Association of risk factors and disease characteristics with HOMA-IR and MCRest
| Patient characteristics | β (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 HOMA-IR as dependent variable | |||
| RA−GC* | 0.6 (0.08, 1.0) | ||
| RA+GC* | 1.0 (0.6, 1.5) | ||
| Waist circumference | 0.02 (−0.01 to 0.04) | 0.02 (−0.003 to 0.05) | 0.03 (0.0002 to 0.06) |
| Age | 0.002 (−0.02 to 0.02) | 0.008 (−0.007 to 0.02) | 0.006 (−0.01, 0.02) |
| BMI | 0.03 (−0.05 to 0.1) | 0.05 (−0.2 to 0.1) | 0.03 (−0.04 to 0.1) |
| Female gender | 0.2 (−0.2 to 0.6) | −0.1 (−0.5 to 0.3) | −0.06 (−0.5 to 0.4) |
| Cumulative GC dose (mg)† | 0.01 (0.003 to 0.02) | 0.01 (0.003 to 0.02) | |
| Daily GC dose† (mg) | 0.01 (−0.04 to 0.05) | 0.005 (–0.04 to 0.05) | |
| DAS28‡ | 0.1 (−0.04 to 0.3) | ||
| Any erosions of the hands or feet | −0.3 (−0.7 to 0.2) | ||
| Past DMARDs (n)§ | −0.06 (−0.2 to 0.05) | ||
| ACPA | 0.2 (−0.7 to 0.2) | ||
| Disease duration (years) | 0.02 (−0.008 to 0.04) | ||
| Four multivariate regression analysis models with MCRest as dependent variable | |||
| RA−GC* | 0.4 (−0.5 to 1.3) | ||
| RA+GC* | 0.4 (−0.5 to 1.2) | ||
| Waist | −0.02 (−0.07 to 0.03) | −0.06 (−0.1 to 0.01) | −0.09 (−0.2 to −0.02) |
| Age | −0.03 (−0.06 to 0.005) | −0.07 (−0.1 to −0.03) | −0.07 (−0.1 to −0.03) |
| BMI | −0.3 (−0.4 to −0.1) | −0.2 (−0.4 to −0.06) | −0.1 (−0.3 to −0.06) |
| Female gender | −0.8 (−1.6 to 0.08) | −0.08 (−1.3 to 1.1) | −0.5 (−1.7 to 0.7) |
| Cumulative GC dose (g)† | 0.002 (−0.01 to 0.04) | 0.01 (−0.01 to 0.04) | |
| Daily GC dose† (mg) | −0.07 (−0.19 to 0.05) | −0.04 (−0.2 to 0.08) | |
| DAS28‡ | −0.5 (−0.9 to −0.1) | ||
| Any erosions of the hands or feet | 0.8 (−0.3 to 2.0) | ||
| Past DMARDs (n)§ | 0.2 (−0.06 to 0.5) | ||
| ACPA | −0.7 (−1.8 to 0.4) | ||
| Disease duration (years) | 0.03 (−0.04 to 0.1) | ||
Three multivariate models, correcting for age, BMI and female gender were used to test associations with insulin sensitivity parameters HOMA-IR and MCRest: (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 examination, ACPA).
Significant associations (p<0.05) are depicted in bold
↵* RA−GC and RA+GC populations are tested with the healthy control group used as the reference population; only patients with RA with normal glucose tolerance during OGTT and without first-degree relatives with type 2 diabetes mellitus were included in the model for the comparison with healthy controls.
↵† 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 is depicted, whereas ESR was also significantly associated with MCRest in this model.
↵§ 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; DMARD, disease-modifying antirheumatic drug; ESR, erythrocyte sedimentation rate; GC, glucocorticoid; HOMA-IR, homoeostatic model assessment of insulin resistance; MCRest, Insulin Sensitivity Index by Stumvoll; OGTT, oral glucose tolerance test; RA, rheumatoid arthritis.