Comparative analysis of demographic, SpA-related characteristics, CV risk factors, and disease activity variables according to eGFR in patients with SpA. Values are n (%) unless otherwise specified.
| Characteristics | Total, n = 2098 | eGFR ≥ 60 ml/min/1.73 m2, n = 1945 | eGFR < 60 ml/min/1.73 m2, n = 153 | p |
|---|---|---|---|---|
| Demographic and SpA-related characteristics | ||||
| Age, yrs | 45.3 (13.7) | 44.6 (13.3) | 53.6 (14.6) | < 0.001* |
| Age < 45 yrs | 1083 (51.6) | 1039 (53.4) | 44 (28.8) | < 0.001* |
| Age 45–59 yrs | 697 (33.2) | 646 (33.2) | 51 (33.3) | |
| Age ≥ 60 yrs | 318 (15.2) | 206 (13.4) | 58 (37.9) | |
| Male | 1332 (63.5) | 1244 (64) | 88 (57.2) | 0.11 |
| SpA duration, yrs, mean (SD) | 8.6 (9) | 8.6 (8.9) | 9.8 (10) | 0.70 |
| HLA-B27 positivity | 1126 (73.1) | 1073 (74) | 53 (59.6) | 0.003* |
| Axial involvement | 1805 (86.1) | 1677 (86.3) | 267 (13.7) | 0.37 |
| Peripheral involvement | 1283 (61.2) | 1174 (60.4) | 109 (71.2) | 0.008* |
| Sacroiliitis on radiograph | 1315 (62.8) | 1220 (62.8) | 95 (62.5) | 0.23 |
| Sacroiliitis on MRI | 558 (26.6) | 520 (26.8) | 38 (25) | 0.75 |
| Extraarticular manifestations | 488 (23.3) | 454 (23.3) | 34 (22.2) | 0.75 |
| CV characteristics | ||||
| Hypertension | 753 (35.9) | 676 (34.8) | 77 (50.3) | < 0.001* |
| Systolic blood pressure, mmHg, mean (SD) | 124.2 (15.7) | 123.9 (15.5) | 127.6 (16.8) | 0.009* |
| Diastolic blood pressure, mmHg, mean (SD) | 77.2 (10.2) | 77.1 (10.2) | 78.4 (10) | 0.15 |
| Diabetes | 238 (11.3) | 210 (10.8) | 28 (18.3) | 0.005* |
| Current smoker | 526 (25.1) | 498 (25.6) | 28 (18.3) | 0.06 |
| Previous smoker | 524 (25) | 476 (22.7) | 48 (31.3) | |
| Never smoker | 1046 (49.9) | 969 (49.9) | 77 (50.3) | |
| LDL cholesterol, g/l, mean (SD) | 1.30 (1) | 1.30 (1) | 1.2 (0.7) | 0.73 |
| HDL cholesterol, g/l, mean (SD) | 0.7 (0.9) | 0.7 (0.9) | 0.7 (0.7) | 0.67 |
| BMI, mean (SD) | 26.7 (6.0) | 26.8 (6.0) | 26.6 (5.6) | 0.76 |
| Framingham risk score, mean (SD) | 8.3 (8.2) | 7.9 (7.9) | 12.8 (10.2) | < 0.001* |
| SpA activity scores | ||||
| BASDAI, mean (SD) | 3.6 (2.4) | 3.5 (2.4) | 4.1 (2.4) | 0.001* |
| BASDAI < 4/10 | 1230 (58.8) | 1154 (59.5) | 763(49.7) | 0.02 |
| BASDAI ≥ 4/10 | 862 (41.2) | 785 (40.5) | 77 (50.3) | |
| ASDAS-ESR, mean (SD) | 2.3 (1.1) | 2.3 (1.1) | 2.8 (1.1) | < 0.001* |
| ASDAS-CRP, mean (SD) | 1.9 (1.1) | 1.9 (1.1) | 2.4 (1.1) | < 0.001* |
| PGA, mean (SD) | 3.1 (2) | 3.1 (2) | 3.7 (2.1) | < 0.001* |
| ESR, mm in 1st h, median (IQR) | 12 (6–24) | 12 (5–23) | 22 (6–24) | < 0.001* |
| CRP, mg/dl, median (IQR) | 0.1 (0.03–0.32) | 0.1 (0.03–0.3) | 0.2 (0.05–1.2) | < 0.001* |
| SpA severity variables | ||||
| BASFI, mean (SD) | 3.1 (2.7) | 2.9 (2.7) | 4.4 (2.6) | < 0.001* |
| EQ-5D, mean (SD) | 0.58 (0.3) | 0.59 (0.31) | 0.39 (0.31) | < 0.001* |
| Hip replacement | 81 (4) | 71 (3.8) | 10 (6.9) | 0.16 |
| Bamboo spine | 166 (8) | 154 (8) | 12 (7.8) | 0.9 |
| SpA treatment | ||||
| Current DMARD | 1641 (78.2) | 1523 (78.3) | 118 (77.1) | 0.73 |
| Anti-TNF | 1017 (48.5) | 954 (49.1) | 63 (41.2) | 0.06 |
| MTX | 727 (34.7) | 672 (34.6) | 55 (36.0) | 0.73 |
| Current steroids | 257 (12.3) | 237 (12.2) | 20 (13.1) | 0.77 |
| Cumulative steroid dose, mg, median (IQR) | 2050 (600–7300) | 2050 (650–7420) | 2120 (365–3916) | 0.33 |
| NSAID intake, last 3 mos | 1429 (68.3) | 1334 (68.8) | 95 (62.1) | 0.09 |
| ASAS-NSAID score, median (IQR) | 12.1 (0–57) | 12.6 (0–57) | 7.5 (0–50) | 0.18 |
| NSAID % days of intake since onset | 57.8 | 51 | 58.4 | 0.008* |
↵* p < 0.05. SpA: spondyloarthritis; CV: cardiovascular; eGFR: glomerular filtration rate in ml/min/1.73 m2 estimated by the MDRD equation; MDRD: Modification of Diet in Renal Disease; sacroiliitis on radiograph: at least grade 2 bilateral or 3 unilateral; sacroiliitis on MRI: according to the ASAS definition; MRI: magnetic resonance imaging; ASAS: Assessment of Spondyloarthritis international Society; extraarticular manifestations: psoriasis, uveitis, or inflammatory bowel disease; LDL: low-density lipoprotein; HDL: high-density lipoprotein; BMI: body mass index; BASDAI: Bath Ankylosing Spondylitis Activity Index; ASDAS: Ankylosing Spondylitis Disease Activity Score; ESR: erythrocyte sedimentation rate; CRP: C-reactive protein; PGA: physician’s global assessment; IQR: interquartile range; BASFI: Bath Ankylosing Spondylitis Functional Index; DMARD: disease-modifying antirheumatic drug; TNF: tumor necrosis factor; MTX: methotrexate; NSAID: nonsteroidal antiinflammatory drugs.