Table 3

Associations between rheumatoid factor and anti-CCP antibodies with insulin resistance alone and in combination with one another after serial adjustment

Variable

Numbers of patients

Association with HOMA-IR

TRF & IP risk factor adjusted IR

β-Coefficient OR (95% CI) ^#

RF +ve *

90 (47%)

0.867 (0.204, 1.530)

ACPA +ve *

66 (35%)

1.423 (0.701, 2.146)

RF-ve/ACPA -ve

96 (49%)

0

RF +ve/

ACPA -ve ^†

29 (15%)

-0.015 (-0.973, 0.944)

ACPA+ve/

RF -ve^†

6 (3%)

0.932 (-0.898, 2.763)

Both RF+ve/ACPA+ve ^†

60 (31%)

1.472 (0.695, 2.250) ^√

* = Seropositive vs. seronegative for RF and ACPA (n = 193 and 191, respectively)

† = Patients stratified into four groups depending on autoantibody status and compared with other groups (n = 191)

√ = Model significantly different in patients positive for both RF and ACPA relative to those RF positive only (P = 0.0061) with age and gender and other parameters adjusted.)

^▲Linear regression producing β-coefficients were used for continuous outcome. β-coefficients are considered statistically significant if their 95% CI values do not include zero.

^#Logistic regression producing odds ratios used for binary outcomes. Odds ratios are considered significant if the 95% CI values do not include 1.

ACPA, anti-CCP antibody; IP, inflammatory polyarthritis; RF, rheumatoid factor.

Mirjafari et al. Arthritis Research & Therapy 2011 13:R159   doi:10.1186/ar3476