Table 1 Baseline clinical characteristics of Juvenile Idiopathic Arthritis (JIA) patients enrolled in PAFLAR registry from 15^TH April 2000–5th December 2023

Gender, n (%)

 Female

177 (58.6)

15 (68.2)

32 (57.1)

95 (62.9)

3 (42.9)

32 (48.5)

Ethnicity, n (%)

 Arab African

233 (77.9)

21 (100.0)

0 (0.0)

147 (98.7)

0 (0.0)

65 (98.5)

 White

4 (1.3)

0 (0.0)

4 (7.1)

0 (0.0)

0 (0.0)

0 (0.0)

 Black African

61 (20.4)

0 (0.0)

52 (92.9)

1 (0.7)

7 (100.0)

1 (1.5)

 Mixed Race

1 (0.3)

0 (0.0)

0 (0.0)

1 (0.7)

0 (0.0)

0 (0.0)

Age in years, Median (IQR)

14.0 (9.0–18.0)

9.5 (7.2–12.8)

12.0 (9.0–14.0)

16.0 (11.0–19.0)

15.0 (10.0–17.0)

13.0 (10.0–17.0)

Age at onset (years), Median (IQR)

7.0 (3.0–11.0)

5.0 (4.0–7.0)

7.5 (4.0–11.0)

6.0 (3.0–10.0)

10.0 (6.5–11.5)

9.0 (5.0–12.0)

Age at diagnosis (years), Median (IQR)

8.5 (5.0–12.0)

5.0 (4.0–7.0)

9.0 (6.0–12.5)

8.0 (5.0–11.0)

12.0 (9.5–16.0)

10.0 (6.0–14.0)

Time to diagnosis (Months), Median (IQR)

6.0 (1.0–20.8)

0.5 (0.0–3.8)

11.0 (1.3–33.5)

6.0 (1.0–15.8)

21.0 (9.0–30.0)

9.0 (1.0–30.0)

JIA Categories, n (%)

Oligoarthritis

58 (19.2)

6 (27.3)

2 (3.6)

31 (20.5)

1 (14.3)

18 (27.3)

 Oligo-persistent arthritis

22 (7.3)

1 (4.5)

10 (17.9)

10 (6.6)

0 (0.0)

1 (1.5)

 Oligo-extended arthritis

6 (2.0)

0 (0.0)

0 (0.0)

5 (3.3)

0 (0.0)

1 (1.5)

Polyarthritis RF-

54 (17.9)

0 (0.0)

11 (19.6)

34 (22.5)

3 (42.9)

6 (9.1)

Enthesitis-related arthritis

55 (18.2)

0 (0.0)

8 (14.3)

20 (13.2)

0 (0.0)

27 (40.9)

Psoriatic arthritis

21 (7.0)

1 (4.5)

0 (0.0)

16 (10.6)

0 (0.0)

4 (6.1)

Systemic onset arthritis

57 (18.9)

14 (63.6)

11 (19.6)

26 (17.2)

2 (28.6)

4 (6.1)

Polyarthritis RF+

15 (5.0)

0 (0.0)

6 (10.7)

6 (4.0)

1 (14.3)

2 (3.0)

Undifferentiated

17 (5.6)

0 (0.0)

8 (14.3)

5 (3.3)

0 (0.0)

4 (6.1)

Clinical Features, n (%)

 Fever

85 (28.1)

14 (63.6)

23 (41.1)

36 (23.8)

2 (28.6)

10 (15.2)

 Hepatomegaly

11 (3.6)

4 (18.2)

3 (5.4)

3 (2.0)

1 (14.3)

0 (0.0)

 Rash

47 (15.6)

8 (36.4)

6 (10.7)

30 (19.9)

0 (0.0)

3 (4.5)

 Splenomegaly

5 (1.7)

3 (13.6)

0 (0.0)

1 (0.7)

0 (0.0)

1 (1.5)

 Anemia

29 (9.6)

9 (40.9)

2 (3.6)

8 (5.3)

1 (14.3)

9 (13.6)

 Lymphadenopathy

24 (7.9)

7 (31.8)

3 (5.4)

11 (7.3)

1 (14.3)

2 (3.0)

 Serositis

5 (1.7)

5 (22.7)

0 (0.0)

0 (0.0)

0 (0.0)

0 (0.0)

 Psoriasis

5 (1.7)

1 (4.5)

0 (0.0)

1 (0.7)

0 (0.0)

3 (4.5)

 Nail pits

2 (0.7)

0 (0.0)

0 (0.0)

2 (1.3)

0 (0.0)

0 (0.0)

 Other

22 (7.3)

0 (0.0)

10 (17.9)

11 (7.3)

0 (0.0)

1 (1.5)

Physical exam findings, n (%)

 Tender joint

241 (80.9)

22 (100.0)

39 (70.9)

118 (79.2)

7 (100.0)

55 (84.6)

 Swollen joint

204 (68.7)

21 (95.5)

31 (56.4)

111 (74.5)

6 (85.7)

35 (54.7)

 Enthesitis

35 (13.1)

1 (6.2)

1 (2.3)

19 (13.3)

0 (0.0)

14 (24.1)

 Joint with limited range of motion

174 (58.4)

8 (36.4)

33 (60.0)

101 (67.8)

6 (85.7)

26 (40.0)

 Dactylitis

9 (4.4)

1 (7.1)

2 (25.0)

3 (2.8)

3 (42.9)

0 (0.0)

 Uveitis

  Acute

4 (6.5)

0 (0.0)

2 (66.7)

1 (6.7)

0 (0.0)

1 (2.6)

  Chronic

15 (24.2)

1 (33.3)

1 (33.3)

9 (60.0)

0 (0.0)

4 (10.5)

 None

43 (69.4)

2 (66.7)

0 (0.0)

5 (33.3)

3 (100.0)

33 (86.8)

Baseline Investigations

ESR (n = 246), Median (IQR)

35.0 (15.0–60.0)

40.0 (30.0–60.0)

35.0 (20.0–64.0)

35.0 (14.0–59.0)

99.0 (41.5–122.0)

25.0 (13.0–54.8)

CRP (n = 169), Median (IQR)

13.0 (3.0–52.4)

12.0 (10.0–24.0)

22.0 (8.1–76.0)

15.5 (2.0–62.0)

232.2 (200.0–272.4)

5.9 (2.8–38.3)

Hb levels (n = 257), Median (IQR)

11.2 (10.0–12.3)

9.8 (9.0–10.3)

10.4 (9.5–12.4)

11.2 (10.0–12.3)

9.7 (8.2–10.8)

12.0 (11.0–12.6)

Serology ANA, n (%)

Present

66 (22.4)

6 (27.3)

10 (19.2)

36 (24.0)

1 (14.3)

13 (20.3)

Absent

171 (58.0)

16 (72.7)

13 (25.0)

94 (62.7)

6 (85.7)

42 (65.6)

Not done

58 (19.7)

0 (0.0)

29 (55.8)

20 (13.3)

0 (0.0)

9 (14.1)

Serology RF, n (%)

Present

23 (8.0)

0 (0.0)

4 (8.2)

13 (8.7)

1 (14.3)

5 (8.2)

Absent

195 (67.7)

22 (100.0)

15 (30.6)

112 (75.2)

5 (71.4)

41 (67.2)

Not done

70 (24.3)

0 (0.0)

30 (61.2)

24 (16.1)

1 (14.3)

15 (24.6)

Serology HLA B27, n (%)

Present

14 (5.1)

0 (0.0)

2 (5.6)

8 (5.3)

0 (0.0)

4 (6.7)

Absent

103 (37.9)

10 (52.6)

2 (5.6)

63 (42.0)

2 (28.6)

26 (43.3)

Not done

155 (57.0)

9 (47.4)

32 (88.9)

79 (52.7)

5 (71.4)

30 (50.0)

Serology anti CCP, n (%)

Present

11 (4.2)

0 (0.0)

3 (7.3)

6 (4.0)

1 (14.3)

1 (1.8)

Absent

72 (27.2)

6 (50.0)

5 (12.2)

26 (17.3)

2 (28.6)

33 (60.0)

Not Done

182 (68.7)

6 (50.0)

33 (80.5)

118 (78.7)

4 (57.1)

21 (38.2)

CHAQ (n = 28), Median (IQR)

1.3 (0.7–2.0)

1.3 (1.0–1.7)

6.0 (6.0–6.0)

NA (NA – NA)

NA (NA – NA)

0.2 (0.0–2.5)

JADAS 10 score (n = 105), Median (IQR)

10.3 (4.8–18.2)

13.0 (8.9–19.5)

26.0 (17.8–31.0)

3.0 (3.0–3.2)

6.0 (5.5–8.5)

10.2 (5.0–16.0)

Medication at Diagnosis

bDMARD + NSAID

3 (1.7)

0 (0.0)

1 (4.0)

0 (0.0)

0 (0.0)

2 (3.5)

csDMARD only

32 (18.1)

10 (58.8)

4 (16.0)

12 (16.4)

0 (0.0)

6 (10.5)

csDMARD + bDMARD

5 (2.8)

2 (11.8)

1 (4.0)

1 (1.4)

0 (0.0)

1 (1.8)

csDMARD + bDMARD + NSAID

2 (1.1)

0 (0.0)

0 (0.0)

0 (0.0)

0 (0.0)

2 (3.5)

csDMARD + bDMARD + Steroid

4 (2.3)

1 (5.9)

0 (0.0)

0 (0.0)

0 (0.0)

3 (5.3)

csDMARD + NSAID

31 (17.5)

0 (0.0)

4 (16.0)

8 (11.0)

0 (0.0)

19 (33.3)

csDMARD + Steroid

9 (5.1)

3 (17.6)

3 (12.0)

2 (2.7)

0 (0.0)

1 (1.8)

csDMARD + Steroid + NSAID

9 (5.1)

0 (0.0)

0 (0.0)

9 (12.3)

0 (0.0)

0 (0.0)

NSAID only

55 (31.1)

0 (0.0)

6 (24.0)

29 (39.7)

0 (0.0)

20 (35.1)

Steroid only

17 (9.6)

0 (0.0)

4 (16.0)

8 (11.0)

5 (100.0)

0 (0.0)

Steroid + NSAID

6 (3.4)

0 (0.0)

1 (4.0)

4 (5.5)

0 (0.0)

1 (1.8)