Table 1.
Clinical, demographic and laboratory measurements at the time of urinary biomarker quantification
| Variables | Exploratory Cohort 1 (UK JSLE Cohort) | Validation Cohort 2 [Einstein Lupus Cohort (USA)] | ||||
|---|---|---|---|---|---|---|
| Active-LNa (n = 15) | Non-LNa ( n = 46) | p c b | Active-LNa (n = 16) | Non-LNa (n = 14) | p c b | |
| Age at time of analysis (years) | 16 [15–17] | 15 [14–18] | ns | 15 [14–17] | 18 [15–19] | ns |
| Disease duration (years) | 2.8 [0.7–3.9] | 2.4 [0.8–4.8] | ns | 3.1 [1.2–4.8] | 1.7 [0.5–5.6] | ns |
| Femalec | 13 (86.7) | 35 (62.5) | ns | 16 (100) | 10 (71) | ns |
| ACRd | 5 [4–7] | 5 [4–7] | ns | 5 [5.0–5.8] | 5 [4.5–6.0] | ns |
| Ethnicitye | ||||||
| Caucasian | 2 (13) | 23 (50) | 0 (0) | 0 (0) | ||
| Africanf | 3 (20) | 5 (11) | 11 (69) | 5 (36) | ||
| Hispanic | 0 (0) | 0 (0) | 5 (31) | 8 (57) | ||
| Caribbean | 2 (13) | 2 (4) | ns | 0 (0) | 0 (0) | ns |
| Mixed race | 3 (20) | 0 (0) | 0 (0) | 0 (0) | ||
| Indian | 3 (21) | 11 (24) | 0 (0) | 1 (7) | ||
| Chinese | 2 (13) | 5 (11) | 0 (0) | 0 (0) | ||
| Medication useg | ||||||
| Prednisolone | 12 (80) | 21 (46) | ns | 14 (88) | 12 (86) | ns |
| Mycophenolate mofetil | 11 (73) | 19 (41) | ns | 7 (44) | 3 (21) | ns |
| Cyclophosphamide ever | 3 (20) | 2 (4) | ns | 9 (56) | 4 (29) | ns |
| Rituximab ever | 5 (33) | 0 (0) | 0.02 | 6 (38) | 5 (36) | ns |
| ACEi/AT2 | 4 (27) | 6 (13) | ns | 10 (63) | 1 (7) | 0.03 |
| Glomerular filtration rateh | 100 [70–112] | 116 [105–127] | ns | 126 [90–160] | 110 [100–123] | ns |
| Urinary albumin-to-creatinine (Cr) ratio (mg/mmolCr) | 92 [23–153] | 1 [1–2] | <0.01 | 555 [137–2059] | 9 [3–19] | 0.03 |
| Serum creatinine (μmol/L) | 57 [50–86] | 53 [46–61] | ns | 53 [44–71] | 66 [62–73] | ns |
| dsDNA (IU/L) | 48 [15–263] | 2 [0.1–52] | ns | 156 [96–179] | 87 [23–178] | ns |
| C3 (g/L) | 1.0 [0.5–1.2] | 1.1 [1–1.2] | ns | 0.8 [0.7–1.0] | 1.0 [0.8–1.2] | ns |
| ESR (mm/h)i | 55 [20–90] | 9 [3–23] | <0.01 | − | − | − |
Data are expressed as median values with the interquartile range (IQ) in square brackets, or as numbers with the percentage in parenthesis, as appropriate
JSLE, Juvenile-onset systemic lupus erythematosus; LN, lupus nephritis; ACEi/AT2, angiotensin-converting enzyme inhibitor/angiotensin 2 blocker; dsDNA, anti-double-stranded DNA antibody; C3, complement component 3; ESR, erythrocyte sedimentation rate
aClassification of the patients into active-LN/Non-LN groups is described in section Urine sample selection
b p values are Bonferroni-corrected p values (p c) from Chi-squared tests or univariate binary regression, as appropriate. ns = p c > 0.05
cGender data missing on one Cohort 1 patient
dACR, Number of American College of Rheumatology criteria for systemic lupus erythematosus (SLE) fulfilled at diagnosis
eSelf-reported ethnicity data shown
fWithin Cohort 2, African American patients were also included in this category
gCurrent medication use is described for regular medications; those medications taken in courses/intermittently are described as having been used ‘ever’
hmls/min
iESR was not routinely measured in Cohort 2