Table 1

Baseline characteristics of the rheumatoid arthritis patients included in the study*

Insulin resistance

All patients (n = 61)

Low †

(n = 31)

High †

(n = 30)

P value #


Age (years)

60 (57, 63)

58 (54, 63)

62 (58, 67)

0.157

Gender (% female)

70

74

63

0.360

Disease duration (years)

7.2 (5.6, 9.3)

6.9 (4.8, 10.1)

7.5 (5.2, 10.9)

0.727

DAS28

5.8 (5.5, 6.1)

5.4 (5.1, 5.8)

6.3 (5.8, 6.7)

0.011

HAQ

1.0 (0.8, 1.2)

0.9 (0.6, 1.1)

1.1 (0.9, 1.4)

0.129

C-reactive protein (mg/dl)

1.4 (0.8, 2.1)

1.2 (0.2, 2.1)

1.7 (0.7, 2.6)

0.134

ESR (mm/hr)

35 (29, 40)

33 (24, 42)

36 (28, 44)

0.559

Insulin (μIU/ml)

13.5 (10.4, 17.4)

7.0 (5.1, 9.5)

26.7 (21.0, 33.8)

< 0.001

FBG (mg/dl)

96 (89, 103)

87 (80, 93)

107 (95, 119)

< 0.001

HOMA-IR §

3.2 (2.4, 4.3)

1.5 (1.1, 2.0)

7.0 (5.2, 9.4)

< 0.001

HOMA-B §

159 (122, 207)

123 (77, 195)

210 (168, 263)

0.013

QUICKI

0.33 (0.31, 0.34)

0.36 (0.34, 0.39)

0.29 (0.28, 0.30)

< 0.001

TC (mg/dl)

221 (206, 235)

226 (204, 247)

216 (195, 236)

0.471

HDL-C (mg/dl)

54 (50, 57)

56 (52, 61)

51 (46, 57)

0.095

LDL-C (mg/dl)

137 (125, 150)

144 (126, 162)

131 (114, 148)

0.278

TC/HDL-C

4.3 (3.9, 4.6)

4.1 (3.7, 4.5)

4.4 (3.9, 4.9)

0.399

LDL-C/HDL-C

2.7 (2.4, 2.9)

2.6 (2.3, 3.0)

2.7 (2.3, 3.1)

0.868

Triglycerides (mg/dl)

151 (132, 171)

129 (105, 152)

175 (144, 206)

0.015

Lpa (mg/dl)

12.8 (9.5, 17.1)

10.1 (6.6, 15.4)

16.4 (10.9, 24.8)

0.130

apoA (mg/dl)

162 (155, 169)

168 (158, 177)

156 (146, 166)

0.079

apoB (mg/dl)

99 (92, 107)

100 (88, 112)

99 (89, 109)

0.762

apoB/apoA

0.63 (0.58, 0.69)

0.61 (0.52, 0.70)

0.66 (0.57, 0.74)

0.364

Homocysteine (μmol/l)

17.5 (15.7, 19.3)

17.8 (15.1, 20.5)

17.2 (14.6, 19.9)

0.584

Body weight (kg)

75 (71, 79)

73 (68, 78)

77 (7, 83)

0.203

Body mass index (kg/m2)

29.1 (27.5, 30.7)

28.6 (26.2, 30.9)

29.7 (27.4, 32.1)

0.371

Waist circumference (cm)

101 (97, 105)

100 (94, 106)

102 (97, 107)

0.207

SBP (mmHg)

127 (123, 131)

125 (118, 132)

130 (125, 134)

0.024

DBP (mmHg)

77 (75, 79)

78 (74, 81)

76 (73, 79)

0.672

Metabolic syndrome (%) **

41

19

63

0.001

Statin use (%)

19

13

24

0.333

Tobacco use (%)

19

23

14

0.506

Coronary heart disease (%)

14

10

17

0.472

Hypertension (%)

61

58

63

0.795

Antihypertensive therapy (%)

46

48

43

0.799

MTX (%)

69

65

73

0.582

MTX dose (mg/week)

14.8 (14.0, 15.7)

15.9 (14.7, 17.1)

13.9 (12.7, 15.0)

0.033

GC (%)

21

19

23

0.762

GC dose (mg/day)

8.8 (5.6, 12.1)

7.9 (5.3, 10.5)

9.6 (3.0, 16.2)

0.705


* Except where indicated otherwise, values are the mean (95% confidence interval)

† The median Homeostasis Model Assessment for insulin resistance (HOMA-IR) value at baseline was used to assign patients into low (HOMA-IR ≤ 3.18, n = 31) or high (HOMA-IR > 3.18, n = 30) insulin resistance group

# P value for the comparison between low and high insulin resistance groups

§ Statistical comparisons were performed using log transformed values. Values represent the geometric mean

** According to the Adult Treatment Panel (ATP) III criteria for the definition of the metabolic syndrome

DAS28: disease activity score of 28 joints; HAQ: health assessment questionnaire; ESR: erythrocyte sedimentation rate; FBG: fasting blood glucose; QUICKI: Quantitative Insulin Sensitivity Check Index; TC: total cholesterol; HDL-C: high-density lipoprotein cholesterol; LDL-C: low-density lipoprotein cholesterol; Lpa: lipoprotein a; apo: apolipoprotein; SBP: systolic blood pressure; DBP: diastolic blood pressure; MTX: methotrexate; GC: glucocorticoids.

Stagakis et al. Arthritis Research & Therapy 2012 14:R141   doi:10.1186/ar3874

Open Data