Table 3

Unadjusted associations of patient characteristics with the square root of the number of high titre anticitrullinated protein antibodies

Characteristicβ*p Value
Age, per year−0.00150.89
Male vs female0.3040.11
Caucasian vs other−0.4140.12
Any college vs less education−0.2980.17
Ever smoking vs never0.1350.47
Current smoking vs non-smoking0.7840.006
Reported lung disease vs none0.0130.96
BMI, per kg/m20.0120.51
RA duration, per year0.00670.44
RF seropositivity vs seronegative1.25<0.001
CCP2 seropositivity vs seronegative1.87<0.001
Any shared epitope alleles vs none0.4570.021
1 SE allele vs none0.4100.055
2 SE alleles vs none0.5450.028
Any *01 alleles0.0120.95
Any *04 alleles0.3070.095
Any *0401 alleles0.3930.040
Any *0404 alleles−0.0650.83
Any *10 alleles0.6060.15
Any *0401 or *10 alleles0.4840.009
DAS28-CRP, per unit−0.0140.87
CRP, per long unit0.1710.011
IL-6, per log unit0.272<0.001
Total SHS, per log unit0.1350.067
HAQ (0–3), per unit−0.1670.18
Rheumatoid nodules vs none0.903<0.001
Current prednisone0.3450.068
Cumulative prednisone, per gram0.00350.71
Current non-biologic DMARDs0.0350.89
Methotrexate0.3000.12
Leflunomide0.1750.57
Hydroxychloroquine−0.3100.15
Current biologic DMARDs0.1170.53
TNF inhibitors0.0480.80
  • *β coefficients represent the average change in the square root of the number of high level ACPA associated with a one unit higher value of the characteristic of interest from linear regression.

  • ACPA, anticitrullinated protein antibody; BMI, body mass index; CCP2, second generation commercial anticyclic citrullinated peptide assay; CRP, C reactive protein; DAS, Disease Activity Score; DMARD, disease modifying antirheumatic drug; HAQ, Health Assessment Questionnaire; IL, interleukin; RA, rheumatoid arthritis; RF, rheumatoid factor; SE, shared epitope; SHS, Sharp-van der Hiejde Score; TNF, tumour necrosis factor.