Entire cohort | Initial IFN HIGH | Initial IFN LOW | Univariate analysis | Multivariate analysis* | Stable IFN HIGH | Stable IFN LOW | Univariate analysis | Multivariate analysis* | |

Number of patients | 205 | 129 | 62 | 85 | 39 | ||||

Sex (M:F) | 18:187 | 9:120 | 8:54 | OR 0.50 (0.18 to 1.41) p=0.18 | 5:80 | 6:33 | OR 0.42 (0.12 to 1.42) p=0.16 | ||

Caucasian ethnicity (N (%)) | 84 (41.0) | 44 (34.1) | 33 (53.2) | OR 0.46 (0.24 to 0.85)p=0.013 | 18 (21.2) | 19 (48.7) | OR 0.28 (0.12 to 0.64)p=0.002 | ||

SE/NE Asian ethnicity (N (%)) | 81 (39.5) | 58 (45.0) | 16 (25.8) | OR 2.56 (1.33 to 5.10)p=0.006 | 49 (57.6) | 12 (30.8) | OR 3.47 (1.57 to 8.02)p=0.003 | ||

Southern/Central Asian ethnicity (N (%)) | 16 (7.8) | 11 (8.5) | 5 (8.1) | OR 1.07 (0.37 to 3.53) p=0.90 | 8 (9.4) | 4 (10.2) | OR 0.92 (0.27 to 3.63) p=0.90 | ||

Other/unknown ethnicity | 24 (11.7%) | 16 (12.4%) | 8 (12.9%) | OR 0.88 (0.34 to 2.47) p=0.81 | 10 (11.8%) | 4 (10.2%) | OR 1.05 (0.31 to 4.09) p=0.93 | ||

Age at study entry (years) (median (range)) | 43(18–84) | 40 (18–57) | 49 (20–84) | p=0.0002 | 38 (18–65) | 52 (20–77) | p<0.0001 | ||

Age of disease onset (years) (median (range)) | 28(7–77) | 27 (8–61) | 33 (7–77) | p=0.0008 | 27 (8–61) | 40 (13–69) | p=0.0001 | ||

Duration of disease (years) (median (range)) | 10 (0–49) | 11 (0–41) | 10 (0–49) | p=0.86 | 9 (0–41) | 10 (0–49) | p=0.51 | ||

Length of follow-up (days) (median (range)) | 637(42–789) | 658 (49–728) | 585 (42–747) | p=0.11 | 658 (63–789) | 602 (91–698) | p=0.52 | ||

Number of visits (median (range)) | 6 (1–28) | 7 (1–28) | 5 (1–17) | p<0.0001 | 8 (2–28) | 6 (2–18) | p=0.0009 | ||

Number of samples/patients (median (range)) | 3 (1–17) | 3 (1–17) | 2 (1–14) | p=0.06 | 4 (2–17) | 3 (2–14) | p=0.039 | ||

ANA positive (N (%)) | 200 (97.6) | 128 (99.2) | 58 (93.5) | OR 8.82 (1.00 to 174.7) p=0.05 | OR 5.02 (0.43 to 114.91) p=0.21 | 84 (98.9) | 37 (94.9) | OR2.21 (0.09 to 56.9) p=0.58 | OR 3.02 (0.09 to 91.53) 0.48 |

Speckled ANA (N (%)) | 111 (54.1) | 82 (63.6) | 22 (35.5) | OR 3.06 (1.62 to 5.89)p=0.0006 | OR 2.25 (1.20 to 4.42)p=0.02 | 54 (63.5) | 11 (28.2) | OR 4.41 (1.98 to 10.30)p=0.00039 | OR 3.06 (1.25 to 7.62)p=0.015 |

Homogeneous ANA (N (%)) | 85 (41.5) | 39 (30.2) | 40 (64.5) | OR 0.33 (0.17 to 0.63)p=0.001 | OR 0.33 (0.16 to 0.66)p=0.002 | 31 (36.5) | 27 (69.2) | OR 0.27 (0.11 to 0.61)p=0.002 | OR 0.29 (0.11 to 0.71)p=0.008 |

Nucleolar ANA (N (%)) | 33 (16.1) | 21 (16.3) | 10 (16.1) | OR 0.97 (0.43 to 2.30) p=0.94 | OR 0.87 (0.37 to 2.16) p=0.76 | 15 (17.6) | 6 (15.4) | OR 1.14 (0.42 to 3.45) p=0.80 | OR 0.99 (0.32 to 3.36) p=0.99 |

Other ANA (N (%)) | 14 (6.8) | 9 (7.0) | 5 (8.1) | OR 0.67 (0.23 to 2.10) p=0.48 | OR 0.62 (0.20 to 2.08) p=0.42 | 7 (8.2) | 3 (7.7) | OR 1.05 (0.27 to 5.08) p=0.95 | OR 1.51 (0.33 to 8.82) p=0.61 |

Anti-dsDNA† (N (%)) | 166/197 (83.8) | 108/124 (87.1) | 45/59 (76.3) | OR 2.1 (0.94 to 4.67) p=0.07 | OR 1.48 (0.61 to 3.52) p=0.38 | 75/84 (89.3) | 30/38 (78.9) | OR 2.22 (0.77 to 6.36) p=0.13 | OR 1.00 (0.27 to 3.45) p=0.99 |

Anti-RNP (N (%))† | 55/187 (29.4) | 44/122 (36.1) | 8/53 (15.1) | OR 3.17 (1.43 to 7.81)p=0.007 | OR 2.66 (1.16 to 6.72)p=0.03 | 30/83 (36.1) | 2/35 (5.7) | OR 9.34 (2.58 to 60.11)p=0.003 | OR 8.23 (2.11 to 55.30)p=0.008 |

Anti-Ro (N (%))† | 101/186 (53.3) | 79/121 (65.3) | 15/53 (28.3) | OR 4.77 (2.40 to 9.88)p<0.0001 | OR 4.24 (2.04 to 9.20)p=0.0001 | 51/82 (62.1) | 9/35 (25.7) | OR 4.75 (2.03 to 11.98)p=0.0005 | OR 3.89 (1.48 to 10.98)p=0.007 |

Anti-La (N (%))† | 42/185 (22.7) | 35/120 (29.2) | 6/53 (11.3) | OR 3.22 (1.34 to 9.01)p=0.014 | OR 3.48 (1.37 to 10.30)p=0.014 | 22/81 (27.2) | 2/35 (5.7) | OR 6.15 (1.66 to 39.92)p=0.018 | OR 5.15 (1.21 to 36.47)p=0.048 |

Anti-Sm (N (%))† | 34/185 (18.4) | 25/120 (20.8) | 7/53 (13.2) | OR 1.73 (0.73 to 4.60) p=0.24 | OR 1.42 (0.57 to 3.92) p=0.46 | 18/82 (22.0) | 3/35 (8.6) | OR 3.0 (0.93 to 13.47) p=0.10 | OR 2.28 (0.82 to 7.08) p=0.23 |

Bolded entries refer to results that are significant with p value <0.05.

*Multivariate analysis including variables of ethnicity and age.

†Data were unavailable for these variables for a small number of patients.

IFN, interferon; NE, North Eastern; SE, South Eastern.