Assessment of anti-malondialdehyde-acetaldehyde antibody frequencies in rheumatoid arthritis with new data from two independent cohorts, meta-analysis, and meta-regression

Table 5 Characteristics of the studies reporting IgG anti-MAA antibody frequency in RA patients

Characteristics	Thiele, 2015 [4]^a	Mikuls, 2018 [18]	Mikuls, 2020 [8]	Petro, 2021 [23]	Grönwall, 2021 [6]	de Moel, 2023 [5] NLD/FNS/JPN/SA	Santiago	Barcelona
Number of patients	1720	284	214	1229	403	103/100/174/67	517	178
IgG anti-MAA⁺, %	92	80	22	67	44	29/29/22/53^b	6	7
European, %	78	75	58	89	100	100/0/0/0	100	100
African, %	16	17	Yes^c	6	0	0/0/0/100	0	0
Age, mean (SD)	63 (11)	59 (12)	37 (8)^d	57 (13)	50 (13)	58/48/60/49^e	61 (14)	59 (13)
Women, %	9	37	48	79	70	66/79/82/89	77	79
Ever smokers, %	80	62^f	33	52	72	60/84/28/12	20	46
Military, predominantly	Yes	Yes	Yes	No	No	No	No	No
anti-CCP⁺, %	78	85^f	71	55	69	100	64	71
IgG anti-MAA⁺/anti-CCP⁺, %	93	83	22^b	74	49	29/29/22/53^b	5	7
Percentile IgG anti-MAA^g	99	95	90	(67)^g	85	97.5^g	98	95
Years with RA, mean (SD)	12 (12)	13 (10)^f	7 (4)	-	1^h	1.3/7.7/7.5/0^e	14 (11)	6 (5)

^aStudies are referred to by the first author and publication year. de Moel (2023) [5] reports the frequency of IgG anti-MAA antibodies for four sets of patients: NLD, Dutch from the Netherlands; FNS, First Nations People from Canada; JPN, Japanese; SA, South Africans
^bIn these patient sets, we considered IgG anti-MAA⁺ % = IgG anti-MAA⁺/anti-CCP⁺ % for meta-regression because de Moel et al. (2023) [5] study included only anti-CCP⁺ RA patients and Mikuls et al. (2020) [8] did not report IgG anti-MAA⁺/anti-CCP⁺ %. We performed sensitivity analyses to check this procedure produced consistent results
^cAn unspecified fraction of the 42% non-EU patients have African ancestry. In meta-regression, we tested 32, 24, 16, and 8% with similar results (Supplementary Table 4) and reported the data for 8%
^dAge at diagnosis. The age used for meta-regression was 44 years resulting from adding the mean number of years with RA
^eMedian values in years
^fData obtained from (PMID: 24,782,175; https://0-doi-org.brum.beds.ac.uk/10.1002/art.38348)
^gPercentiles of anti-MAA antibodies used to define the threshold for positive anti-MAA antibody
^hAll patients in this collection have early RA (< 1 year)

ISSN: 1478-6362