The non-comparative analysis of the 44 articles included 49,848 patients, whereas 15,714 patients underwent ESG with 34,134 controls, including laparoscopic sleeve gastrectomy and adjustable gastric banding respectively intragastric balloons. The majority of patients were female, with 11,449 women (83.2%) and 2,304 men (16.8%) included in 42 articles (n = 13,753). The average baseline age and BMI were 44.24 years (SE 1.405, 95% CI 41.48–46.99; 41 articles, n = 13,562) and 37.56 (SE 0.45, 95% CI 36.66–38.46; 42 articles, n = 13,876), respectively.

Safety. The meta-analyses regarding the safety of ESG, revealed within 40 articles, reporting the occurrence of serious adverse events at a pooled rate of 1.25% (n = 194 events; amongst 15,398 ESG procedures). Within the currently available evidence, these results underline the safety of ESG with regard to short- and long-term results. Common adverse events associated with ESG include nausea, vomiting and abdominal discomfort. More serious adverse events have been associated with bleeding and perigastric fluid collection, which may require re-intervention. These were not distinguished in this particular source meta-analysis but are detailed in the underlying literature. [11].

Weight loss. The weight loss outcome parameters depending on the time points after ESG are summarised in Table 1. After 6 months, the %- excess weight loss (EWL) was nearly 48% (standard error 3.59, 95% CI 40.98–55.09, 24 articles, 4329 patients), respectively, the %- total body weight loss (TBWL) was about 16% (standard error 0.35, 95% CI 14.95—16.36, 33 articles, 5227 patients). During the maximum reported follow-up period of 5 years, the %EWL approximately reached 45 (standard deviation 47.32, 1 article, 56 patients) and 16% of TBWL (standard deviation 16.79, 1 article, 56 patients). Within the currently available evidence, these results underline the efficacy of ESG with regard to short- and medium-term outcomes of weight loss (Fig. 3).

Mean percentage of excess weight loss (%EWL) and total body weight loss (%TBWL) at specific time points following endoscopic sleeve gastroplasty (ESG). For context, the number of individuals and articles at each time point are included above the bars

Meta-analysis. Regarding the comparison of ESG and lifestyle intervention, two studies were eligible for quantitative synthesis and qualitative analysis, respectively. The first one, a case-matched cohort study (1 ESG: 2–3 controls), was published in 2020 by Cheskin et al. [13] and included patients with obesity grad I or higher. Authors compared ESG combined with low-intensity diet and lifestyle therapy (LIDLT) against high-intensity diet and lifestyle therapy (HIDLT). Costs were covered by the patients themselves, with a total amount of 16,000 $ for ESG and 3200 $ HIDLT. In total, 386 patients (105 ESG, 281 controls) were enrolled with comparable baseline characteristics, with the final follow-up at 1 year. The second one, a multi-centre, US FDA-regulated, open-label, RCT, was published in 2022 by Abu Dayyeh et al. and only included patients with obesity grade I and II [12]. The authors compared ESG plus lifestyle interventions with lifestyle interventions alone (MERIT Trial). Patients were randomly assigned to ESG or control groups in a 1:1.5 ratio. In total, 209 patients (85 ESG, 124 controls) were included, also with similar baseline characteristics. Within the MERIT Trial, the primary endpoints were %EWL and %TBWL at 1 year, with an extended follow-up at 24 months for the intervention group and a 12-month follow-up for patients in the control group crossing over to the intervention group. As per the Cochrane Handbook, data from different study designs should not be combined when only a few eligible studies are available. Consequently, due to the fact that the two studies differ in design (case-matched cohort study vs. RCT) and population (non-specified obesity vs. grade I and II), the data were analysed separately. The case-matched cohort study by Cheskin et al. [13] revealed after 12 months, a mean difference in %TBWL of 6.3 [95% CI 3.12–9.48] after ESG with LIDLT (mean:20.6, SD:8.3; n = 43) compared to the control group with HIDLT (mean:14.3, SD:10.2; n = 101). The RCT by Abu Dayyeh et al. [12] showed, after 12 months, a mean difference in %EWL of 46.00 [95% CI 38.05–53.95] and a mean difference in %TBWL of 13.10 [95% CI 11.08–15.12] after ESG combined with lifestyle interventions (%EWL—mean: 49.2, SD:32; and %TBWL—mean:13.6, SD:8; n = 77) compared to lifestyle interventions alone (%EWL—mean:3.2, SD:18.6; and %TBWL—mean:0.5, SD:5; n = 110). Regarding the occurrence of serious adverse events, the rate was 2% without mortality or need for intensive care or surgery intervention.

It has to be taken into account that the review included many observational studies, despite being of very low quality of evidence, reported consistently positive outcomes across various global settings, demonstrating ESG’s reproducibility and generalizability. A single RCT was included in the meta-analysis and provided moderate quality of evidence, further validating ESG’s efficacy and safety. This combination of evidence supports the IFSO’s 2023 Delphi Consensus statement on ESG’s role in obesity care.

Indications. The above-mentioned IFSO statements have been developed for the purpose of defining the specific indications for the ESG in the context of obesity treatment. In 2023, all available evidence was presented to a multidisciplinary committee of experts convened on behalf of the IFSO. Using a Delphi method, recommendations on the usefulness of ESG for the management of obesity were agreed and endorsed by the expert conference. Based on the presented data, the IFSO consensus supports ESG as an effective intervention over lifestyle alone in patients with obesity grades I and II and those with grade III who are unwilling or ineligible for conventional MBS (Table 2), as this minimally invasive procedure achieves significant short- and medium-term %EWL and %TBWL combined with a low rate of serious adverse events, and therefore a reasonable risk profile.

Notably, the expert committee, which included as well paediatric endocrinologists, also endorsed for the first time the use of the procedure to treat adolescents with class II obesity who have not responded to conservative therapy [14].

In general, the endoscopic procedure should be complemented by a multidisciplinary obesity programme. These statements by the IFSO Consensus Committee (Table 2) were confirmed by the consensus statements of the UK National Institute for Health and Care Excellence (NICE) guidelines, which also made almost identical recommendations on the benefits of ESG in the adult population, based on their own analysis of the evidence (Table 3).

These are the two most important consensus statements available that the ESG recommends for a clearly defined range of indications.