Keywords
GI surgery - Endoscopy Upper GI Tract - Quality and logistical aspects - Performance
and complications
Introduction
The rapidly growing disease burden of obesity necessitates the development, widespread
adoption, and increased utilization of newer therapeutic modalities. Several treatment
options other than lifestyle modifications have been developed over the last few decades
to combat this pandemic of obesity. These include anti-obesity medications (AOMs),
bariatric surgery, and endoscopic bariatric therapy (EBT). AOMs often represent the
initial treatment strategy for many patients, with currently nine US Food and Drug
Administration-approved medication options [1]. However, the efficacy of AOMs is limited and it is frequently not sustained after
discontinuation [2]. Bariatric surgery is the most effective therapeutic option for obesity and related
comorbidities. Unfortunately, due to limited access and utilization, only a small
fraction of eligible patients undergo bariatric surgery [3]
[4].
The last decade has seen the emergence of EBTs in the management of obesity. These
are novel, minimally invasive techniques and devices delivered endoscopically. Endoscopic
sleeve gastroplasty (ESG) is an innovative technique that uses an endoscopic suturing
device (OverStitch, Apollo Endosurgery, Austin, Texas, United States) to plicate the
greater curvature of the stomach ([Fig. 1]). It is an effective and safe technique for obesity, resulting in > 15% total body
weight loss (%TBWL) in the short and mid-term [5].
Fig. 1 Endoscopic sleeve gastroplasty. Panel includes Overstitch device, endoscopic and illustrative
appearance of the completed sleeve.
Performing ESG involves a high level of complexity and additional risks compared with
diagnostic procedures; hence, the American Society for Gastrointestinal Endoscopy
considers ESG a major skill [6]. In the United States, most endoscopists are gastroenterologists. However, endoscopy
is also an important part of the practice in bariatric surgery, thus more surgeons
have been gaining experience with ESG [7]. Given the increasing regulatory approval and global adoption, our aim is to evaluate
real-world outcomes and practice patterns comparing bariatric surgeons and gastroenterologists
in ESG performance across the United States.
Patients and methods
Study design, setting, and participants
We performed a retrospective analysis of patients who underwent ESG across seven different
sites in the United States from January 2013 through August 2022. These sites included
academic and private institutions, and procedures were performed by gastroenterologists
and bariatric surgeons. The institutional review board at the primary site approved
the study and waived the need for informed consent owing to its minimal-risk nature.
Institutional review board approval was also obtained at other sites. All adult patients
who had undergone ESG using a standard technique with the primary goal of weight loss
were included.
Study variables and data sources
Patient demographic and medical information were abstracted from the electronic medical
records. Indications for and technical details about each procedure were collected.
Baseline weight was defined as weight on the day of the intervention. Weight was recorded
at baseline, 6, 12, 18, and 24 months after the procedure. Both intra-procedure and
post-procedure adverse events (AEs) were recorded. %TBWL and %excess weight loss (%EWL,
based upon body mass index [BMI] = 25 kg/m2) were calculated based on baseline weight at the procedure. Responders to treatment
were defined as reaching a predetermined threshold for %TBWL at 12 and 24 months.
Each responder group included the number of patients that satisfy those criteria (i.e.,
10% = patients who achieved ≥ 10% TBWL). The patients were divided into groups based
on their provider (gastroenterologist or surgeon).
The primary aim of our study was to assess and compare weight loss outcomes in patients
in both groups. We also reviewed the procedure techniques and AEs between both groups.
Statistical analysis
All continuous data are summarized as means and 95% confidence intervals (CIs). Analyses
by provider type at each follow-up period were performed using one-way analysis of
variance with Bonferroni correction to identify significant comparisons or Chi-square.
Significance was defined as P<0.05. Imputation methods were used to evaluate the impact of missing data from the
results. The last observation carried forward (LOCF) reported the responder level
at the last recorded visit. Patients did not return for any visit were considered
non-responders at x% TBWL. The best-case scenario was defined such that subjects for
whom data were missing were considered responders at x% TBWL, while the worst-case
scenario was defined such that subjects for whom data were missing were not considered
responders at x% TBWL. SPSS (IBM Corp. Released 2021. IBM SPSS Statistics for Windows,
Version 29.0. Armonk, New York, United States: IBM Corp) was used for all statistical
analyses.
Results
Participants
Our cohort comprised 1506 patients with a mean age of 45.68 ± 10.25 years, predominantly
female (84.5%) and White (69.6%). Mean weight and BMI at baseline were 107.3 ± 21.42
kg and 38.43 ± 6.22 kg/m2, respectively. Two-hundred and thirty-five patients (15.6%) were treated by surgeons
and 1,271 patients (84.4%) by gastroenterologists.
Baseline characteristics
Baseline characteristics are described in [Table 1]. When divided by provider type, there was no difference with respect to sex, race,
or age between the two groups (P = 0.48, 0.49, and 0.23, respectively). There was a significant difference in the
percentage of patients that received medication co-therapy by provider type (15.7%
surgeons vs. 8.7% gastroenterologists, P < 0.001). Baseline weight, height, and BMI were similar between the groups.
Table 1 Baseline demographics by provider type.
|
Description
|
Surgeon
(N = 235)
|
Gastroenterologist
(N = 1271)
|
Total
(N = 1506)
|
|
CI, confidence interval; BMI, body mass index.
|
|
Sex
|
|
*
|
*
|
|
Male
|
37 (15.7%)
|
196 (15.4%)
|
233 (15.5%)
|
|
Female
|
198 (84.3%)
|
1074 (84.6%)
|
1272 (84.5%)
|
|
Race
|
|
|
|
|
N
|
45
|
1271
|
1316
|
|
White
|
28 (62.2%)
|
888 (69.9%)
|
916 (69.6%)
|
|
African American
|
6 (13.3%)
|
208 (16.4%)
|
214 (16.3%)
|
|
Asian
|
1 (2.2%)
|
22 (1.7%)
|
23 (1.7%)
|
|
Hispanic
|
5 (11.1%)
|
20 (1.6%)
|
25 (1.9%)
|
|
Other
|
1 (2.2%)
|
26 (2.0%)
|
27 (2.1%)
|
|
Not reported
|
4 (8.9%)
|
107 (8.4%)
|
111 (8.4%)
|
|
Obesity class
|
|
|
|
|
Class I
|
85 (36.2%)
|
416 (32.7%)
|
501 (33.3%)
|
|
Class II
|
78 (33.2%)
|
468 (36.8%)
|
546 (36.3%)
|
|
Class III
|
72 (30.6%)
|
387 (30.4%)
|
459 (30.5%)
|
|
Medication co-therapy
|
|
|
|
|
Yes
|
37 (15.7%)
|
110 (8.7%)
|
147 (9.8%)
|
|
No
|
198 (84.3%)
|
1161 (91.3%)
|
1359 (90.2%)
|
|
Age (years)
|
*
|
|
*
|
|
Mean (STD)
|
46.41 (9.95)
|
45.54 (10.31)
|
45.68 (10.25)
|
|
Min, max
|
19.0, 68.8
|
17.2, 73.6
|
17.2, 73.6
|
|
95% CI
|
45.1–47.7
|
45.0–46.1
|
45.2–46.2
|
|
Height (m)
|
|
|
|
|
Mean (STD)
|
1.67 (0.09)
|
1.67 (0.09)
|
1.67 (0.09)
|
|
Min, max
|
1.4–1.9
|
1.3–2.0
|
1.3–2.0
|
|
95% CI
|
1.66–1.68
|
1.66. 1.67
|
1.66–1.67
|
|
Weight (kg)
|
|
|
|
|
Mean (STD)
|
106.9 (21.17)
|
107.4 (21.47)
|
107.3 (21.42)
|
|
Min, max
|
72.1–190.8
|
66.2–240.4
|
66.2–240.4
|
|
95% CI
|
104.2–109.6
|
106.2–108.6
|
106.2–108.4
|
|
Ideal weight (kg)
|
|
|
|
|
Mean (STD)
|
69.7 (7.12)
|
69.7 (7.42)
|
69.7 (7.37)
|
|
Min, max
|
48.8–93.2
|
42.0–98.1
|
42.0–98.1
|
|
95% CI
|
68.8–70.7
|
69.3–70.1
|
69.4–70.1
|
|
Excess weight (kg)
|
|
|
|
|
Mean (STD)
|
37.1 (18.11)
|
37.6 (17.86)
|
37.6 (17.90)
|
|
Min, max
|
12.0–128.8
|
12.0–152.1
|
12.0–152.1
|
|
95% CI
|
34.8–39.5
|
36.7–38.6
|
36.7–38.5
|
|
BMI (kg/m2)
|
|
|
|
|
Mean (STD)
|
38.30 (6.40)
|
38.45 (6.19)
|
38.43 (6.22)
|
|
Min, max
|
30.00–76.93
|
30.04–111.10
|
30.00–111.10
|
|
95% CI
|
37.47–39.12
|
38.11–38.79
|
38.11–38.74
|
Procedure technique
We evaluated differences in procedural technique with respect to provider type ([Table 2]). Gastroenterologists used argon plasma coagulation for marking significantly more
often than surgeons (P < 0.001). Surgeons placed sutures in the fundus in all instances whereas gastroenterologists
placed them in the fundus in less than 1% of the cases (P < 0.001). There were no differences between provider types concerning the use of
the Overtube, adjunct therapy during the procedure, or intra-procedure complications
(< 1% for both groups). The mean number of sutures was seven, which was similar between
cohorts (P = 0.909). Procedure times were significantly different between groups, with surgeons
requiring approximately 20 minutes more during the procedure, compared with gastroenterologists
(P < 0.001).
Table 2 Procedure characteristics by provider type.
|
Description
|
Surgeon
(N = 235)
|
Endoscopist
(N = 1271)
|
Total
(N = 1506)
|
|
APC, argon plasma coagulation; CI, confidence interval.
|
|
Use of overtube
|
|
|
|
|
Yes
|
45 (19.1%)
|
252 (19.8%)
|
297 (19.7%)
|
|
No
|
190 (80.9%)
|
1019 (80.2%)
|
1209 (80.3%)
|
|
APC for marking
|
|
|
|
|
Yes
|
8 (3.4%)
|
442 (34.8%)
|
450 (29.9%)
|
|
No
|
227 (96.6%)
|
829 (65.2%)
|
1056 (70.1%)
|
|
Sutures in fundus
|
|
|
|
|
Yes
|
235 (100.0%)
|
5 (0.4%)
|
240 (15.9%)
|
|
No
|
0 (0%)
|
1265 (99.6%)
|
1265 (84.1%)
|
|
Adjunct therapy
|
|
|
|
|
Yes
|
0 (0%)
|
42 (3.4%)
|
42 (2.8%)
|
|
No
|
235 (100.0%)
|
1211 (96.6%)
|
1446 (97.2%)
|
|
Intra-procedure complications
|
|
|
|
|
Yes
|
1 (0.4%)
|
12 (0.9%)
|
13 (0.9%)
|
|
No
|
234 (99.6%)
|
1259 (99.1%)
|
1493 (99.1%)
|
|
Number of sutures
|
|
*
|
*
|
|
N
|
45
|
1231
|
1276
|
|
Mean (STD)
|
7.1 (1.7)
|
7.0 (2.21)
|
7.0 (2.19)
|
|
Min, max
|
5, 11
|
3, 28
|
3, 28
|
|
95% CI
|
6.6, 7.6
|
6.9, 7.2
|
6.9, 7.2
|
|
Procedure time (minutes)
|
|
|
|
|
N
|
90
|
942
|
1032
|
|
Mean (STD)
|
74.9 (20.18)
|
53.7 (26.40)
|
55.6 (26.59)
|
|
Min, max
|
17, 142
|
15, 205
|
15, 205
|
|
95% CI
|
70.7, 79.1
|
52.0, 55.4
|
53.9, 57.2
|
Weight loss outcomes by provider type
Weight loss parameters by provider type are reported for BMI, %TBWL, and %EWL ([Fig. 2]
a–c). The overall mean %TBWL was 15.4 (15.0, 15.7), 17.1 (16.6, 17.6), 16.8 (16.0, 17.6),
and 15.3 (14.3, 16.5) for 6, 12, 18, and 24 months, respectively. There was a significant
difference in %TBWL between the groups at 6 months (16.5% vs. 15.2%, P = 0.01), where patients treated by surgeons had higher weight loss. There was no
other significant difference in %TBWL outcomes between the two groups.
Fig. 2
a Percentage TBWL by provider type and time from procedure. b BMI by provider type and time from procedure. c Percentage EWL by provider type and time from procedure. d Responders at 12-month follow-up by provider type.
[Fig. 2]
d, [Table 3], and Supplementary Table 2S describe data concerning responders to treatment. At 12 and 24 months, a total of
83.2% and 69.9% of patients achieved ≥ 10% TBWL, respectively. Considering ≥ 15% TBWL,
60.9% and 46.3% of patients were responders at 12 and 24 months, respectively. When
analyzed by provider type, no significant differences were observed. Over 80% of patients
in both groups were responders at 12 months with TBWL ≥ 10% and over 50% were responders
with TBWL ≥ 15%. At 24 months, the percent responders decreased in both groups. Imputation
methods were used to evaluate the impact of missing data from the results. Only patients
who should have completed a 24-month visit were included in these imputation methods,
which included the LOCF, best-case scenario, and worst-case scenario ([Table 3]).
Table 3 Responders at 24-month follow-up by provider type.
|
Completers analysis
|
|
Responder definition
|
Surgeon
(n = 31)
|
Endoscopist
(n = 308)
|
Total
(n = 339)
|
|
10%
|
67.7% (21)
|
70.1% (216)
|
69.9% (237)
|
|
15%
|
32.3% (10)
|
47.7% (147)
|
46.3% (157)
|
|
20%
|
22.6% (7)
|
28.2% (87)
|
27.7% (94)
|
|
25%
|
9.7% (3)
|
16.6% (51)
|
15.9% (54)
|
|
30%
|
6.5% (2)
|
8.8% (27)
|
8.6% (29)
|
|
40%
|
0% (0)
|
3.2% (10)
|
2.9% (10)
|
|
Last observation carried forward (LOCF)
|
|
Responder definition
|
Surgeon
(n = 67)
|
Endoscopist
(n = 559)
|
Total
(n = 626)
|
|
10%
|
52.2% (35)
|
63.0% (352)
|
61.8% (387)
|
|
15%
|
29.9% (20)
|
41.0% (229)
|
39.8% (249)
|
|
20%
|
20.9% (14)
|
21.1% (118)
|
21.1% (132)
|
|
25%
|
9.0% (6)
|
10.7% (60)
|
10.5% (66)
|
|
30%
|
4.5% (3)
|
5.7% (32)
|
5.6% (35)
|
|
40%
|
0% (0)
|
2.0% (11)
|
1.8% (11)
|
|
Best-case scenario
|
|
Responder definition
|
Surgeon
(n = 67)
|
Endoscopist
(n = 559)
|
Total
(n = 626)
|
|
10%
|
85.1% (57)
|
83.5% (467)
|
83.7% (524)
|
|
15%
|
32.3% (10)
|
47.7% (147)
|
46.3% (157)
|
|
20%
|
22.6% (7)
|
28.2% (87)
|
27.7% (94)
|
|
25%
|
9.7% (3)
|
16.6% (51)
|
15.9% (54)
|
|
30%
|
6.5% (2)
|
8.8% (27)
|
8.6% (29)
|
|
40%
|
0% (0)
|
3.2% (10)
|
2.9% (10)
|
|
Worst-case scenario
|
|
Responder definition
|
Surgeon
(n = 67)
|
Endoscopist
(n = 559)
|
Total
(n = 626)
|
|
10%
|
31.3% (21)
|
38.6% (216)
|
37.9% (237)
|
|
15%
|
14.9% (10)
|
26.3% (147)
|
25.1% (157)
|
|
20%
|
10.4% (7)
|
15.6% (87)
|
15.0% (94)
|
|
25%
|
4.5% (3)
|
9.1% (51)
|
8.6% (54)
|
|
30%
|
3.0% (2)
|
4.8% (27)
|
4.6% (29)
|
|
40%
|
0% (0)
|
1.8% (10)
|
1.6% (10)
|
Adverse events
Only events that were reported as either device and/or procedure-related were included
in the analysis below (Supplementary Table 1S). Two-hundred and fifty-six patients experienced 360 events. A total of 173 patients
(73.6%) treated by surgeons experienced 134 events. A total of 83 patients (6.5%)
treated by gastroenterologists experienced 125 events.
Of note, one of the surgical sites reported the initial accommodative symptoms for
all patients (abdominal pain, nausea, vomiting), which were not reported by other
sites. However, there were no statistical differences in serious AEs (SAEs). Thirty-nine
patients (2.6%) experienced at least one AE requiring hospitalization (51 events)
for treatment: four patients with six events treated by surgeons (1.7%) and 35 patients
with 45 events treated by gastroenterologists (2.7%) (P > 0.05). The majority of these included pharmacological therapy for symptom management
and fluid replacement. Three of the 51 events (one from a surgeon and two from gastroenterologists)
required surgical interventions.
Discussion
Our data from a large US cohort showed significant and sustained weight loss with
ESG and excellent safety profiles for both bariatric surgery and gastroenterologist
practices. To the best of our knowledge, this is the first report of weight loss outcomes
analyzed by provider type. The %TBWL at 12 months for our cohort was 17% or higher
for patients in either group, which is consistent with previously reported weight
loss outcomes for ESG [5]
[8]. More than 80% of patients in both cohorts also had > 10% TBWL at 12 months, which
is generally considered the threshold for improvement of obesity-related comorbidities
[9].
At 6 months, patients treated by surgeons had a higher %TWL (16.5% vs. 15.2%, P = 0.010); however, this was not sustained at future time points. This initial difference
in weight loss may be attributable to the differences in procedure techniques between
provider types, increased use of AOMs by surgeons, and differences in multidisciplinary
teams. Also, despite being statistically different, one must consider if that is a
clinically relevant result. Our large sample at baseline allowed for the detection
of statistical significance even when the results are numerically similar (or not
clinically relevant). Regardless, outcomes at longer follow-up time points were similar
independent of the provider.
We noted that procedure techniques varied between types of providers. Surgeons placed
fundal sutures more frequently compared with gastroenterologists, who placed them
in < 1% of cases. Suturing the fundus yields a final anatomical appearance more similar
to a surgical sleeve gastrectomy, which is presumably the reason that surgeons choose
this technique. In addition, gastroenterologists are generally reluctant to suture
the fundus, given the thin wall thickness [10], and the fear of AEs such as leaks, perforation, and perigastric fluid collections,
and the contradictory benefit of it [11]. In our cohort, fundal suturing did not increase such AEs in the surgeon group;
actually, gastroenterologists reported a higher incidence of gastric perforation and
perigastric collections (4 [0.3%] and 2 [0.2%], respectively), compared with surgeons
(one gastric leak [0.4%]). Nonetheless, our study corroborates previous data showing
that fundal sutures result in no additional weight loss and lead to longer procedure
times [12]. There is also physiological evidence showing that the fundic pouch delays gastric
emptying and may be crucial in weight loss [13]. Currently, there is significant heterogeneity in endoscopy training between general
surgery, bariatric surgery, gastroenterology, and advanced endoscopy fellowships [14]
[15]. This may account for some of the technical differences noted between groups of
providers. As bariatric and metabolic endoscopy evolves as a field, further insight
into practice patterns of differently trained providers is warranted.
We also compared the safety of ESG among providers. The higher AE rate in patients
treated by surgeons can primarily be attributable to heterogeneity in the report.
One surgical site classified accommodative complaints on the day of the procedure
as AEs, while all other sites did not. Currently, mild-to-moderate nausea, cramps,
and abdominal pain are expected within the normal post-procedure course. Therefore,
most centers did not consider them AEs. Importantly, there were no differences in
the SAEs, and in fact, the rate was lower in the surgeon group. The consistency of
recording and reporting AEs in endoscopy continues to be a challenge, but is key to
assess safety of procedures and enable future research and comparisons [16]. One analysis of the Metabolic and Bariatric Surgery Accreditation and Quality Improvement
Program (MBSAQIP) database had findings of similar AE rates at 30 days, although they
reported that surgeons had a trend toward a higher rate of reoperations within 30
days, and patients treated by gastroenterologists had more emergency room visits [17]. In our study, the rates of SAEs are far below 5% in either group, which is the
standard of safety recommended by the American Society of Gastrointestinal Endoscopy,
further emphasizing the remarkable safety profile of ESG across practice settings
[18].
In the United States, the number of surgeons performing routine endobariatrics is
still limited, which accounts for the differences seen in the number of procedures
performed by groups in our cohort. However, as ESG and other endobariatric procedures
continue to evolve in their techniques and indications, many bariatric surgery practices
have an interest in incorporating these therapeutic modalities into their armamentarium.
Training in bariatric endoscopy is still in its infancy, with very few formal training
programs. Most providers interested in performing these procedures gain experience
through short apprenticeships or courses. The limited access to training modalities
may be one reason for the lower number of surgeons practicing bariatric endoscopy.
Although there are no specific thresholds for competency described in the literature,
one study describes the learning curve for an experienced endoscopist for ESG to be
29 to 38 procedures to attain efficiency, and 55 procedures to attain mastery [19]. However, these numbers will likely vary based on background endoscopy training
and the stage of the career of the provider. Different training tools like ex vivo
and live animal models are used routinely to supplement training; in the future, the
use of simulators and virtual reality platforms may standardize and improve access
to training in bariatric endoscopy.
Our study has several strengths. We used data from the largest cohort of patients
to have undergone ESG in the United States, with only a few other registries of this
scale across the globe [20]
[21]. Our data are gathered from seven different academic and private sites and, as such,
are fairly representative of the current practice of ESG in the United States. We
have a follow-up of 2 years and used multiple statistical models to compensate for
the attrition of patients. The inherent limitations of retrospective data are present
in our study. The number of procedures performed by surgeons compared with gastroenterologists
was significantly lower; however, it represents the current practice in the United
States. The effects of additional therapies, such as intensive lifestyle modification
or anti-obesity medication, were not considered during our analysis. Pharmacotherapy
after ESG usually prevents weight regain but does not lead to significant additional
weight loss; hence, we believe that our findings continue to be representative of
real-world outcomes [22].
Conclusions
There is an urgent need for expanding care for patients with obesity, with many reports
demonstrating an abysmally low rate of appropriate management [23]. ESG has gained global acceptability as a safe and effective treatment for obesity
[24]. In particular, it can be a viable option for patients who do not wish to undergo
bariatric surgery or who have upfront contraindications to surgery, and it could be
incorporated into multidisciplinary bariatric practice. Our data support the scalability
of this procedure across provider backgrounds and practices.
