Table 3

Association of risk factors and disease characteristics with the DI

Independent variableβ (95% CI) (RA-patients (n=56), controls (n=50))β (95% CI) (RA-patient only (n=140))β (95% CI) (RA-patient only (n=140))
Three multivariate regression analysis models with DI as dependent variable
 RA−GC*−42489 (−96745 to 11767)
 RA+GC*−23040 (−75891 to 29810)
 Waist circumference−1778 (−4895 to 1338)315 (−1831 to 2462)274 (−2009 to 2557)
Age−3295 (−5219 to −1370)−1280 (−2502 to −57)−1100 (−2385 to 186)
 BMI6205 (−1930 to 14340)−2771 (−8193 to 2650)−3070 (−8893 to 2752)
 Female gender−8287 (−52574 to 36000)25773 (−10358 to 61904)31014 (−6984 to 69013)
 Cumulative GC dose (mg)−482 (−1307 to 343)−284 (−1150 to 582)
 Daily GC dose−885 (−4669 to 2899)140 (−3731 to 4010)
 DAS28−4759 (−16525 to 7007)
 Any erosions of the hands or feet−14480 (−50730 to 21770)
 Past DMARDs (n)§662 (−7572 to 8896)
 ACPA24336 (−9300 to 57973)
 Disease duration (years)−1392 (−3447 to 664)
  • Three multivariate models, correcting for age, BMI and female gender were used to test associations with the β-cell parameter DI: (1) tested RA populations (as compared with healthy controls), (2) tested cumulative and daily GC dose and (3) tested disease activity (DAS28 and its components, DMARD use, hand or feet erosions on x-ray, ACPA).

  • Significant associations (p<0.05) are depicted in bold

  • * RA−GC and RA+GC populations are tested against the control subject population; only patients with RA with normal glucose tolerance during OGTT and without first-degree relatives with type 2 diabetes mellitus were included for the comparison with control subjects. RA+GC was significantly associated with DI when these analyses were performed with log-transformed DI.

  • Cumulative GC dose, daily GC dose were separately tested in models of the RA population only.

  • Disease parameters (DAS28, DAS28-CRP, CRP, ESR) were separately tested in the model of the RA population only; only DAS28 and significant correlations are depicted.

  • § Number of DMARDs (both synthetic and biological; not GCs) that were used by a patient in the past.

  • ACPA, anti-citrullinated protein antibodies; BMI, body mass index; CRP, C-reactive protein; DAS28, Disease Activation Score measured by questioning general health, physical examination of 28 joints and ESR or CRP; DI, Disposition Index; DMARD, disease-modifying antirheumatic drug; ESR, erythrocyte sedimentation rate; GC, glucocorticoid; RA, rheumatoid arthritis; RA+GCs, patients with rheumatoid arthritis currently using glucocorticoids; RA−GCs, glucocorticoid-naive patients with rheumatoid arthritis.