Table 4

Baseline characteristics associated with incident CAC (among RA patients free of CAC at baseline)
Incident CAC: yes Incident CAC: no P-value IRR (95% CI) Adjusted IRRa (95% CI)
Demographics
  Age, years 59 ± 7 55 ± 6 0.03 1.06 (1.0, 1.14) NA
  Male; number (%) 5 (25%) 8 (15%) 0.32 1.65 (0.71, 3.84) 1.81 (0.79, 4.18)
  Caucasian race; number (%) 19 (95%) 44 (83%) 0.18 3.03 (0.45, 20.7) 2.58 (0.39, 17.3)
  Education; number (%) 16 (80%) 44 (83%) 0.76 0.86 (0.33, 2.21) 0.85 (0.32, 2.27)
    Some college or higher
Cardiovascular Risk Factors
  Diabetes; number (%) 1 (5%) 2 (4%) 0.81 1.14 (0.20, 6.46) 1.08 (0.21, 5.65)
  Hypertension (%) 11 (55%) 21 (40%) 0.24 1.56 (0.73, 3.33) 1.42 (0.67, 3.0)
    Systolic BP, mm Hg 129 ± 17 117 ± 15 0.01 1.03 (1.01, 1.05) 1.02 (1.0, 1.04)*
    Diastolic BP, mm Hg 76 ± 9 72 ± 8 0.09 1.03 (0.99, 1.09) 1.05 (1.01, 1.09)*
  Dyslipidemia (%)
    Total cholesterol, mg/dL 201 ± 29 192 ± 41 0.40 1.0 (0.99, 1.01) 1.0 (0.99, 1.01)
    LDL cholesterol, mg/dL 116 ± 20 112 ± 34 0.66 1.0 (0.99, 1.01) 1.0 (0.99, 1.01)
    HDL cholesterol, mg/dL 57 ± 16 61 ± 19 0.51 0.99 (0.97, 1.01) 0.98 (0.96, 1.01)
    Triglycerides, mg/dL 137 ± 86 97 ± 60 0.03 1.0004 (1.0, 1.01) 1.004 (1.0, 1.01)*
  Cigarette Smoking
    Current; number (%) 2 (10%) 4 (8%) 0.73 1.26 (0.36, 4.49) 0.97 (0.24, 3.94)
Serum inflammatory markers
  CRP, mg/L; median (IQR) 2.1 (0.5 to 9.6) 2.1 (0.8 to 5.2) 0.74 0.96 (0.72, 1.27) 0.99 (0.75, 1.32)
  IL-6, pg/mL; median (IQR) 4.0 (1.2 to 7.7) 2.3 (1.1 to 7.5) 0.45 1.12 (0.79, 1.58) 1.17 (0.83, 1.64)
  Fibrinogen, mg/dL; median (IQR) 362 (260 to 473) 338 (278 to 383) 0.89 1.08 (0.33, 3.50) 1.23 (0.39, 3.94)
  E-selectin, ng/mL; median (IQR) 49 (25 to 76) 45 (29 to 59) 0.90 1.0 (0.53, 1.88) 1.02 (0.58, 1.80)
  s-ICAM-1, ng/mL; median (IQR) 312 (247 to 383) 275 (225 to 322) 0.12 1.60 (0.58, 4.40) 1.31 (0.47, 3.62)
Disease characteristics at baseline
  Disease duration (years) 7 (4 to 14) 10 (5 to 20) 0.13 0.98 (0.94, 1.02) 0.97 (0.94, 1.01)
  DAS28 3.9 ± 0.9 3.7 ± 1.0 0.44 1.19 (0.81, 1.75) 1.20 (0.81, 1.78)
  HAQ 0.5 ± 0.7 0.5 ± 0.6 0.87 1.10 (0.60, 2.04) 1.12 (0.64, 1.95)
  Sharp score; median (IQR) 29 (15 to 73) 44 (11 to 90) 0.93 1.0 (0.99, 1.0) 1.0 (0.99, 1.0)
  Current use of MTX 10 (50%) 38 (72%) 0.08 0.52 (0.24, 1.09) 0.51 (0.25, 1.04)
  Current use of biologic agents 11 (55%) 24 (45%) 0.46 1.30 (0.61, 2.79) 1.29 (0.62, 2.68)
  Current use of corticosteroids 7 (35%) 19 (36%) 0.95 0.95 (0.43, 2.11) 1.02 (0.46, 2.26)
Disease characteristics, expressed as average over follow-up
  DAS28 3.5 ± 1.0 3.5 ± 1.0 0.90 1.04 (0.7, 1.6) 1.06 (0.7, 1.6)
  CRP, mg/L; median (IQR) 2.0 (0.9 to 6.5) 2.2 (1.2 to 6.2) 0.72 1.0 (1.0, 1.1) 1.0 (1.0, 1.1)
  IL-6, pg/mL; median (IQR) 4.7 (1.5 to 20.9) 3.7 (2.0 to 11.5) 0.87 1.0 (1.0, 1.2) 1.0 (1.0, 1.1)
  Fibrinogen, mg/dL; median (IQR) 358 (283 to 425) 361 (310 to 419) 0.78 1.0 (1.0, 1.0) 1.0 (1.0, 1.0)
  E-selectin, ng/mL; median (IQR) 44 (34 to 61) 43 (34 to 65) 0.78 1.0 (1.0, 1.0) 1.0 (1.0, 1.0)
  s-ICAM-1, ng/mL; median (IQR) 327 (242 to 367) 266 (240 to 323) 0.12 1.0 (1.0, 1.0) 1.0 (1.0, 1.0)

aAdjusted for age. *P <0.05. BP, blood pressure; CAC, coronary artery calcium; CRP, C-reactive protein; DAS28, disease activity score in 28 joints; HDL, high density lipoprotein; IQR, interquartile range; IRR, incidence rate ratio; LDL, low density lipoprotein; MTX, methotrexate; RA, rheumatoid arthritis; s-ICAM, soluble intercellular adhesion molecule.

Chung et al.

Chung et al. Arthritis Research & Therapy 2013 15:R134   doi:10.1186/ar4314

Open Data