OBES SURG DOI 10.1007/s11695-014-1303-1
REVIEW ARTICLE
A Meta-analysis of 2-Year Effect After Surgery: Laparoscopic Roux-en-Y Gastric Bypass Versus Laparoscopic Sleeve Gastrectomy for Morbid Obesity and Diabetes Mellitus Chengda Zhang & Yuan Yuan & Cuiqiong Qiu & Weidong Zhang
# Springer Science+Business Media New York 2014
Abstract Literature search was performed for bariatric surgery from inception to September 2013, in which the effects of laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic sleeve gastrectomy (LSG) on body mass index (BMI), percentage of excess weight loss (EWL%), and diabetes mellitus (DM) were compared 2 years post-surgery. A total of 9,756 cases of bariatric surgery from 16 studies were analyzed. Patients receiving LRYGB had significantly lower BMI and higher EWL% compared with those receiving LSG (BMI mean difference (MD) = −1.38, 95 % confidence interval (CI) = −1.72 to −1.03; EWL% MD = 5.06, 95 % CI = 0.24 to 9.89). Improvement rate of DM was of no difference between the two types of bariatric surgeries (RR = 1.05, 95 % CI = 0.90 to 1.23). LRYGB had better long-term effect on body weight, while both LRYGB and LSG showed similar effects on DM.
Chengda Zhang and Yuan Yuan contributed equally to this work C. Zhang Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, People’s Republic of China Y. Yuan Department of Preventive Medicine, Zhengzhou Health School, Zhengzhou, Henan, People’s Republic of China C. Qiu School of Nursing, Guang Dong Food and Drug Vocational College, Guangdong, Guangzhou, People’s Republic of China W. Zhang (*) Department of Epidemiology, School of Public Health, Zhengzhou University, No.100 Kexue Avenue, Zhengzhou, Henan 450001, People’s Republic of China e-mail: [email protected]
Keywords Laparoscopic gastric bypass . Laparoscopic sleeve gastrectomy . Diabetes . Obesity . Bariatric surgery . Meta-analysis
Introduction Obesity is the major risk factor for a series of chronic conditions, such as diabetes mellitus, hypertension, dyslipidemia, and coronary artery disease. Globally, it ranks as the fifth leading risk for death, posing a significant threat to public health, longevity, and quality of life [1]. Due to the limited efficacy of noninvasive treatment, highly effective surgical procedures have been considered for obese patients with a body mass index (BMI) of at least 40 and for less obese patients with severe comorbidities plus a BMI of at least 35 [2]. Laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic sleeve gastrectomy (LSG) were the two most commonly bariatric surgical techniques used worldwide in 2011, and both are associated to a significant higher rate of remission of type 2 diabetes mellitus (DM) and hypertension compared with conventional therapy [3–5]. Although LRYGB remains to be the most commonly performed bariatric surgery, LSG is gaining popularity as a procedure with less adverse effects [6–8]. Both procedures have advantages and disadvantages [9, 10] and thus need to be carefully examined and compared. Given the chronic nature of obesity and obesity-related complications, long-term observation is needed [10]. As most studies have come to a point where 2-year results are available, it is now necessary and appropriate to do an updated meta-analysis on these inconsistent long-term results [11–13] to better guide clinical decisions. In this article, we sought to
OBES SURG
clarify the 2-year clinical outcomes of LRYGB and LSG for obesity as well as for DM through meta-analysis. To the best of our knowledge, this is by far the longest-term meta-analysis comparing LRYGB and LSG.
and improvement rate (defined as the sum of remission rate and cure rate) of type 2 DM 2 years after surgery. Efforts were made to get exact numerical data from authors via e-mail if not available in articles. We also tried to get numerical data by measuring charts in articles with tools provided by PDF viewer.
Materials and Methods Statistical Analysis Search Strategy for the Identification of Studies Electronic literature search was performed on PubMed, EMBASE, Wanfang, and China National Knowledge Infrastructure (CNKI) database from inception to September 3, 2013. The following medical subject headings (MeSH) and keywords were used: “laparoscopic Rouxen-Y gastric bypass” AND “laparoscopic sleeve gastrectomy” AND “obesity”. References of the chosen literatures were reviewed manually. Due to the limited information delivered by abstracts, we included only literatures with full texts available. Inclusion and Exclusion The studies included were as follows: (1) randomized controlled trials (RCTs), controlled clinical trials (CCTs), cohort studies or retrospective observational studies regardless of publication date; (2) with all participants diagnosed with obesity and (or) type 2 DM before surgery; and (3) with bariatric surgeries done laparoscopically. Studies with the following conditions were excluded: (1) unreliable design or obvious statistical mistakes as evaluated by two independent investigators; (2) only one kind of bariatric surgery included; (3) neither 2year outcome of obesity nor type 2 DM presented as outcome variables; (4) no full text available; and (5) participants receiving other gastric surgeries due to conditions other than obesity.
Heterogeneity of included studies was evaluated by chi-square test. If no significant heterogeneity was found (P>0.10, I2 > 50 %), the fixed effect model was used for data analysis. We investigated the source of heterogeneity and applied subgroup analysis when there was significant heterogeneity (P≤0.10, I2 >50 %). If the heterogeneity still existed, random effect model would be applied. We used fixed effect model or random effects model to evaluate the sensitivity. We assessed publication bias by creating funnel plots for the mean difference (MD) in BMI change, EWL%, and type 2 DM remission rate [15]. Relative risk (RR) or risk difference (RD) was calculated for categorical variables, while standardized MD was calculated for numerical variables.
Results Systematic Review Search Yields We got 246 search results from MEDLINE, 320 results from EMBASE, and 181 results from Wanfang and CNKI. Sixteen studies were finally included [12, 14, 16–29]. The flow chart for study selection is shown in Fig. 1. All selected articles were published in English. Study Characteristics
Quality Assessment Two investigators evaluated the quality of studies based on Cochrane reviewer’s handbook 5.1.0 independently. The quality evaluation chart from Xuechao Yang et al. [14] was adjusted and applied. Any dispute was solved unanimously through discussion. The criteria are introduced in more details in Table 1. The profile of each study was recorded into our database as follows: (1) basic information (authors, original country, date of publication, study design, sample size, duration of followup); (2) baseline information of participants (age, gender, and BMI); (3) type of bariatric surgery; and (4) follow-up data including time of follow-up and number of loss of follow-up. We captured the following outcome variables: BMI, EWL%,
Among all 16 included studies, 1 was randomized controlled trial and 15 were non-randomized (11 parallel controlled trials, 4 retrospective observational studies). A total of 9,756 cases were reported. Studies were conducted in Spain (5), USA (3), Japan (2), China (2), Switzerland (1), Greece (1), Slovenia (1), and Chile (1). Quality of Included Studies One study was randomized; all others were neither blinded nor randomized in grouping, intervention, data collection, or analysis. Although all studies tried to match patients by gender, age, and BMI at baseline, four studies still had significant difference in age or BMI, and one did not report complete
OBES SURG Table 1 Ratings of included studies Author
1a
2a
Wei-Jei Lee Violeta Moizé Pablo Vidal P. P. Cutolo David M. Lim Kazunori Kasama Ioannis Kehagias Simon KH Wong Camilo Boza David Benaiges Arthur M. Carlin Amanda Jiménez de Gordejuela AG M ohta
☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆
☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆
Breznikar B. Simone Gehrer
☆ ☆
☆ ☆
3a
☆ ☆
☆
4a aa
ba
☆
☆
☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆
☆ ☆ ☆ ☆
5a
6a
☆ ☆ ☆ ☆ ☆ ☆
☆
☆ ☆ ☆ ☆ ☆ ☆ ☆
7a
☆ ☆ ☆ ☆ ☆ ☆ ☆
☆ ☆ ☆
☆ ☆ ☆ ☆
☆ ☆
☆
☆
☆
☆
Sum
☆☆☆☆☆☆ ☆☆☆☆ ☆☆☆☆ ☆☆☆☆☆☆☆ ☆☆☆☆☆☆ ☆☆☆☆☆☆☆☆ ☆☆☆☆☆☆ ☆☆☆☆☆ ☆☆☆☆☆☆ ☆☆☆ ☆☆☆☆☆ ☆☆☆☆ ☆☆☆☆☆ ☆☆ ☆☆☆ ☆☆☆☆☆☆☆
a
The following criteria were used: 1. Is the case definition adequate? (If yes, one star) 2. Do the cases selected have a good representative? (If yes, one star; no star if there is potential for selection biases or not described) 3. Is there other history of related diseases? (If none, one star) 4. Comparability of cases and controls on the basis of the design or analysis (a) study controls for age, gender, and BMI (if yes, one star) (b) study controls for important factors: DM (If yes, one star) exposure 5. Clearly defined outcome of interest (if there is secure record, such as surgical records, one star; if structured interview was blind to case/control status, one star) 6. Is the method of ascertainment for cases and controls the same? (If yes, one star) 7. Adequacy of follow-up (one star, if follow-up >90 %)
baseline profile. We sent nine emails to authors for complete data and detailed study designs and got one reply. In four studies, we acquired numerical standard deviations indirectly by measuring charts in articles. All other studies lacking numerical data were excluded from the Fig. 1 Study screening and data extraction process
analysis. Few studies clearly mentioned how sample size was determined. All studies described the trial design, participants, interventions, outcomes, and statistical methods. The rate of loss of follow-up ranged from 0 to 81.1 %, with six studies not reporting. The results
OBES SURG
of quality assessment for 16 included articles are shown in Table 1. Patient Characteristics One study did not provide age, BMI, and gender data [30], while all others provided them with a comparison of complete baseline profiles between two treatment groups. The baseline characteristics of included articles are shown in Table 2. Meta-analyses and Heterogeneity
Change of Percentage of Excess Weight Loss A total of 14 articles reported EWL% 2 years after surgery. Excluding six lacking numerical standard deviations and three with significant baseline BMI difference, 2,182 patients (1,062 in LRYGB group, 1,120 in LSG group) from five studies were finally analyzed. Due to the existence of heterogeneity among included studies (P=0.004, I2 =74 %, Fig. 2b), random effects model was applied. Patients receiving LRYGB had a significantly higher EWL% 2 years after surgery compared with those receiving LSG [MD=5.06, 95 %CI (0.24, 9.89), Test for overall effect Z=2.06, P=0.04].
Change of BMI Improvement Rate of Type 2 DM Eight articles reported BMI 2 years after surgery, three of which lacking numerical standard deviation and one showing significant difference in BMI between two treatment groups at baseline. Finally, a total of 2,145 cases were analyzed from four studies, with 1,055 in LRYGB group and 1,090 in LSG group. No heterogeneity were found among studies (P=0.46, I2 =0 %, Fig. 2a). Patients have significantly lower BMI 2 years after LRYGB versus LSG [MD=−1.38, 95 % confidential interval (CI) (−1.72, −1.03), Test for overall effect, Z= 7.89, P
REVIEW ARTICLE
A Meta-analysis of 2-Year Effect After Surgery: Laparoscopic Roux-en-Y Gastric Bypass Versus Laparoscopic Sleeve Gastrectomy for Morbid Obesity and Diabetes Mellitus Chengda Zhang & Yuan Yuan & Cuiqiong Qiu & Weidong Zhang
# Springer Science+Business Media New York 2014
Abstract Literature search was performed for bariatric surgery from inception to September 2013, in which the effects of laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic sleeve gastrectomy (LSG) on body mass index (BMI), percentage of excess weight loss (EWL%), and diabetes mellitus (DM) were compared 2 years post-surgery. A total of 9,756 cases of bariatric surgery from 16 studies were analyzed. Patients receiving LRYGB had significantly lower BMI and higher EWL% compared with those receiving LSG (BMI mean difference (MD) = −1.38, 95 % confidence interval (CI) = −1.72 to −1.03; EWL% MD = 5.06, 95 % CI = 0.24 to 9.89). Improvement rate of DM was of no difference between the two types of bariatric surgeries (RR = 1.05, 95 % CI = 0.90 to 1.23). LRYGB had better long-term effect on body weight, while both LRYGB and LSG showed similar effects on DM.
Chengda Zhang and Yuan Yuan contributed equally to this work C. Zhang Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, People’s Republic of China Y. Yuan Department of Preventive Medicine, Zhengzhou Health School, Zhengzhou, Henan, People’s Republic of China C. Qiu School of Nursing, Guang Dong Food and Drug Vocational College, Guangdong, Guangzhou, People’s Republic of China W. Zhang (*) Department of Epidemiology, School of Public Health, Zhengzhou University, No.100 Kexue Avenue, Zhengzhou, Henan 450001, People’s Republic of China e-mail: [email protected]
Keywords Laparoscopic gastric bypass . Laparoscopic sleeve gastrectomy . Diabetes . Obesity . Bariatric surgery . Meta-analysis
Introduction Obesity is the major risk factor for a series of chronic conditions, such as diabetes mellitus, hypertension, dyslipidemia, and coronary artery disease. Globally, it ranks as the fifth leading risk for death, posing a significant threat to public health, longevity, and quality of life [1]. Due to the limited efficacy of noninvasive treatment, highly effective surgical procedures have been considered for obese patients with a body mass index (BMI) of at least 40 and for less obese patients with severe comorbidities plus a BMI of at least 35 [2]. Laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic sleeve gastrectomy (LSG) were the two most commonly bariatric surgical techniques used worldwide in 2011, and both are associated to a significant higher rate of remission of type 2 diabetes mellitus (DM) and hypertension compared with conventional therapy [3–5]. Although LRYGB remains to be the most commonly performed bariatric surgery, LSG is gaining popularity as a procedure with less adverse effects [6–8]. Both procedures have advantages and disadvantages [9, 10] and thus need to be carefully examined and compared. Given the chronic nature of obesity and obesity-related complications, long-term observation is needed [10]. As most studies have come to a point where 2-year results are available, it is now necessary and appropriate to do an updated meta-analysis on these inconsistent long-term results [11–13] to better guide clinical decisions. In this article, we sought to
OBES SURG
clarify the 2-year clinical outcomes of LRYGB and LSG for obesity as well as for DM through meta-analysis. To the best of our knowledge, this is by far the longest-term meta-analysis comparing LRYGB and LSG.
and improvement rate (defined as the sum of remission rate and cure rate) of type 2 DM 2 years after surgery. Efforts were made to get exact numerical data from authors via e-mail if not available in articles. We also tried to get numerical data by measuring charts in articles with tools provided by PDF viewer.
Materials and Methods Statistical Analysis Search Strategy for the Identification of Studies Electronic literature search was performed on PubMed, EMBASE, Wanfang, and China National Knowledge Infrastructure (CNKI) database from inception to September 3, 2013. The following medical subject headings (MeSH) and keywords were used: “laparoscopic Rouxen-Y gastric bypass” AND “laparoscopic sleeve gastrectomy” AND “obesity”. References of the chosen literatures were reviewed manually. Due to the limited information delivered by abstracts, we included only literatures with full texts available. Inclusion and Exclusion The studies included were as follows: (1) randomized controlled trials (RCTs), controlled clinical trials (CCTs), cohort studies or retrospective observational studies regardless of publication date; (2) with all participants diagnosed with obesity and (or) type 2 DM before surgery; and (3) with bariatric surgeries done laparoscopically. Studies with the following conditions were excluded: (1) unreliable design or obvious statistical mistakes as evaluated by two independent investigators; (2) only one kind of bariatric surgery included; (3) neither 2year outcome of obesity nor type 2 DM presented as outcome variables; (4) no full text available; and (5) participants receiving other gastric surgeries due to conditions other than obesity.
Heterogeneity of included studies was evaluated by chi-square test. If no significant heterogeneity was found (P>0.10, I2 > 50 %), the fixed effect model was used for data analysis. We investigated the source of heterogeneity and applied subgroup analysis when there was significant heterogeneity (P≤0.10, I2 >50 %). If the heterogeneity still existed, random effect model would be applied. We used fixed effect model or random effects model to evaluate the sensitivity. We assessed publication bias by creating funnel plots for the mean difference (MD) in BMI change, EWL%, and type 2 DM remission rate [15]. Relative risk (RR) or risk difference (RD) was calculated for categorical variables, while standardized MD was calculated for numerical variables.
Results Systematic Review Search Yields We got 246 search results from MEDLINE, 320 results from EMBASE, and 181 results from Wanfang and CNKI. Sixteen studies were finally included [12, 14, 16–29]. The flow chart for study selection is shown in Fig. 1. All selected articles were published in English. Study Characteristics
Quality Assessment Two investigators evaluated the quality of studies based on Cochrane reviewer’s handbook 5.1.0 independently. The quality evaluation chart from Xuechao Yang et al. [14] was adjusted and applied. Any dispute was solved unanimously through discussion. The criteria are introduced in more details in Table 1. The profile of each study was recorded into our database as follows: (1) basic information (authors, original country, date of publication, study design, sample size, duration of followup); (2) baseline information of participants (age, gender, and BMI); (3) type of bariatric surgery; and (4) follow-up data including time of follow-up and number of loss of follow-up. We captured the following outcome variables: BMI, EWL%,
Among all 16 included studies, 1 was randomized controlled trial and 15 were non-randomized (11 parallel controlled trials, 4 retrospective observational studies). A total of 9,756 cases were reported. Studies were conducted in Spain (5), USA (3), Japan (2), China (2), Switzerland (1), Greece (1), Slovenia (1), and Chile (1). Quality of Included Studies One study was randomized; all others were neither blinded nor randomized in grouping, intervention, data collection, or analysis. Although all studies tried to match patients by gender, age, and BMI at baseline, four studies still had significant difference in age or BMI, and one did not report complete
OBES SURG Table 1 Ratings of included studies Author
1a
2a
Wei-Jei Lee Violeta Moizé Pablo Vidal P. P. Cutolo David M. Lim Kazunori Kasama Ioannis Kehagias Simon KH Wong Camilo Boza David Benaiges Arthur M. Carlin Amanda Jiménez de Gordejuela AG M ohta
☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆
☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆
Breznikar B. Simone Gehrer
☆ ☆
☆ ☆
3a
☆ ☆
☆
4a aa
ba
☆
☆
☆ ☆ ☆ ☆ ☆ ☆ ☆ ☆
☆ ☆ ☆ ☆
5a
6a
☆ ☆ ☆ ☆ ☆ ☆
☆
☆ ☆ ☆ ☆ ☆ ☆ ☆
7a
☆ ☆ ☆ ☆ ☆ ☆ ☆
☆ ☆ ☆
☆ ☆ ☆ ☆
☆ ☆
☆
☆
☆
☆
Sum
☆☆☆☆☆☆ ☆☆☆☆ ☆☆☆☆ ☆☆☆☆☆☆☆ ☆☆☆☆☆☆ ☆☆☆☆☆☆☆☆ ☆☆☆☆☆☆ ☆☆☆☆☆ ☆☆☆☆☆☆ ☆☆☆ ☆☆☆☆☆ ☆☆☆☆ ☆☆☆☆☆ ☆☆ ☆☆☆ ☆☆☆☆☆☆☆
a
The following criteria were used: 1. Is the case definition adequate? (If yes, one star) 2. Do the cases selected have a good representative? (If yes, one star; no star if there is potential for selection biases or not described) 3. Is there other history of related diseases? (If none, one star) 4. Comparability of cases and controls on the basis of the design or analysis (a) study controls for age, gender, and BMI (if yes, one star) (b) study controls for important factors: DM (If yes, one star) exposure 5. Clearly defined outcome of interest (if there is secure record, such as surgical records, one star; if structured interview was blind to case/control status, one star) 6. Is the method of ascertainment for cases and controls the same? (If yes, one star) 7. Adequacy of follow-up (one star, if follow-up >90 %)
baseline profile. We sent nine emails to authors for complete data and detailed study designs and got one reply. In four studies, we acquired numerical standard deviations indirectly by measuring charts in articles. All other studies lacking numerical data were excluded from the Fig. 1 Study screening and data extraction process
analysis. Few studies clearly mentioned how sample size was determined. All studies described the trial design, participants, interventions, outcomes, and statistical methods. The rate of loss of follow-up ranged from 0 to 81.1 %, with six studies not reporting. The results
OBES SURG
of quality assessment for 16 included articles are shown in Table 1. Patient Characteristics One study did not provide age, BMI, and gender data [30], while all others provided them with a comparison of complete baseline profiles between two treatment groups. The baseline characteristics of included articles are shown in Table 2. Meta-analyses and Heterogeneity
Change of Percentage of Excess Weight Loss A total of 14 articles reported EWL% 2 years after surgery. Excluding six lacking numerical standard deviations and three with significant baseline BMI difference, 2,182 patients (1,062 in LRYGB group, 1,120 in LSG group) from five studies were finally analyzed. Due to the existence of heterogeneity among included studies (P=0.004, I2 =74 %, Fig. 2b), random effects model was applied. Patients receiving LRYGB had a significantly higher EWL% 2 years after surgery compared with those receiving LSG [MD=5.06, 95 %CI (0.24, 9.89), Test for overall effect Z=2.06, P=0.04].
Change of BMI Improvement Rate of Type 2 DM Eight articles reported BMI 2 years after surgery, three of which lacking numerical standard deviation and one showing significant difference in BMI between two treatment groups at baseline. Finally, a total of 2,145 cases were analyzed from four studies, with 1,055 in LRYGB group and 1,090 in LSG group. No heterogeneity were found among studies (P=0.46, I2 =0 %, Fig. 2a). Patients have significantly lower BMI 2 years after LRYGB versus LSG [MD=−1.38, 95 % confidential interval (CI) (−1.72, −1.03), Test for overall effect, Z= 7.89, P
