Association of non-alcoholic fatty liver and metabolic-associated fatty liver with COVID-19 outcomes: A systematic review and meta-analysis

Table 1 Main characteristics of the included studies in the systematic review and meta-analysis

Serial No.	Ref.	Country	Study design	NAFLD, n	No NAFLD, n	mean ± SD	Male, n	Measure of NAFLD	Measure of NAFLD
1	Calapod et al[27]	Romania	Prospective descriptive study	47	79	66.32 ± 13.72	57.20%	Imaging evidence (ultrasound or computer tomography)	Biochemical enzymes (liver function test) within the past 12 mo
2	Campos-Varela et al[28]	Spain	Prospective observational (cohort) study	271	29	55.25 ± 11.69	49%	Liver steatosis by hepatic steatosis index	Transient elastography by controlled attenuation parameter
3	Chang et al[29]	South Korea	Retrospective cohort study	2082	1040	-	30.72%	FLI index
4	Chen et al[30]	United States	Retrospective single-center cohort study	178	164	62.6 ± 15.6	53.50%	Liver steatosis	Imaging evidence of steatosis > 30 d before COVID-19 diagnosis, or hepatic steatosis index
5	Çoraplı et al[31]	Turkey	Retrospective cohort study	106	308	-	56.04%	Hepatic-to-splenic attenuation ratio
6	Davidov-Derevynko et al[32]	Israel	Single center retrospective cohort study	47	335	58.6 ± 18.6	61%	Imaging, previous medical records, admission fibrosis-4	Prior liver enzymes
7	Demir et al[33]	Turkey	Retrospective cohort study	349	270	51.6 ± 9.65	58.60%	Fibrosis-4 index
8	Ji et al[34]	China	Cohort	19	35	43.6 ± 14.1	58.6	Fibrosis-4 index, APRI, ultrasound
9	Effenberger et al[35]	Austria	Prospective study	12	20	-	40.62%	Liver stiffness measurements and controlled attenuation parameter with a fibro scan	Liver and spleen sonography and elastography
10	Elfeki et al[36]	United States	Retrospective cohort study	88	285	63.3 ± 14.8	52%	Prior data lab values
11	Forlano et al[14]	United Kingdom	Retrospective cohort study	61	132	-	60%	Fibrosis-4 index	Imaging (either ultrasound or computerized tomography) or past medical history
12	Hashemi et al[37]	United States	Retrospective cohort	55	294	63.4 ± 16.5	55.4%	Hepatic steatosis on any prior imaging studies or liver histology
13	Huang et al[38]	China	Retrospective cohort study	86	194	43.6 ± 17.8	52.10%	Hepatic steatosis index
14	Hussain et al[39]	Pakistan	Cross sectional study	87	63	59.73 ± 11.35	56%	Clinical parameters like hepatomegaly and lab parameters like AST, ALT
15	Kim et al[40]	United States	Observational cohort study	456	411	56.9 ± 14.5	54.70%	Fibrosis by magnetic resonance elastography	Fibro scan, fibrosis-4, or biopsy
16	Madan et al[41]	India	Case control study	289	157	-	64.5%	Liver attenuation index
17	Marjot et al[42]	United States	Cohort study	322	367	58 ± 15.6	62.40%	Reported by clinician
18	Mushtaq et al[13]	Qatar	Prospective study	320	269	-	84.71%	Hepatic steatosis index
19	Romero-Cristóbal et al[43]	Spain	Prospective observational (cohort) study	81	96	59.58 ± 13.79	71.96	Fibrosis-4 index
20	Rentsch et al[44]	United States	Retrospective cohort study	377	139	65.8 ± 7.8	95.4	Fibrosis-4 index
21	Shao et al[45]	China	Observational cohort study	37	84	60.6 ± 13.5	64.46%	Liver enzyme/GGT twice upper limit of normal
22	Targher et al[46]	China	Cohort study	50	43	-	48%	Fibrosis-4	NAFLD fibrosis score
23	Tignanelli et al[47]	United States	Retrospective cohort study	934	25962	51 ± 23.7	56%	Elevated ALT level on 3 separate dates
24	Trivedi et al[48]	United States	Case control study	45	274	65 (median)	50%	Abdominal imaging (computed tomography, magnetic resonance imaging, or ultrasound)
25	Vázquez-Medina et al[49]	Mexico	Retrospective case control study	299	60	54.3 ± 14.69	22.01%	Fibrosis-4 index
26	Moctezuma-Velázquez et al[50]	Mexico	Retrospective cohort study	359	111	51.6 ± 14.8	63%	Computed tomography scans
27	Vrsaljko et al[51]	Republic of Croatia	Prospective observational (cohort) study	120	96	59.3 ± 12.6	63.43%	Ultrasound	Difference between liver and spleen computed tomography attenuation
28	Wang et al[52]	China	Retrospective cohort study	86	132	-	50.40%	Ultrasound parameters
29	Yao et al[53]	China	Retrospective cohort study	38	48	43.2 ± 15.45	58.10%	Hepatic steatosis index	NAFLD fibrosis score
30	Yoo et al[54]	South Korea	Retrospective cohort study	629	561	-	-	Hepatic steatosis index, FLI, claims based NAFLD
31	Younossi et al[55]	United States	Observational cohort study	553	2736	-	49.55%	Abdominal imaging, magnetic resonance imaging, computer tomography, ultra-sound
32	Zhou et al[56]	China	Cohort study	55	55	42.1 ± 11.4	74.50%	Computed tomography

Non-alcoholic fatty liver disease is used synonymously with metabolic-associated fatty liver disease in this table.

ALT: Alanine aminotransferase; APRI: Aminotransferase/platelet ratio index; AST: Aspartate aminotransferase; COVID-19: Coronavirus disease 2019; FLI: Fatty liver index; GGT: Gamma-glutamyl transferase; NAFLD: Non-alcoholic fatty liver disease.