Table 1.
Baseline characteristics and serum biomarker concentrations of the study cohort stratified by development of a composite renal and mortality end point (n=139)
| Characteristic | Data Available, n (%) | Total Cohort, n=139 | Did Not Develop Composite End Point (n=83)a | Developed Composite End Point (n=56)a |
| Clinical parameters | ||||
| Age (yr), (mean±SD) | 139 (100) | 63±17 | 60±17 | 67±15 |
| Male, n (%) | 139 (100) | 78 (56) | 38 (46) | 40 (71) |
| Diabetes mellitus, n (%) | 139 (100) | 35 (25) | 11 (13) | 24 (43) |
| Hypertension, n (%) | 139 (100) | 115 (83) | 64 (77) | 51 (91) |
| Coronary artery disease, n (%) | 139 (100) | 18 (13) | 8 (10) | 10 (18) |
| CKD stage, n (%) | 139 (100) | |||
| Grade 1 | 5 (4) | 5 (6) | 0 (0) | |
| Grade 2 | 17 (12) | 16 (19) | 1 (2) | |
| Grade 3a | 22 (16) | 19 (23) | 3 (5) | |
| Grade 3b | 42 (30) | 25 (30) | 17 (30) | |
| Grade 4 | 46 (33) | 16 (19) | 30 (54) | |
| Grade 5 | 7 (5) | 2 (2) | 5 (9) | |
| CKD etiology, n (%) | 139 (100) | |||
| Diabetes | 23 (17) | 8 (10) | 15 (27) | |
| Hypertension | 12 (9) | 9 (11) | 3 (5) | |
| GN | 30 (22) | 23 (28) | 7 (13) | |
| Congenital | 8 (6) | 7 (8) | 1 (2) | |
| Polycystic kidney disease | 6 (4) | 3 (4) | 3 (5) | |
| Obstructive | 6 (4) | 2 (2) | 4 (7) | |
| Interstitial | 7 (5) | 5 (6) | 2 (4) | |
| Other/unknown | 47 (34) | 26 (31) | 21 (38) | |
| Laboratory data | ||||
| Serum creatinine (mg/dl), mean±SD | 139 (100) | 2.0±1.0 | 1.6±0.6 | 2.6±1.1 |
| CKD-EPI eGFR (ml/min per BSA), median (IQR) | 139 (100) | 33 (24–51) | 43 (31–60) | 26 (18–34) |
| uACR (mg/g), median (IQR) | 58 (42) | 127 (22–479) | 33 (18–144) | 504 (92–1249) |
| uPCR (mg/g), median (IQR) | 76 (55) | 327 (124–814) | 301 (124–637) | 345 (181–1381) |
| Merged uACR (mg/g), median (IQR)b | 113 (81) | 144 (22–532) | 104 (19–269) | 283 (83–993) |
| Hemoglobin (g/dl), mean±SD | 138 (99) | 13.0±1.7 | 13.4±1.9 | 12.3±1.2 |
| KFRE estimates (%), median (IQR) | 113 (81) | |||
| 2 year | 1.4 (0.3–6.5) | 0.6 (0.1–2.4) | 6.4 (1.6–18.7) | |
| 5 year | 5.4 (1.2–23.1) | 2.1 (0.3–9.0) | 22.5 (6.1–55.1) | |
| Multiplex biomarker values, median (IQR) | ||||
| C-reactive protein (ng/ml) | 139 (100) | 3035 (1607–8244) | 2610 (1416–5296) | 4612 (2303–15181) |
| Cystatin C (ng/ml) | 139 (100) | 3715 (2575–5000) | 3241 (2115–4384) | 4984 (3662–5739) |
| C3a-desArg (ng/ml) | 139 (100) | 1762 (1010–2877) | 2240 (1099–3392) | 1467 (947–2178) |
| D-dimer (ng/ml) | 138 (99) | 81 (41–153) | 73 (34–143) | 103 (49–172) |
| EGF (pg/ml) | 138 (99) | 91 (54–126) | 109 (58–134) | 72 (47–104) |
| FABP1 (ng/ml) | 139 (100) | 1.6 (0.7–3.0) | 1.3 (0.6–2.7) | 1.9 (1.2–3.8) |
| IL-8 (pg/ml) | 139 (100) | 3.7 (2.6–8.5) | 3.9 (2.5–8.6) | 3.6 (2.7–7.3) |
| MIP-1-α (pg/ml) | 130 (94) | 4.8 (2.6–10.6) | 3.9 (2.3–6.6) | 7.5 (3.7–15.1) |
| NGAL (ng/ml) | 137 (99) | 167 (116–253) | 137 (104–194) | 213 (173–327) |
| sTNFR1 (ng/ml) | 136 (98) | 3.0 (2.1–4.6) | 2.4 (1.9–3.2) | 4.6 (3.5–6.8) |
| sTNFR2 (ng/ml) | 138 (99) | 1.4 (0.8–2.2) | 1.1 (0.6–1.6) | 2.1 (1.3–2.5) |
Values are given as n (%) for categorical variables, or mean±SD for normally distributed continuous variables, unless otherwise indicated. Median (IQR) values are presented for continuous variables that are not normally distributed. CKD-EPI, Chronic Kidney Disease Epidemiology Collaboration; BSA, body surface area; IQR, interquartile range; uACR, urine albumin-creatinine ratio; uPCR, urine protein-creatinine ratio; KFRE, Kidney Failure Risk Equation (four-variable; non-North America); C3a-desArg, complement 3a with cleaved C-terminal arginine; FABP1, fatty acid-binding protein-1; MIP-1-α, macrophage inflammatory protein-1-α; NGAL, neutrophil gelatinase-associated lipocalin; sTNFR1, soluble TNF receptor-1; sTNFR2, soluble TNF receptor-2.
Composite end point: ≥40% decrease in CKD-EPI eGFR, doubling of serum creatinine, RRT, or mortality.
Merged uACR represents a combination of measured uACR and calculated uACR from uPCR using the validated equation of Weaver et al. (11). uACR values on the natural log scale were exponentiated such that presented values are in absolute units in milligrams per gram.