Table 2. Quality Assessment of the Included Studies.

Author	H.P.a Diagnosis	IBD Diagnosis	Study Type	Patient Enrollment	Outcome
el-Omar et al. (32)	IgG	Chart review	Prospective	Random	Primary
Mantzaris et al. (35)	Histology/RUT	Not reported	Prospective	Consecutive	Primary
Meining et al. (50)	Histology	Histology	Prospective	Consecutive	Secondary
Oberhuber et al. (41)	Histology	Histology	Prospective	Consecutive	Secondary
Parente et al. (33)	IgG/histology	Chart review	Prospective	Consecutive	Primary
Wagtmans et al. (31)	IgG	Chart review	Retrospective	Random	Primary
Duggan et al. (52)	IgG	Chart review	case-series	Consecutive	Primary
Corrado et al. (43)	IgG	Histology	Prospective	Consecutive	Secondary
D'Inca et al. (42)	Histology	Chart review	Prospective	Consecutive	Primary
Pearce et al. (34)	IgG/UBT	Radiology/histology	Prospective	Consecutive	Primary
Parente et al. (46)	UBT/histology	Chart review	Prospective	Consecutive	Primary
Parlak et al. (37)	Histology	Not reported	Prospective	Not reported	Primary
Vare et al. (40)	IgG	Chart review	Prospective	previous study	Primary
Feeney et al. (39)	IgG	Clinical criteria	Case-series	Matched	Primary
Furusu et al. (51)	IgG/histology	Histology	Prospective	Not reported	Secondary
Guslandi et al. (38)	IgG	Not reported	Not reported	Not reported	Primary
Pascasio et al. (44)	Histology	Histology	Retrospective	Consecutive	Secondary
Piodi et al. (47)	UBT	Chart review	Prospective	Consecutive	Primary
Triantafillidis et al. (36)	IgG	Chart review	Prospective	Not reported	Primary
Pronai et al. (48)	UBT	Histology	Prospective	Not reported	Primary
Oliveira et al. (53)	IgG/UBT	Histology	Prospective	Not reported	Primary
Oliveira et al. (49)	UBT	Histology	Prospective	Not reported	Primary
Sladek et al. (45)	Histology/RUT	Clinical/histology/serology	Not reported	Consecutive	Primary

^aH.P., Helicobacter pylori.

^bClinical criteria: authors state diagnoses were made according to “conventional clinical criteria.”