Table 2 Clinical characteristics of patients with pSS-EGM and pSS-non-EGM.

Characteristics	pSS-EGM	pSS-non-EGM	P value
Number	122	29
Gender (Female/male)	116/6	29/0	0.490
Age	52.9 ± 13.9	49.6 ± 12.5	0.247
Disease duration	5.4 ± 5.6	3.9 ± 2.9	0.176
GDF15, pg/mL	1330 (885–2620)	986.2 (736.9–1274)	0.004**
Total protein, g/L	71.6 (66.9–79.4)	76.2 (71.8–80.6)	0.049*
Albumin, g/L	39.8 (35.6–43.5)	44.8 (42.2–46.6)	< 0.001***
Globulin, g/L	31.6 (28.3–36.6)	32.1 (26.5–34.2)	0.948
Albumin/Glbumin	1.2 (1–1.4)	1.4 (1.3–1.6)	< 0.001***
C-reactive protein, mg/L	3.1 (1.9–7.5)	1.7 (1.3–1.9)	< 0.001***
Erythrocyte sedimentation rate, mm/h	59 (31.2–95.5)	33 (19–66.5)	0.016*
Rheumatoid factor, IU/ ml	28.9 (20–101)	31.4 (20–93.4)	0.733
Complement fractions 4, mg/L	196 (148–235)	177 (147–208)	0.309
Complement fractions 3, mg/L	831.5 (693–964.5)	815 (736–895)	0.838
Immunoglobulins G, g/L	16.7 (13.4–21.6)	15.5 (13.4–19.9)	0.418
Immunoglobulins A, mg/L	3161 (2394–4020)	2950 (2400–3890)	0.994
Immunoglobulins M, mg/L	1240 (847–1732)	1080 (893–1370)	0.608
White blood cell count, × 10⁹/L	5.7 (4.6–7.3)	5.1 (3.9–5.4)	0.009**
Neutrophil count, × 10⁹/L	3.6 (2.5–5.3)	2.6 (2–3.3)	0.006**
Red blood cell count, × 10¹²/L	4.1 (3.7–4.4)	4.3 (4.1–4.5)	0.053
Haemoglobin, g/L	121 (108–131)	130 (122–136)	0.003**
Platelet count, × 10⁹/L	211 (153.5–263)	191 (174–212.5)	0.711
Positivity of anti-SSA (%)	88.7	96.0	0.466
Positivity of anti-SSB (%)	45.3	52.0	0.545
Antinuclear antibody positive (%)	87.7	89.7	1.0
Dry mouth, n (%)	65 (53.3)	16 (55.2)	0.854
Dry eyes, n (%)	40 (32.8)	8 (27.6)	0.589

Data are presented as number of patients, mean ± standard deviation or median (interquartile range). pSS-EGM, primary Sjögren’s syndrome patients with extra-glandular manifestations; pSS-non-EGM, primary Sjögren’s syndrome patients without extra-glandular manifestations; GDF15, Growth differentiation factor 15; Statistical signifcance is indicated by asterisks (* p < 0.05, ** p < 0.01, *** p < 0.001).

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