Table 2.

Metabolic risk factors, systemic inflammation, and disease characteristics associated with insulin resistance (IR) indexes and retinol-binding protein 4.

	Log β Coefficient (95% CI), p
	Controls, n = 115		RA, n = 101
	HOMA-IR	HOMA-%B	HOMA-IR	HOMA-%B
Demographic data
Age, yrs	0.01 (0.00–0.02), 0.02^†	0.00 (−0.01–0.01)	0.00 (−0.02–0.02), 0.83	0.01 (−0.03–0.00), 0.06
Male	0.16 (−0.21–0.54), 0.39	−0.09 (−0.41–0.24), 0.60	−0.24 (−0.76–0.27), 0.35	−0.52 (−0.92 to −0.12), 0.01^†
Metabolic risk factors
Body mass index, kg/m²	0.03 (0.01–0.06), 0.01^†	0.02 (−0.00–0.04), 0.07	0.06 (0.03–0.10), 0.00^†	0.02 (−0.01–0.05), 0.16
Waist circumference, cm^*	0.03 (0.01–0.06), 0.02^†	0.02 (0.00–0.04), 0.02^†	0.02 (0.01–0.04), 0.00^†	0.00 (−0.01–0.02), 0.32
Hip circumference, cm^*	0.01 (−0.01–0.02), 0.33	0.00 (−0.01–0.01), 0.89	0.03 (0.02–0.04), 0.00^†	0.01 (0.00–0.02), 0.02^†
Waist-to-hip ratio^*	−0.03 (−0.23–0.16), 0.73	0.03 (−0.12–0.18), 0.65	−0.34 (−0.55 to −0.14), 0.00^†	−0.17 (−0.34 to −0.01), 0.04^†
Hypertension	0.39 (0.18–0.61), 0.00^†	0.18 (−0.01–0.38), 0.06	0.48 (0.11–0.86), 0.01^†	0.10 (−0.21–0.41), 0.53
Metabolic syndrome	0.56 (0.30–0.81), 0.00^†	0.15 (−0.08–0.39), 0.20	0.57 (0.17–0.97), 0.01^†	0.06 (−0.40–0.28), 0.73
Systemic inflammation
ESR, mm/h	−0.01 (−0.02–0.01), 0.46	0.00 (−0.10–0.02), 0.65	−0.00 (−0.01–0.01), 0.66	0.00 (−0.01–0.01), 0.52
CRP, mg/l	0.03 (−0.00–0.07), 0.07	0.02 (−0.01–0.05), 0.21	−0.01 (−0.02–0.00), 0.05	0.01 (−0.02–0.01), 0.32
RA-related data
Disease duration, yrs			−0.02 (−0.06–0.01), 0.19	0.02 (−0.01–0.04), 0.27
DAS28-ESR			−0.00 (−0.14–0.13), 0.96	−0.01 (−0.12–0.10), 0.81
HAQ			−0.01 (−0.30–0.29), 0.97	0.03 (−0.27–0.21), 0.83
Positive rheumatoid factor			0.00 (−0.39–0.39), 0.99	0.10 (−0.21–0.42), 0.52
Current nonbiologic DMARD			−0.28 (−1.35–0.79), 0.60	0.16 (−1.10–0.79), 0.74
Patients with RA taking glucocorticoids, n = 46
Current prednisone			0.23 (−0.14–0.60), 0.22	0.01 (−0.28–0.31), 0.93
Prednisone, (mg/day/last 3 mos)			0.01 (−0.23–0.24), 0.96	0.02 (−0.20–0.24), 0.87

↵* Waist and hip circumference, and waist-to-hip ratio relation with HOMA-IR and HOMA-%B were adjusted for sex. β coefficients of HOMA-IR, HOMA-%B, and RB4 are expressed log-transformed.
↵† Significant associations (p < 0.05). HOMA: homeostasis model assessment; ESR: erythrocyte sedimentation rate; CRP: C-reactive protein; DAS28: Disease Activity Score; DMARD: disease-modifying antirheumatic drug; HAQ: Health Assessment Questionnaire; RA: rheumatoid arthritis.