Table 2.

Differences in carbohydrate metabolism molecules and insulin resistance indices between patients with RA and controls.

Variables	Controls, n = 210	RA, n = 151	Univariate Model, p	Adjusted Model, p	Adjusted Model + GC, p	Propensity Score, p
Glucose, mg/dl	90 ± 10	88 ± 19	0.21	0.36	0.92	0.50
Insulin, U/ml	9.8 ± 6.5	13.0 ± 13.4	0.007	0.062	0.079	0.10
C-peptide, ng/ml	1.53 ± 0.77	3.37 ± 2.94	< 0.001	< 0.001	< 0.001	< 0.001
Insulin:C-peptide molar ratio	0.14 ± 0.07	0.08 ± 0.02	< 0.001	< 0.001	< 0.001	< 0.001
HOMA2 insulin
HOMA2-IR	1.27 ± 0.82	1.65 ± 1.69	0.011	0.062	0.095	0.117
HOMA2-%S	108 ± 75	105 ± 53	0.65	0.011	0.003	0.011
HOMA2-%β	111 ± 45	134 ± 69	< 0.001	0.33	0.12	0.34
HOMA2 C-peptide
HOMA2-IR	1.13 ± 0.58	2.49 ± 2.35	< 0.001	< 0.001	< 0.001	< 0.001
HOMA2-%S	115 ± 75	67 ± 41	< 0.001	< 0.001	< 0.001	< 0.001
HOMA2-%β	104 ± 36	180 ± 82	< 0.001	< 0.001	< 0.001	< 0.001

Data expressed as mean (± SD). Analytical data represent the unadjusted values. Molar ratio of circulating insulin to circulating C-peptide is shown using pmol/l units. All measurements refer to serum. Values in bold face are statistically significant. RA: rheumatoid arthritis; HOMA: homeostasis model assessment; IR: insulin resistance; %S: insulin sensitivity; %β: β-cell production; GC: glucocorticoids.