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Table 2 Comparison of characteristics between anti-CCP-positive non-RA CTD patients and RA-overlapping CTD patients

From: Long-term follow-up of patients with anti-cyclic citrullinated peptide antibody-positive connective tissue disease: a retrospective observational study including information on the HLA-DRB1 allele and citrullination dependency

  Non-RA
n = 31
RA-overlapping
n = 41
p value OR# (95% CI)
Age, median (IQR), years 59.0 (41.5–68.0) 64.0 (52.0–69.0) 0.30 ND
Women, % 87.1 92.7 0.45 1.86 (0.29–13.7)
Duration of CTD, median (IQR), years 10.0 (6.0–16.0) 14.0 (8.0–21.5) 0.25 ND
Arthritis 18 (58%) 41 (100%) 2.9 × 10−6 Inf (5.9 Inf)
Bone erosion 0/25 (0%) 29/41 (70.7%) 1.4 × 10−9 Inf (12.9 Inf)
RF(+ve/−ve) 18/10 (64%) 40/1 (98%) 3.1 × 10−4 21.2 (2.7–982)
Titer of aCCP, median (IQR), U/mL 29.4 (7.9–100) 72.6 (32.2–100) 0.045 ND
Negative conversion of aCCP 6/28 (21.4%) 5/36 (13.9%) 0.51 0.60 (0.13–2.7)
Usage of DMARDs 18 (58.1%) 37 (90.2%) 2.0 × 10−3 6.49 (1.69–31.3)
Usage of a medium dose of glucocorticoids 21 (67.7%) 18 (43.9%) 0.06 0.38 (0.12–1.09)
HLA-DRB1 SE§ 6/22 (27.2%) 20/32 (62.5%) 0.014 4.3 (1.20–17.5)
  1. CTD connective tissue disease, OR odds ratio, 95% CI 95% confidence interval, ND no data, Inf infinite, SD standard deviation, RF rheumatoid factor, aCCP anti-CCP antibody, DMARDs disease-modifying antirheumatic drugs, including methotrexate, bucillamine, salazosulfapyridine, tacrolimus, cyclosporine, mizoribine, etanercept, and tocilizumab, SE shared epitope
  2. #Calculated for categorical variables
  3. ≥ 100 U/mL was calculated as 100 U/mL
  4. ≥ 15 mg/day of a prednisolone equivalent
  5. §Assessed in 22 out of 31 patients in the non-RA group and 32 out of 41 patients in the RA-overlapping group