LN | ANR-SLE | INR-SLE | Population controls | P value | |
Patients, n | 84 | 63 | 73 | 48 | ns |
Sex, female (%) | 89.3 | 90.5 | 81.3 | 89.0 | ns |
Age, M (SD) | 36.2 (13) | 37.9 (12) | 47.7 (16) | 38.6 (15) | 0.008 |
Disease duration | 2 (0–8) | 6 (1–12) | 7 (4.5–15.5) | NA | <0.0001 |
Ethnicity (Caucasian/Asian/African/Hispanic), n | 75/3/2/4 | 51/6/6/0 | 62/6/2/3 | 44/2/0/2 | ns |
p-creatinine (µmol/L) | 68 (57–83) | 66 (58–73) | 67 (58–76) | 63 (56–71) | ns |
eGFR, mL/min/1.732 | 105 (77–123) | 103 (89–121) | 95 (79–109) | NA | 0.09 |
u-ACR (mg/mmol) | 45.3 (19.0–76.1) | 2.8 (1.5–3.8) | 1.4 (0.9–2.4) | 0.4 (0.3–0.5) | <0.0001 |
Positive a-dsDNA*, % | 64 | 46 | 25 | NA | <0.0001 |
Low C3†, % | 70 | 25 | 0 | NA | <0.0001 |
Low C4†, % | 75 | 45 | 15 | NA | <0.0001 |
SLEDAI-2K score | 12 (8–18) | 6 (4–8) | 1 (0–2) | NA | <0.0001 |
No treatment, n (%) | 14 (16.6) | 7 (11.1) | 23 (31.5) | NA | ns |
Prednisolone, n (%) | 63 (75.0) | 45 (71.4) | 29 (39.7) | NA | <0.0001 |
Prednisolone (mg‡), M (SD) | 15 (13) | 8.5 (9.4) | 3.3 (5.7) | NA | <0.0001 |
Prednisolone ≥10 mg, % | 55.5 | 36.5 | 15.0 | NA | LR25.7<0.0001 |
Hydroxychloroquine, n (%) | 39 (46) | 38 (60) | 35 (48) | NA | ns |
DMARD any, n (%) | 38 (45) | 29 (46) | 18 (25) | NA | <0.0001 |
dt-p-IL-16, n (%) | 79 (100) | 60 (100) | 47 (100) | 38 (100) | ns |
p-IL-16 (ng/mL) | 0.43 (0.3–0.8) | 0.36 (0.2–1.0) | 0.25 (0.2–0.5) | 0.2 (0.16–0.5) | 0.0028 |
p-IL-16 (ng/mL), M (SD) | 6.2 (0.8) | 6.09 (0.98) | 5.8 (0.75) | 5.7 (0.89) | ns |
dt-u-IL-16, n (%) | 40 (47.6) | 4 (6.3) | 13 (17.8) | 2 (4.3) | <0.0001 |
u-IL-16 (pg/mL) | 3§ (3§−33.1) | n-dt¶ | n-dt¶ | n-dt¶ | <0.0001 |
u-IL-16 (pg/mL), M (SD) | 27.0 (42.5) | 5.2 (10.4) | 9.8 (34.2) | 3.4 (2.4) | <0.0001 |
All variables are presented as median and IQR, if not indicated otherwise.
*Data on a-dsDNA status were missing in 9 patients with LN, 17 with ANR-SLE and 18 with INR-SLE.
†Data on C3 and C4 status were missing in 27 patients with LN, 3 with ANR-SLE and 9 with INR-SLE.
‡Prednisolone dose or equivalent steroid dose.
§3 is an arbitrary value for non-detectable levels for analysis by non-parametric tests.
¶Only undetectable levels found in the IQR.
ACR, morning albumin to creatinine ratio; a-dsDNA, anti-double-stranded DNA; ANR-SLE, active non-renal SLE; DMARD, disease-modifying antirheumatic drugs (detailed information is provided in online supplemental material); dt, detectable (detection limit was defined by ELISA manufacturer’s recommendations as >9 pg/mL); eGFR, glomerular filtration rate; IL, interleukin; INR-SLE, inactive non-renal SLE; LN, lupus nephritis; LR, likelihood ratio; M, mean; NA, data not analysed; n-dt, non-detectable; p, plasma; SLE, systemic lupus erythematosus; SLEDAI-2K, Systemic Lupus Erythematosus Disease Activity Index 2000; u, urine.