Table 1

Demographics, RA characteristics and risk factors for renal impairment in the cohort

Filtration rate value ml/minute per 1.73 m2
>90 (n = 129)60–90 (n = 220)<60 (n = 51)p Value
Age, years (SD)54.60 (12.58)62.91 (10.49)69.77 (7.17)<0.001
Sex female, n (%)96 (74.4)152 (69)43 (84.3)0.085
RF positive, n (%)92 (71.3)164 (74.5)39 (76.4)0.568
Anti-CCP, n (%)61 (47.2)107 (48.6)29 (56.8)0.939
Disease duration, years (IQR)9 (12)10 (13)13 (15.75)0.031
Extra-articular disease
 Sicca, n (%)57 (44.1)121 (55)29 (56.8)0.089
 Nodules, n (%)33 (25.5)64 (29.1)20 (39.2)0.152
 Other,* n (%)21 (16.2)42 (19.1)11 (21.5)0.028
Disease severity
 HAQ (IQR)1.37 (1.37)1.50 (1.62)1.87 (1.25)0.323
Disease activity
 DAS28 (SD)4.05 (1.44)4.12 (1.30)4.68 (1.60)0.275
Inflammatory markers
 ESR, mm/h (IQR)19 (26)20 (25)27 (26.25)0.063
 CRP, mg/l (IQR)10 (16)8 (11)10 (23.25)0.436
Smoking status
 Never smoked, n (%)57 (44.1)96 (43.6)23 (45.1)0.675
 Ex-smoker, n (%)52 (40.3)82 (37.2)17 (33.3)0.784
 Current smoker, n (%)22 (17)35 (15.9)8 (15.6)0.527
 Pack-years (IQR)12.4 (20)13.2 (20)9.6 (15.7)0.885
Blood pressure
 Hypertension (%)79 (61.2)160 (72.7)47 (92.1)0.001
 SBP, mm Hg (SD)138.72 (20.42)142.26 (19.60)147.26 (20.32)0.003
 DBP, mm Hg (SD)78.49 (11.36)79.61 (10.71)77.74 (13.36)0.943
Dyslipidaemia
 Total cholesterol, mmol/l (SD)5.14 (1.14)5.27 (1.08)5.39 (1.65)0.042
 HDL-cholesterol, mmol/l (SD)1.57 (0.44)1.61 (0.42)1.53 (0.43)0.738
 Triglycerides, mmol/l (SD)1.29 (0.69)1.40 (0.62)1.71 (0.93)0.002
Insulin resistance
 Type 2 DM, n (%)16 (12.4)18 (8.1)8 (15.6)0.361
 HOMA IR (IQR)1.56 (2.0)1.87 (1.86)2.41 (2.7)0.002
 QUICKI (SD)0.35 (0.04)0.34 (0.03)0.33 (0.04)0.002
Obesity
 BMI (SD)26.78 (5.67)28.19 (4.67)27.51 (4.30)0.062
Other
 SUA, mmol/l (SD)270.36 (76.82)314.82 (75.94)388.76 (109.15),0.001
 CVD (%)21 (16.2)44 (20)18 (35.3)0.020
Drugs
 DMARD, n (%)114 (88.3)195 (88.6)41 (80.4)0.072
 Methotrexate, n (%)61 (47.2)138 (62.7)25 (49)0.261
 Anti-TNF, n (%)16 (12.4)24 (10.9)6 (11.7)0.710
 Steroids, n (%)33 (25.5)68 (30.9)24 (47)0.023
 NSAID, n (%)33 (25.5)37 (16.8)9 (17.6)0.060
 Coxibs, n (%)11 (8.5)14 (6.3)7 (13.7)0.675
  • Results are expressed as percentages, median (interquartile range) or mean (SD) as appropriate. p Values are for trends between glomerular filtration rate groups. *Patients with systemic or nailfold vasculitis (including neuropathy, ulcers purpura, etc), pulmonary fibrosis, serositis, scleritis or Felty's syndrome. Anti-CCP, anti-cyclic citrullinated peptide; BMI, body mass index; CRP, C-reactive protein; CVD, cardiovascular disease; DAS28, disease activity score in 28 joints; DBP, diastolic blood pressure; DM, diabetes mellitus; DMARD, disease-modifying antirheumatic drug; ESR, erythrocyte sedimentation rate; HAQ, health assessment questionnaire; HDL, high-density lipoprotein; HOMA IR; homeostasis model assessment of insulin resistance; NSAID, non-steroidal anti-inflammatory drug; QUICKI, quantitative insulin sensitivity check index; RA, rheumatoid arthritis; RF, rheumatoid factor; SBP, systolic blood pressure; SUA, serum uric acid; TNF, tumour necrosis factor.