Association of Autoimmune Thyroid Disease with Anti-GAD Antibody ELISA Test Positivity and Risk for Insulin Deficiency in Slowly Progressive Type 1 Diabetes

Table 2

Clinical characteristics of the patients based on GADA-RIA, GADA-ELISA, and AITD.

Group	T2D		SPT1D				value
	A0	A1	B0	B1	C0	C1
GADA-RIA	(−)	(−)	(+)	(+)	(+)	(+)
GADA-ELISA	(−)	(−)	(−)	(−)	(+)	(+)
AITD	(−)	(+)	(−)	(+)	(−)	(+)
	101	53	24	6	10	20
Age (years)	68 (60–75)	68 (64–75)	69 (61–75)	69 (61–72)	60 (50–68)	66 (53–69)	0.359
Gender (female/male)	41/60	29/24	6/18	2/4	4/6	13/7	0.066
BMI (kg/m^2)	23.8 (22.0–27.4)	23.8 (21.4–26.2)	23.1 (19.3–25.7)	24.4 (20.2–27.9)	23.8 (23.1–26.9)	24.0 (21.1–27.1)	0.726
HbA1c (%)	7.2 (6.7–7.6)	6.9 (6.5–7.6)	6.8 (6.4–7.5)	7.2 (6.6–9.2)	7.3 (6.8–8.2)	7.5 (6.8–8.3)	0.144
Age of onset of diabetes (years)	55 (44–61)	55 (48–65)	54 (44–66)	57 (53–63)	44 (34–53)	49 (43–54)	0.164
Duration of diabetes (years)	11.9 (6.0–17.4)	9.8 (4.9–16.0)	9.3 (5.3–17.9)	8.1 (7.0–9.3	11.4 (9.5–19.6)	12.5 (8.8–19.7)	0.677
Titer of GADA-RIA (U/mL)	—	—	4.5 (2.3–7.7)	5.7^† (4.4–6.4)	8.3^‡ (6.8–26.7)	74.0 †‡ (15.5–708.9)	<0.001
Titer of GADA-ELISA (U/mL)	—	—	—	—	38.3 (8.1–89.0)	317.0 (71.1–1354.9)	0.005
Insulin deficiency	1 (1.0)^§	0 (0.0)^§	1 (4.2)	2 (33.3)^§	7 (70.0)^§	9 (45.0)^§	<0.001
C-peptide undetected	0 (0.0)^§	0 (0.0)	1 (4.2)	0 (0.0)	3 (30.0)^§	4 (20.0)^§	<0.001
Glucose-lowering agents
Insulin	33 (32.7)^§	17 (32.1)	10 (41.7)	2 (33.3)	9 (90.0)^§	14 (70.0)^§	0.001
Insulin secretagogues	84 (83.2)^§	17 (32.1)	19 (79.2)	2 (33.3)^§	1 (10.0)^§	8 (40.0)^§	<0.001
Others (−/+)	71 (70.3)^§	30 (56.6)	11 (45.8)	5 (83.3)	3 (30.0)	7 (35.0)^§	0.005

Unless noted otherwise, data are shown as median (interquartile range), or number (%). , group B0 versus group C1; , group B1 versus group C1; , group C0 versus group C1; Absolute value of adjusted residual > 1.96. Insulin secretagogues include sulfonylureas, glinides, DPP-4 inhibitors, and GLP-1 receptor agonists. Others include biguanides, thiazolidines, α-glucosidase inhibitors, and SGLT2 inhibitors. T2D, type 2 diabetes; SPT1D, slowly progressive type 1 diabetes; GADA, anti-glutamic acid decarboxylase antibody; ELISA, enzyme-linked immunosorbent assay; BMI, body mass index; RIA, radioimmunoassay; AITD, autoimmune thyroid disease.