Uric acid is a strong independent predictor of renal dysfunction in patients with rheumatoid arthritis

Table 1 Characteristics of the patients with rheumatoid arthritis (n = 350)

Characteristics		P value
Age in years, mean ± SD	61.8 ± 11.8	< 0.001^a
Female gender, number (percentage)	251 (71.7)	NS^b
White-British race, number (percentage)	336 (96)	NS^b
RF-positive, number (percentage)	238 (68)	NS^b
Smoking status, number (percentage)
Never smoked	157 (44.8)	NS
Ex-smoker	133 (38)
Current smoker	60 (17.2)
Pack-years, median (quartiles)	13.5 (5–30)	NS^c
BMI in kg/m², mean ± SD	27.1 ± 5.1	NS^a
RA duration in years, median (quartiles)	10 (4–19)	0.01^c
Disease activity (DAS28), mean ± SD	4.2 ± 1.37	NS^a
CRP in mg/L, median (quartiles)	16.8 (5–20.7)	NS^c
Hypertension, number (percentage)	256 (73.1)	0.008^b
Systolic BP in mm Hg, mean ± SD	143.4 ± 20.9	0.002^a
Diastolic BP in mm Hg, mean ± SD	78.9 ± 11.4	NS^a
Total CHOL in mmol/L, mean ± SD	5.2 ± 1.2	0.018^a
HDL CHOL in mmol/L, mean ± SD	1.6 ± 0.45	NS^a
TG in mmol/L, median (quartiles)	1.43 (1–1.6)	0.001^c
Diabetes mellitus, number (percentage)	25 (7.1)	NS^b
HOMA IR, median (quartiles)	1.95 (1.2–3.3)	0.05^c
QUICKI, mean ± SD	0.34 ± 0.04	0.05^a
DMARDs, number (percentage)	303 (86.5)	NS^b
MTX, number (percentage)	196 (56)	NS^b
MTX dose in mg, median (quartiles)	10 (7.5–18.7)	NS^c
Prednisolone, number (percentage)	110 (31.4)	NS^b
Prednisolone dose in mg, median (quartiles)	7.5 (4.3–10)	NS^c
NSAIDs, number (percentage)	68 (19.4)	NS^b
COX-II inhibitors, number (percentage)	31 (8.8)	NS^b
ACE inhibitors, number (percentage)	91 (26)	0.001^b
Diuretics, number (percentage)	87 (24.8)	0.02^b
Aspirin, number (percentage)	57 (16.2)	NS^b

P values represent the significance of the association with glomerular filtration rate. The symbols after P values show the corresponding statistical test: ^afor Pearson correlation, ^bfor t test and ^cfor Spearman correlation. ACE: angiotensin-converting enzyme; BMI: body mass index; BP: blood pressure; CHOL: cholesterol; COX-II: cycloxygenase II; CRP: C-reactive protein; DAS28: disease activity score using 28 joint counts; DMARD: disease-modifying antirheumatic drug; HDL: high-density lipoprotein; HOMA IR: homeostasis model assessment of insulin resistance; MTX: methotrexate; NS: nonsignificant; NSAID: nonsteroidal anti-inflammatory drug; QUICKI: quantitative insulin sensitivity check index; RA: rheumatoid arthritis; RF: rheumatoid factor; SD: standard deviation; TG: triglycerides.

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