the maximum number of clinic visits over 2 years was seven. Statistics We conducted univariate regression analyses for each predictor (age, sex, BMI, presence of comorbidities at baseline, number of follow-up visits attended over 2 years, and degree of pre-surgery weight loss) against %EWL at 2 years to determine eligibility for inclusion into the multivariate analysis. Variables that had a P ≤ 0.10 in the univariate analyses were included in the base model for multiple regression analyses. The final model was obtained from a backward selection process in which variables with P > 0.05 were removed in a stepwise manner from the model. We then used mixed modeling to determine whether there was a significant change in %EWL over 2 years. All statistical analyses were performed using SAS 9.3 for Windows (SAS Institute, Cary, USA).
Results Medical records were available for 292 patients (205 women; mean age, 41.5 ± 11.1 years; mean weight, 126.5 ± 27.5 kg; mean BMI, 45.5 ± 7.5 kg/m2). Of these, 77 (26%) had type 2 diabetes, 102 (35%) had hypertension, and 54 (22%) had obstructive sleep apnea.
Baseline measures Age was calculated as the difference between the date of birth and date of surgery. Comorbidities (type 2 diabetes, obstructive sleep apnea, and hypertension) were classified as present or absent based on diagnoses listed in the patients’ notes and/or self-reported by the patient.
Predictors of %EWL 2 years after LSG Of the eight predictor variables tested, four had a P ≤ 0.10; these four variables were baseline age, baseline BMI, the presence of hypertension, and the number of clinic visits over 2 years after LSG (Table 1), all of which
Asian J Endosc Surg 8 (2015) 328–332 © 2015 Japan Society for Endoscopic Surgery, Asia Endosurgery Task Force and Wiley Publishing Asia Pty Ltd.
329
Weight loss 2 years after LSG
DJ Martin et al.
Table 1 Univariate regression models between predictor variables and %EWL 2 years after laparoscopic sleeve gastrectomy Predictor variables
β
P-value
r2
Age Sex Baseline weight Baseline BMI Pre-surgery weight loss Presence of diabetes Presence of OSA Presence of hypertension Number of appointments over 2 years
−0.5 −0.6 −0.2 0.8 −0.3 −4.9 −7.2 −10.4 4.6
0.07* 0.93 0.14 0.03* 0.56 0.48 0.31 0.09* 0.03*
0.03
