Table 2.

Subgroup analysis.

			Effect size			Heterogeneity
Subgroup	Class	Study	RR	95%CI	p	Q	I2	τ2
SLE	Overall	7	1.43	1.19-1.73	<0.001	16.84	64.38	0.03
	< 65 year	2	1.93	0.31-11.75	0.47	5.29	81.10	1.40
	> 65 year	2	1.23	0.96-1.56	0.09	0.87	0	0
	Male	1	1.36	1.04-1.75	0.05	–	–	–
	Female	1	1.47	1.32-1.64	0.05	–	–	–
	AD	2	1.37	0.60-3.14	0.45	4.40	77.29	0.28
	VaD	2	2.29	0.93-5.63	0.06	2.52	60.40	0.29
SS	Overall	8	1.26	1.14-1.39	<0.001	18.11	61.36	0.01
	< 65 year	1	1.57	1.24-1.98	0.05	–	–	–
	> 65 year	1	1.45	1.30-1.63	0.05	–	–	–
	Male	2	1.24	1.06-.1.45	0.005	0.44	0	0
	Female	1	1.11	1.02-1.22	0.05	–	–	–
RA	Overall	10	0.98	0.90-1.07	0.74	96.30	89.61	0.01
	< 65 year	3	0.87	0.60-1.27	0.48	12.55	76.09	0.10
	> 65 year	3	0.79	0.54-1.14	0.21	60.91	95.07	0.13
	Male	4	0.77	0.51-1.17	0.22	43.98	90.90	0.18
	Female	4	0.86	0.67-1.10	0.23	44.34	90.98	0.06

RA, Rheumatoid arthritis; SS, Sjogren’s syndrome; SLE, Systemic lupus erythematosus; AD, Alzheimer’s disease; VaD, Vascular dementia.