Effects of intragastric balloon placement in metabolic dysfunction-associated fatty liver disease: A systematic review and meta-analysis

Table 1 Search strategy

Search strategy
Medline	[(intragastric OR bariatric endoscopy OR balloon OR balloons OR bubble OR bubbles OR gastric balloon OR balloons)] AND [(mafld OR non alcoholic fatty liver disease OR nafld OR fatty liver OR nonalcoholic steatohepatitis OR nash OR nonalcoholic steatohepatitis OR alanine transaminase OR aspartate aminotransferase OR gamma-glutamyltransferase OR alkaline phosphatase OR fatty liver OR steatohepatitis OR steatohepatitis OR steatosis of liver OR visceral steatosis OR visceral]
MEDLINE, Embase, Cochrane, LILACS	[(intragastric OR balloon)] AND [(fatty liver)]
Grey literature	[(intragastric OR balloon)] AND [(fatty liver)]

Table 2 Grading recommendations assessment, development and evaluation certainty evidence assessment table

	Certainty evidence assessment							Study event rates (%)
	Participants (studies) follow up	Risk of bias	Inconsistency	Indirectness	Imprecision	Publication bias	Overall certainty of evidence	With post-IGB	With pre-IGB	Risk difference with Pre-IGB
ALT	1114 (10 observational studies)	Not serious	Serious1	Not serious2	Not serious	Publication bias strongly suspected3	⨁⨁◯◯, Low	557	557	Mean 10.27 UI/L more (8.25 more to 12.29 more)
GGT	1014 (8 observational studies)	Not serious	Not serious	Not serious2	Not serious	None	⨁⨁⨁⨁, High	507	507	Mean 9.23 UI/L more (6.88 more to 11.58 more)
Hb1Ac	300 (6 observational studies)	Not serious	Not serious	Not serious4	Not serious	Publication bias strongly suspected3	⨁⨁⨁◯, Moderate	150	150	Mean 0.17 % higher (0.03 higher to 0.31 higher)
Triglycerides	564 (6 observational studies)	Not serious	Not serious	Not serious	Not serious	None	⨁⨁⨁⨁, High	282	282	Mean 38.58 mg/dL higher (26.65 higher to 50.51 higher)
Systolic blood pressure	468 (3 observational studies)	Not serious	Not serious	Not serious	Not serious	None	⨁⨁⨁⨁, High	234	234	Mean 7.27 mmHg higher (4.79 higher to 9.76 higher)
HOMA-IR	378 (5 observational studies)	Not serious	Serious1	Not serious	Not serious	None	⨁⨁⨁◯, Moderate	189	189	Mean 2.07 higher (1.64 higher to 2.49 higher)
BMI	912 (8 observational studies)	Not serious	Not serious	Not serious	Not serious	Strong association	⨁⨁⨁⨁, High	456	456	Mean 5.07 kg/m2 higher (4.21 higher to 5.94 higher)
Waist	672 (7 observational studies)	Not serious	Not serious	Not serious	Not serious	None	⨁⨁⨁⨁, High	336	336	Mean 12.12 cm higher (9.82 higher to 14.41 higher)
Liver volume	32 (2 observational studies)	Not serious	Not serious	Not serious	Serious5	None	⨁⨁⨁◯, Moderate	16	16	MD 303.24 higher (56.66 lower to 663.15 higher)

¹Heterogeneity > 50%.

²Indirect measurement of hepatic steatosis.

³Presence of Outlier.

⁴Surrogate endpoint.

⁵Wide confidence interval. Overall certainty of evidence definition: ⨁◯◯◯: Very low-Any estimate of effect is very uncertain; ⨁⨁◯◯: Low-Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate; ⨁⨁⨁◯: Moderate-Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate; ⨁⨁⨁⨁: High-Further research is very unlikely to change our confidence in the estimate of effect; MD: Mean difference; IGB: Intragastric balloon; HbA1c: Glycated hemoglobin; ALT: Alanine aminotransferase; GGT: Gamma-glutamyltransferase; HOMA-IR: Homeostatic model; BMI: Body mass index.

Table 3 Results of individual studies

Ref.	n	Balloon volume (cm3)	ALT (UI/L)		GGT (UI/L)		HbA1c (%)		Triglycerides (mg/dL)		Waist (cm)		HOMA-IR		BMI (kg/m2)		SBP (mmHg)
			Pre-IGB	Post-IGB	Pre-IGB	Post-IGB	Pre-IGB	Post-IGB	Pre-IGB	Post-IGB	Pre-IGB	Post-IGB	Pre-IGB	Post-IGB	Pre-IGB	Post-IGB	Pre-IGB	Post-IGB
Forlano et al[25], 2010	120	500	39.3 (25.6)	24.4 (10.0)	37.5 (20.5)	24.5 (17.1)	-	-	-	-	-	-	-	-	43.1 (8.0)	38.8 (8.0)	-	-
Bazerbachi et al[22], 2021	21	-	91.6 (59.9)	39.4 (25.4)	-	-	7.7 (1.6)	6.5 (1.2)	-	-	128.9 (15.4)	119.7 (16.9)	-	-	43.2 (6.8)	37.9 (6.6)	-	-
Nikolic et al[21], 2011	33	600	30 (23.25)	27 (16.75)	31 (50.75)	21 (36.75)	4.7 (0.50)	4.6 (0.45)	124 (86.25)	124 (124.75)	122 (21.00)	110 (14.25)	-	-	41.4 (5.25)	35.6 (5.25)	-	-
Donadio et al[23], 2009	40	500	30.7 (14.0)	23.4 (9.3)	29.8 (19.1)	28.0 (28.1)	5.4 (0.5)	5.3 (0.4)	134.1 (67.8)	118.8 (66.5)	125.9 (18.6)	115.8 (17)	4.1 (2.1)	2.7 (1.6)	44.8 (8.9)	38.9 (6.8)	129.3 (14.0)	122.6 (10.4)
Stimac et al[29], 2011	166	600	34.7 (31.5)	26.5 (23.1)	33.3 (23.3)	24.7 (16.9)	-	-	118.6 (87.6)	81.0 (66.4)	127.8 (16.7)	113.3 (18.9)	-	-	41.6 (7.5)	35.8 (7.9)	130.9 (14.5)	124.2 (14.1)
Takihata et al[20], 2014	8	Variable	57.1 (55.6)	43.1 (48.8)	53.0 (25.4)	40.1 (19.3)	6.70 (1.43)	6.38 (1.49)	223.2 (194.8)	153.2 (80.6)	129.2 (8.3)	123.8 (12.3)	12.3 (10.9)	8.0 (7.3)	45.2 (5.9)	41.0 (6.2)	-	-
Folini et al[24], 2014	40	-	25.9 (10.31)	18.1 (5.96)	27.8 (27.57)	17.9 (12.21)	6.5 (1.17)	6.0 (0.74)	-	-	130.2 (13.96)	118 (13.01)	5.2 (2.23)	2.3 (1.66)	43.8 (6.62)	38.2 (6.19)	-	-
Ricci et al[26], 2008	65	-	31.5 (19.33)	24.0 (10.67)	31.0 (16.05)	23.5 (12.6)	-	-	-	-	-	-	4.71 (2.11)	3.10 (2.79)	-	-	-	-
Sekino et al[27], 2011	8	1000	74.2 (49.67)	56.7 (42.40)	57.00 (23.11)	41.25 (14.74)	6.30 (1.15)	6.31 (1.29)	251 (168.9)	163 (62.0)	-	-	6.74 (1.27)	3.27 (1.18)	-	-	-	-
Tai et al[28], 2013	28	500	49 (45.25)	22 (23.25)	-	-	-	-	149.0 (49.00)	88.5 (39.75)	101.9 (8.9)	90.6 (9.3)	-	-	32.4 (3.7)	28.5 (3.7)	136.8 (14.30)	125.9 (11.15)

IGB: Intragastric balloon; HbA1c: Glycated hemoglobin; ALT: Alanine aminotransferase; GGT: Gamma-glutamyltransferase; HOMA-IR: Homeostatic model; BMI: Body mass index; SBP: Systolic blood pressure.