Table 1

Description of the included meta-analyses of associations between GORD and diverse diseases

Study, year	Outcomes	No. of studies	No. of cases	No. of participants	Method of GORD diagnosed	Type of metric*	Effect model	Effect estimate and 95% CI	P value of overall effects	P value of Q test	I²(%)	P value of Egger’s test	Quality assessment tool	AMSTAR 2 grading
Association between GORD and cancers
Rubenstein, 201941	OAC prevalence	5 CCS	566	3285	Symptom questionnaire and interview.	OR	Random	4.57 (3.89 to 5.36)	<0.05	0.36	6	0.139	NA	Critically low
Zhang, 201445	Pharyngeal cancer risk	2 CCS	4681	18 724	ICD-9 codes, symptomatic of GORD.	OR	Random	3.76 (0.21 to 67.48)	0.37	0.000	94	0.771	NA	Low
Parsel, 201840	Laryngeal malignancy risk	15 CCS	36 503	74 209	Symptom questionnaire, De Meester’s criteria, OGD, pH monitoring; RFS; RSI score.	OR	Random	2.37 (1.79 to 3.14)	<0.00001	<0.00001	95	0.528	MINORS	Moderate
Association between GORD and respiratory diseases
Havemann, 200737	Asthma prevalence	7 CSS	10 702	254 978	Questionnaire, physician interview and database review.	OR	Random	2.27 (1.81 to 2.84)	<0.05	0.000	85	0.062	NA	Critically low
Huang, 202038	COPD exacerbations risk	3 CCS	82	198	pH monitoring or symptom questionnaire.	OR	Fixed	5.37 (2.71 to 10.64)	<0.00001	0.96	0	0.696	AHRQ	Low
Leason, 201739	CRS prevalence	4 CCS	5391	219 670	Medical records and symptom questionnaire.	OR	Fixed	2.16 (1.37 to 3.48)	0.001	0.000	85.4	0.373	NA	Critically low
Bedard Methot, 201936	IPF risk	18 CCS	1760	12 574	Read code, pH monitoring and HARQ score.	OR	Random	2.94 (1.95 to 4.42)	<0.05	<0.00001	86	0.895	NOS	High
Wu, 201844	OSAHS prevalence	1 CCS; 3 CSS	416	1042	GORD questionnaire, pH monitoring, and OGD.	OR	Random	1.79 (1.00 to 3.22)	0.05	0.03	67	0.191	Chorane hand book	Low
Association between GORD and digestive diseases
Taylor, 201042	BO prevalence	26 CCS	NA	NA	Questionnaire and interview.	OR	Random	2.90 (1.86 to 4.54)	<0.05	0.0001	89	P†	NA	Low
Wijarnpreecha, 201743	NAFLD risk	4 CCS; 4 CSS	NA	31 322	Endoscopic assessment and reflux symptoms.	OR	Random	2.07 (1.54 to 2.79)	<0.00001	<0.00001	87	P‡	NOS	High

*Unadjusted OR, unless otherwise specified.
†The meta-analyses did not provide the p value of published bias but mentioned no published bias.
‡The meta-analyses did not provide the p value of published bias but mentioned existed published bias.
AHRQ, Agency for Healthcare Research and Quality ; BO, Barrett’s oesophagus; CCS, case-controlled studies; COPD, chronic obstructive pulmonary disease; CRS, chronic rhinosinusitis; CSS, cross-sectional study; GORD, gastro-oesophageal reflux disease; HARQ, Hull Airway Reflux Questionnaire Study; ICD-9, International Classification of Diseases; IPF, idiopathic pulmonary fibrosis; MINORS, Methodological Index for Non-randomized Studies; NAFLD, non-alcoholic fatty liver disease; NOS, Newcastle-Ottawa Scale; OAC, oesophageal adenocarcinoma; OGD, oesophagogast roduodenoscopy; OSAHS, obstructive sleep apnoea–hypopnoea syndrome; RFS, Reflux Finding Score; RSI, Reflux Symptom Index.