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Table 2 Demographic Characteristics

From: Epidemiology and demographics of juvenile idiopathic arthritis in Africa and Middle East

Sr. No. Reference Country N (no. of cases) F:M Mean Age of onset (years) Subtype ANA positivity Uveitis RF positivity HLA-B27
Type No. % % Methodology of testing % Methodology/ Nature % Methodology of testing % Methodology of testing
Regional
1 Consolaro et al., 2019 [22] Africa and Middle East 1209 1.61 6·0 (2·9–9·8)* Psoriatic arthritis 37 3.1 NA NA 5.9 NM NA NA NA NA
RF-positive polyarthritis 61 5.0
Undifferentiated arthritis 68 5.6
ERA 111 9.2
Systemic 204 16.9
RF-negative polyarthritis 271 22.4
Oligoarticular 457 37.8
2 Al-Mayouf et al., 2021 [28] Arab (Saudi Arabia, Libya, United Arab Emirates, Jordan, Oman, Egypt, Kuwait) 702 2.04 5 (IQR 2.0- 9.0)* Undifferentiated 11 1.6 30.9 Immunoassay 8.3 NM 9.3 Immunoassay RF was tested at least twice, with a minimum of 3 months apart. Test results were interpreted according to cutoff values of the local laboratories. 5.3# Flow cytometry
Psoriatic 28 3.9
ERA 39 5.6
Oligoarticular Extended 43 6.1
Polyarticular RF positive 48 6.8
Polyarticular RF negative 159 22.6
Systemic 172 24.5
Oligoarticular persistent 202 28.8
Country
3 Khuffash et al., 1988 [13] Kuwait 41 1.28 NA Oligoarticular ANA negative 4 9.8 NA NM NA NA NA NA NA NA
Polyarticular seropositivity 5 12.2 NA
Oligoarticular ANA positive 5 12.2 12.2 60.0 Asymptomatic chronic uveitis detected by slit lamp examination by an ophthalmologist
Systemic polyarticular 6 14.6 NA NA NA
Systemic oligoarticular 10 24.4 NA
Polyarticular seronegative 11 26.8 NA
4 Khuffash et al., 1990 [14] Kuwait 108 1.04 NA Oligoarticular seropositive 3 2.8 NA NA NA NA NA NA NA NA
Oligoarticular ANA positive 9 8.3 8 NM
Polyarticular seropositive 10 9.3 NA NA
Systemic polyarticular 13 12.0
Systemic oligoarticular 18 16.7
Oligoarticular ANA negative 19 17.6
Polyarticular seronegative 36 33.3
5 Abdwani et al., 2015 [11] Oman 107 2.57 6.85 ± 3.86 years Psoriatic 1 0.9 32 Indirect Immunoflorescence; titer of ≥1:80 obtained on at least 1 clinic visit during the disease course was considered positive None Slit lamp examination by ophthalmologist during regular follow up visits at 3, 6 or 12 monthly intervals as per the pediatric screening recommendation 7.5 ELISA; RF was considered to be positive when titers were >20 IU/ml (If only one test of RF was performed, which was the case for many patients, then the results of this test were used to assign a JIA subtype rather than apply the subtype category of “other JIA.”) NA NA
ERA 3 2.8
Polyarticular RF positive 8 7.5
Systemic JIA 19 17.8
Oligoarticular JIA 34 31.8
Polyarticular RF negative 42 39.3
6 Ozen et al., 1998 [15] Turkey 30 0.67 NA Systemic 1 12.5 NA NA NA NA NA NA NA NA
Polyarticular 12 42.4
Oligoarticular 17 45.1
7 Abou El-Soud et al., 2013 [12] Egypt 132 1.59 12.5 ± 4.56 Systemic 18 13.6 48.5 Indirect immunofluorescence on Hep-2 cells, with positive titers from 1/40 with at least two determinations 3 months apart during the first 6 months of the disease 19.7 Detected by slit lamp examination 27.20 Semi-quantitative latex test; titers ≥30 IU/mL were considered positive with at least two determinations 3 months apart during the first 6 months of the disease 66 Low-resolution PCR analysis
ERA 6 4.5
Polyarticular RF positive 11 8.3
Polyarticular RF negative 28 21.2
Oligoarticular 69 52.3
8 Furia et al., 2020 [47] Tanzania 28 1.15 NA Oligoarticular 1 3.6 0.0 NM NA NA NA NA NA NA
Systemic 6 21.4
Polyarticular 21 75.0
9 Aiche et al., 2018 [31] Algeria 70 1.8 7.3* Psoriatic 1 1.4 2.9 NM 1.5 NM NA NA NA NA
Systemic 7 10.0
ERA 8 11.4
Polyarticular RF positive 14 20.0
Polyarticular RF negative 15 21.4
Oligoarticular 25 35.7
10 Al Marri et al., 2017 [32] Saudi Arabia 23 6.67 3.5 Psoriatic 1 4.3 8.7 NM NA NA 13.0 NM NA NA
Polyarticular RF positive 3 13.0
Polyarticular RF negative 5 21.7
Systemic 14 60.9
11 Al-Mayouf et al., 2018 [35] Saudi Arabia 100 1.70 4.5* ERA 3 3.0 15.0% NM 8.1% NM NA NA NA NA
Undifferentiated 3 3.0
Psoriatic 6 6.0
Polyarticular RF positive 13 13.0
Oligoarticular 23 23.0
Polyarticular RF negative 25 25.0
Systemic 27 27.0
12 Salah et al., 2009 [63] Egypt 196 1.09 6.257±3.41 years Systemic-onset 47 24.0 21.7 Indirect immunofluorescence; positive at serum dilution between 1:80 to 1:60 5.6 Slit lamp examination; all detected patients had chronic uveitis NA NA NA NA
Polyarthriticular 68 34.7
Extended oligoarticular 18 9.2
Persistent Oligoarticular 63 32.1
Oligoarticular 81  
13 Al-Abrawi et al., 2018 [33] Oman 57 2.35 5.9* ERA 0 0.0 7.0 NM 0 NM NA NA NA NA
Undifferentiated 0 0.0
Psoriatic 2 3.5
Polyarticular RF positive 6 10.5
Systemic 13 22.8
Oligoarticular 16 28.1
Polyarticular RF negative 20 35.1
14 Demirkaya et al., 2018 [45] Turkey 466 1.49 6.3 (2.7–10.8) Polyarticular RF positive 11 2.4 9.9 NM 8.1 NM NA NA NA NA
Undifferentiated 12 2.6
Psoriatic 15 3.2
Systemic 64 13.7
ERA 70 15.0
Polyarticular RF negative 105 22.5
Oligoarticular 189 40.6
15 El Miedany et al., 2018 [46] Egypt 100 0.89 9.2 (5.3–11)* Polyarticular RF positive 2 2.0 0.0 NM 6.0 NM NA NA NA NA
Psoriatic 2 2.0
ERA 2 2.0
Oligoarticular 10 10.0
Systemic 20 20.0
Polyarticular RF negative 24 24.0
Undifferentiated 40 40.0
16 Hashad et al., 2018 [48] Libya 100 2.33 6.4 (3.1-10.4)* Psoriatic 4 4.0 7.0 NM 2.0 NM NA NA NA NA
Polyarticular RF positive 5 5.0
Undifferentiated 5 5.0
ERA 13 13.0
Systemic 22 22.0
Polyarticular RF negative 25 25.0
Oligoarticular 26 26.0
17 Oyoo et al., 2016 [55] Kenya 68 2.4 8.45 ERA 4 5.9 10.9§ NM 1.47 Slit lamp examination by an ophthalmologist 17.6 One positive or negative RF assay was considered adequate to classify polyarticular patients NA NA
Systemic JIA 10 14.7
Polyarticular RF positive 12 17.6
Oligoarticular arthritis 16 23.5
Polyarticular RF negative 26 38.2
18 Scott et al., 2018 [57] South Africa 91 1.68 5.9* Systemic 4 4.4 2.2 NM 8.2 NM NA NA NA NA
Polyarticular RF positive 6 6.6
Psoriatic 6 6.6
Undifferentiated 8 8.8
ERA 14 15.4
Polyarticular RF negative 21 23.1
Oligoarticular 32 35.2
19 Sen et al., 2015 [58] Turkey 213 1.07 8.1 (range 8 months-15.4 years) Psoriatic 2 0.90 11.70 Immunofluorescent antibody method; titers >160 IU/mL were considered positive 4.20 Slit lamp examination by an ophthalmologist 13.10 Nephelometric method; positivity defined by titers >20 U/mL on at least two occasions during the first six months of disease onset 2.8^ PCR
Undifferentiated 0 0.00
Systemic 19 8.90
Polyarticular RF positive 23 10.80
ERA 23 10.80
Polyarticular RF negative 67 31.50
Oligoarticular 79 37.10
20 Shafaie et al., 2018 [59] Iran 102 2.19 5.2* ERA 0 0.0 2.9 NM 1.0 NM NA NA NA NA
Undifferentiated 0 0.0
Polyarticular RF positive 1 1.0
Psoriatic 1 1.0
Systemic 15 14.7
Polyarticular RF negative 16 15.7
Oligoarticular 69 67.6
21 Yener et al., 2020 [61] Turkey 116 1.58 NA Undifferentiated 0 0.0 44** Immunofluorescence; titer of 1/100 was considered positive 2.6 Slit lamp examination by an ophthalmologist every 6 months 22.7## Two RF values above 10 U/L measured at an interval of 3 months in a 6-month period were considered significant 21.1†† Positive or negative for antigen
Psoriatic 4 3.4
Systemic 15 12.9
Polyarticular RF positive 5 4.3
Polyarticular RF negative 17 14.7
Oligoarticular 37 31.9
ERA 38 32.8
22 Çakan et al., 2017 [41] Turkey 265 0.95 NA Undifferentiated 5 1.9 27.20 Indirect Immunofluorescence; titers ≥1:100 were classified as positive 4.5 All cases were of anterior uveitis 3.8 Verified by a second analysis at least 3 months later 26‡‡ NM
Psoriatic JIA 5 1.9
Polyarticular RF positive 10 3.8
Systemic JIA 35 13.2
Persistent oligoarticular 81 30.6
Polyarticular RF negative 36 13.5
Extended Oligoarticular JIA 6 2.3
ERA 87 32.9
23 Kasapçopur et al., 2004 [51] Turkey 198 0.87 6.62 ± 4.12 Other 5 2.5 18.2 Hep-2 cell; titers above 1/40 were considered positive 10.1 Slit lamp and a detailed ophthalmologic examination by ophthalmologist; single evaluation was considered sufficient for uveitis positivity; repeated every 3 months in uveitis and ANA positive patients 3.5 Nephlometric method NM Histocompatibility antigen determination
Polyarticular RF positive 7 3.5
Extended Oligoarticular 9 4.5
Psoriatic JIA 11 5.6
Polyarticular RF negative 34 17.2
Oligoarticular JIA 37 18.7
ERA 43 21.7
Systemic JIA 52 26.3
24 Ozdogan et al., 1991 [56] Turkey 147 0.77 8.4±3.9 Juvenile spondylitis 3 2.0 5.6 Indirect Immunofluorescence using human leukocytes as nuclear substrate and fluorescein anti IgG antisera 7.5 Slit lamp examination; Chronic uveitis in 7 patients and acute anterior uveitis in 1 male patient 10 Latex slide agglutination test 45 Standard microcytotoxicity test
Polyarticular sero-positive 7 5.0
Polyarticular sero-negative 19 13.0
Systemic 37 25.0
Pauciarticular 81 55.0
25 Abdul-Sattar et al., 2014 [30] Egypt 52 2.06 NA Polyarticular RF positive 5 10.0 NA NA NA NA NA NA NA NA
Oligoarticular persistent 9 17.0
Polyarticular RF negative 11 21.0
Systemic 12 23.0
Oligoarticular extended 15 29.0
26 Abdul-Sattar et al., 2014 [29] Egypt 58 2.41 NA Polyarticular RF positive 5 8.6 NA NA NA NA NA NA NA NA
Oligoarticular persistent 11 19.0
Polyarticular RF negative 12 20.7
Systemic 13 22.4
Oligoarticular extended 17 29.3
27 Albokhari et al., 2019 [36] Saudi Arabia 44 1.59 NA ERA 0 0.0 NA NA NA NA NA NA NA NA
Psoriatic 2 4.5
Oligoarticular 6 13.6
Polyarticular 7 15.9
Systemic 12 27.3
Unknown 17 38.6
28 Al-Hemairi et al., 2015 [34] Saudi Arabia 82 1.65 7.1 ± 3.6 year Undifferentiated 0 0.0 36.58 ELISA; titer of 1:80 or more was considered positive. Positivity was confirmed only if two samples were positive at least three months apart 8.53 Slit lamp examination by an ophthalmologist 4.87§§ RF positivity was confirmed only if two samples were positive, tested three months apart 100% in ERA NM
ERA 1 1.2
Polyarticular RF positive 4 4.9
Psoriatic 4 4.9
Polyarticular RF negative 20 24.4
Oligoarticular 23 28.0
Systemic 30 36.6
29 Amine et al., 2009 [38] Morocco 80 1.42 7.53 Extended oligoarticular 4 5.0 NA NA NA NA NA NA NA NA
Systemic 21 26.0
Polyarticular 25 31.5
Persistent oligoarticular 30 37.5
30 Bahabari et al., 1997 [39] Saudi Arabia 115 1.21 6(0.75-16) ERA 0 0.0 30.0 Indirect immunofluorescence; positive at serum dilution between 1:80 to 1:60 1.70 Chronic uveitis 10.0 Slide agglutination test (till 1991); ELISA (after 1992) 6.0 ¶¶ Standard microcytotoxicity
Polyarticular RF positive 12 10.4
Polyarticular RF negative 23 20.0
Oligoarticular 30 26.1
Systemic 50 43.5
31 Bouaddi et al., 2013 [40] Morocco 33 0.83 NA Polyarticular RF negative 1 3.0 76 NM NA NA 12.10 NM NA NA
Oligoarticular 4 12.1
ERA 5 15.2
Systemic 8 24.2
Polyarticular RF positive 15 45.5
32 Chipeta et al., 2013 [42] Zambia 78 1.23 8.70 years (range: 1–15 years) Psoriatic 1 1.3 NA NA 11.50 Chronic uveitis in 3 patients with oligoarticular JIA and in 2 patients with ERA; Acute uveitis in 1 each of ERA and polyarticular JIA NA NA NA NA
ERA 5 6.4
Polyarticular RF positive 9 11.5
Systemic 11 14.1
Oligoarticular 25 32.1
Polyarticular RF negative 27 34.6
33 Hussein et al., 2018 [49] Egypt 63 0.90 6.1 (range 3-14) ±2.8 ERA 0 0.0 20.6 NM 6.3 Slit lamp examination 69.8 NM NA NA
Undifferentiated 0 0.0
Psoriatic Arthritis 0 0.0
Polyarticular RF negative 6 9.5
Systemic 15 23.8
Polyarticular RF positive 16 25.4
Oligoarticular 26 41.3
34 Olaosebikan et al., 2017 [54] Nigeria 28 NA NA Systemic 5 17.9 NA NA NA NA 7.14^^ Nephlometry NA NA
Oligoarticular 9 32.1
Polyarticular 14 50.0
35 Weakley et al., 2012 [60] South Africa 78 1 8 (4–10)* Psoriatic Arthritis 1 1.3 3.8*** Majority ELISA, remaining Hep 2 immunofluorescent NA NA 14.1^^^ One positive or negative assay for RF was considered sufficient to classify a patient with polyarthritis 23### NM
Oligoarticular Extended 4 5.1
Systemic 6 7.7
Polyarticular RF positive 11 14.1
Persistent Oligoarticular 17 21.9
ERA 18 23.0
Polyarticular RF negative 21 26.9
36 Mostafa et al., 2019 [53] Egypt 48 2.42 NA Psoriatic 0 0.0 NA NA NA NA 42.0 NM NA NA
ERA 0 0.0
Oligoarticular 8 17.0
Polyarthritis 28 58.0
Systemic 12 25.0
37 Dagher et al., 2014 [43] Lebanon 66 1 5.2 years (range: 9 months - 14 years). Polyarticular RF positive 0 0.0 23 NM 6.1 NM NA NA NA NA
Oligoarticular extended 3 4.0
Undifferentiated 3 5.0
ERA 11 17.0
Systemic 15 23.0
Polyarticular RF negative 16 24.0
Oligoarticular persistent 18 27.0
38 Khawaja et al., 2017 [52] UAE 66 2.47 NA ERA 1 1.5 NA NA 7.6 NM NA NA NA NA
Psoriatic 1 1.5
Oligoarticular extended 3 4.5
Polyarticular RF positive 12 18.2
Systemic 13 19.7
Oligoarticular persistent 16 24.2
Polyarticular RF negative 20 30.3
39 Alzyoud et al., 2020 [37] Jordan 210 1.23 5.08±3.4 (7 months to 14 years) Polyarticular RF positive 8 3.8 33.60 Indirect immunofluorescence using Hep-2 cells; titers > 1/80 were considered positive 14.2††† Slit lamp examination at a dedicated uveitis clinic 3.80 Nephelometry; Considered positive when titers were ≥ 15 units/mL. and at least two positive results, 3 months apart, in the first 6 months of observation NA NA
ERA 15 7.1
Polyarticular RF negative 18 8.5
Psoriatic arthritis 18 8.5
Systemic arthritis 36 17.1
Persistent Oligoarticular 96  
Extended Oligoarticular 19  
Oligoarticular 115 54.7
40 Demirkaya et al., 2011 [44] Turkey 634 1.26 7.69±4.41 (1-11 years) Psoriatic 13 2.1 30.1 Titer of 1:80 was chosen as a cut-off point for ANA positivity for at least two positive results at least 3 months apart 11.6 Defined in accordance with the criteria of the SUN Working Group^^^^ 3.1‡‡‡ NM 63.3§§§ NM
RF positive polyarthritis 20 3.2
Extended Oligoarticular 26 4.1
Systemic 92 14.5
ERA 120 18.9
RF negative polyarthritis 129 20.3
Persistent Oligoarticular 234 36.9
41 Karadag et al., 2020 [50] Turkey 281 NA NA RF positive polyarticular 4 1.4 NA NA NA NA NA NA NA NA
Undifferentiated 7 2.5
Systemic 11 3.9
Psoriatic 13 4.6
RF negative polyarticular 19 6.8
ERA 97 34.5
Oligoarticular 130 46.3
42 Yilmaz et al., 2008 [62] Turkey 196 0.92 6.9 ± 3.7 Psoriatic arthritis 2 1.0 14.2 Indirect Immunofluorescence using Hep-2 cell; titers >1/80 were considered positive 2 Slit lamp and detailed ophthalmological examination by ophthalmologist every 4 – 6 months; chronic uveitis occurred in 2 patients with persistent oligoarticular JIA 8.1 Nephelometry; Considered positive when titers were 15 units/mL and confirmed with two positive results, 3 months apart, during the first 6 months of observation 5.6 Lymphocytotoxicity assay
Others 5 2.5
RF (+) polyarticular JIA 13 6.6
Oligoarticular Extended 19 9.6
ERA 19 10.3
Systemic JIA 30 15.0
Oligoarticular Persistent 48 24.4
RF (–) polyarticular JIA 60 30.6
  1. * Represents values in median
  2. #All patients underwent HLA-B27 testing; number patients tested not available in the article
  3. 3 out of 5 oligoarticular JIA patients tested positive for uveitis, however no full cohort uveitis rate is mentioned
  4. HLA testing was carried out in only ERA (6 cases)
  5. §Not all cases were tested (5/46; 2 oligoarticular, 3 polyarticular RF Positive)
  6. Only in RF positive patients
  7. ^Note that HLA-B27 test was done in only 47 of the 213 JIA patients
  8. **overall (62.22% in oligo)
  9. ##In polyarticular JIA
  10. ††in ERA
  11. ‡‡HLA-B27 was studied in 169 patients (in all patients with ERA phenotype and male patients over the 6 years of age)
  12. §§Note that only the RF positive polyarticular patients tested positive (n=82)
  13. ¶¶HLA-B27 was tested in 32 patients
  14. ^^Positive in 2 polyarticular positive RF and this is not specific to JIA patients only
  15. ***ANA testing was performed only on oligoathritis patients(n=67)
  16. ^^^Performed for polyarticular subtype
  17. ###HLA tests were only performed for ERA subtype; all patients tested positive
  18. †††Most of them were Oligoarticular JIA 25/115 (21.7%) and were associated with positive ANA in 16/115 (14%)
  19. ‡‡‡Tested in all except systemic; positive in only RF positive cases
  20. §§§Tested only in ERA patients
  21. ¶¶¶In patients with uveitis; 24.6% in patients without uveitis; 28.4% combined population
  22. ^^^^Both the publications have cited Jabs et al., 2005 for the SUN Working Group Anatomic Classification of Uveitis. SUN working group has classified uveitis based on the primary site of inflammation: anterior uveitis (anterior chamber); intermediate uveitis (vitreous); posterior uveitis (retina or choroid); panuveitis (anterior chamber, vitreous, and retina or choroid).
  23. ANA, anti-nuclear antibody; ARA, American Rheumatology Association; ELISA, Enzyme-Linked Immunoassay; ERA, enthesitis-related arthritis; EULAR, The European League Against Rheumatism; HLA, human leukocyte antigen; ILAR, International League of Associations for Rheumatology; IQR, interquartile range; JIA, juvenile idiopathic arthritis; NA, not available (study did not assess the parameter); NM, not mentioned; PCR, polymerase chain reaction; RF, rheumatoid factor.