Increased interleukin-6 is associated with long COVID-19: a systematic review and meta-analysis

Table 1 List of the studies used for the analysis of IL-6 levels in clinical COVID-19 and healthy individual groups

Study or Subgroup	Long COVID-19			Healthy control			Acute COVID-19			Non-PASC			D or I	St. Desi
Study or Subgroup	Mean	SD	N	Mean	SD	N	Mean	SD	N	Mean	SD	N	D or I	St. Desi
Acosta-Ampudia et al., 2022 [37]	31.88	31.64	12	3.83	4.01	8	64.75	101.40	60	NR	NR	NR	I	Coh
Barros et al., 2021 [36]	40.77	55.46	118	5.186˟	15.93	3166	NR	NR	NR	NR	NR	NR	I	RCT
Cervia et al., 2022 [38]	8.77	14.71	85	0.53	0.85	40	3.8	7.03	49	NR	NR	NR	I	Coh
Colarusso et al., 2021 [39]	141.75	83.47	52	280.75	195.41	17	NR	NR	NR	NR	NR	NR	I	Cros
Dugani et al., 2022 [40]	8.6	23.98	69	2.95	8.03	66	NR	NR	NR	NR	NR	NR	I	Cc
Ganesh et al., 2021 [41]	2.2	0.28	108	0.45	0.36	108	NR	NR	NR	NR	NR	NR	I	Cros
Karosanidze et al., 2022 [42]	5.883	3.919	50	5.186˟	15.93	3166	NR	NR	NR	NR	NR	NR	D	RCT
Littlefield et al., 2022 [43]	1.55	2.83	20	5.186˟	15.93	3166	NR	NR	NR	0.87	1.59	20	I	Coh
Montefusco et al., 2021 [44]	0.05	0.15	10	0.3	0.34	14	3.22	3.69	8	NR	NR	NR	D	Coh
Patterson et al., 2021 [34]	20.47	66.75	121	2.21	1.54	29	76.45	NR	74	NR	NR	NR	I	Coh
Peluso et al., 2021(a) [45]	11.75	39.52	73	5.186˟	15.93	3166	NR	NR	NR	8.91	8.08	48	D	Coh
Peluso et al., 2021(b) [45]	21.38	23.36	73	5.186˟	15.93	3166	NR	NR	NR	6.31	6.37	48	D	Coh
Queiroz et al., 2022 [13]	19.29	10.81	225	5.186˟	15.93	3166	47.235	32.50	92	NR	NR	NR	I	Coh
Taha et al., 2021 [35]	25.52	3.45	100	5.186˟	15.93	3166	NR	NR	NR	NR	NR	NR	D	Cros
Townsend et al., 2021 [46]	2.32	2.4	3	5.186˟	15.93	3166	17.06	21.80	22	NR	NR	NR	I	Coh
Vyas et al., 2021 [47]	35.91	0.0036	1	5.186˟	15.93	3166	NR	NR	NR	NR	NR	NR	D	Cr
Wechsler et al., 2021 [48]	1.76	1.1	13	0.71	0.48	20	19.31	19.35	19	1.06	0.56	13	I	Coh

Mean: mean value of IL-6 estimated in pg/ml
*, the normal value of IL-6 in healthy individuals according to a meta-analysis study [27], which was used for studies in which the IL-6 value for healthy individuals was not provided
SD: standard deviation of IL-6 values; N: number of participants for estimation in a study; (a) and (b), different cohorts from the same article; NR: not related or not reported; D: mean data extraction using the direct mean value of IL-6; I: mean data extraction using the indirect mean value of IL-6; St: Desi, study design; Coh: cohort study; Cc: case–control study; Cros: cross-sectional study; RCT: randomized controlled trial; Cr: case report

ISSN: 2049-9957