Urinary calprotectin, NGAL, and KIM-1 in the differentiation of primarily inflammatory vs. non-inflammatory stable chronic kidney diseases

Figures & data

Table 1. Concentrations of urinary biomarkers in dependence of the origin of chronic kidney disease.

Etiology of chronic kidney disease	Calprotectin (ng/ml)	NGAL (pg/ml)	KIM-1 (pg/ml)	Albumin/creatinine ratio (mg/g)
Overall CKD population, n = 143	98.6 (37.8–425.8)	12 015 (5658–23 448)	1040 (502–2672)	44.2 (9.1–320.5)
Diabetes, n = 41 (28.7%)	74.1 (33.0–217.9)	10 414 (5400–27 064)	990 (601–2444)	174.4 (34.7–678.4)
Hypertension, n = 42 (29.4%)	137.5 (38.1–562.9)	13 173 (6567–25 936)	1223 (312–3501)	18.1 (8.5–93.1)
Comb. diabetes & hypertension, n = 19 (13.3%)	63.3 (24.4–707.8)	18 741 (10 571–35 067)	1246 (623–2680)	29.6 (9–502.2)
Autosomal-dominant polycystic kidney disease, n = 7 (4.9%)	50.5 (7.7–404.9)	16 692 (4153–18 534)	1556 (455–2143)	117.2 (6.3–991.9)
Glomerulonephritis/vasculitis (IRD), n = 15 (9.8%)	155.7 (20.8–1325.0)	14 896 (5658–28 881)	1388 (833–2730)	198.9 (34.5–1205)
Others, n = 19 (13.3%)	144.30 (57.2–448.3)	9706 (3840–14 401)	651 (386–1938)	8.2 (3.6–63.13)
Non-inflammatory renal diseases (NIRD), n = 128 (89.5%)	97.0 (39.0–420.7)	11 977 (5658–22 770)	1009 (427–2669)	26.6 (8.8–264.3)
Healthy controls, n = 29 (age: 74; 58–77)	56.9 (13.3–124.6)	4765 (2449–9877)	1183 (626–2497)	0 (0–0)
Mann–Whitney U test (overall CKD population vs. healthy controls)	**p = 0.0068	***p < 0.001	p = 0.84	***p < 0.001
Mann–Whitney U test (IRD vs. NIRD)	p = 0.81	p = 0.41	p = 0.34	*p = 0.028

Data presented as median with interquartile range in brackets. CKD: chronic kidney disease; NGAL: neutrophil gelatinase-associated lipocalin; KIM-1: kidney injury molecule 1; NIRD: non-inflammatory renal disease; IRD: inflammatory renal disease.

Bold represents statistically significant values (p < 0.05).

*p < 0.05, **p < 0.01, ***p < 0.001.

Figure 1. Comparison of the CKD population with healthy controls for urinary (A) calprotectin, (B) NGAL, (C) KIM-1, and (D) ACR. Data are presented as scatter plots (logarithmic Y-axis, medians are indicated by horizontal lines). Significant differences were ***p < 0.001 and **p < 0.01 by Mann–Whitney testing. NGAL: Neutrophil gelatinase-associated lipocalin; KIM-1: kidney injury molecule-1; ACR: albumin/creatinine ratio; CKD: chronic kidney disease.

Figure 2. Discriminatory potency of biomarkers between the primarily inflammatory entities glomerulonephritis/vasculitis (IRD) vs. other entities of CKD (NIRD), illustrated by scatter plots (logarithmic Y-axis, medians are indicated by horizontal lines) of urinary (A) calprotectin, (B) NGAL, (C) KIM-1, and (D) ACR. Significant differences were *p < 0.05 calculated by Mann–Whitney test. NGAL: neutrophil gelatinase-associated lipocalin; KIM-1: kidney injury molecule-1; ACR: albumin/creatinine ratio.

Figure 3. Discriminatory potency of biomarkers between the primarily inflammatory entities glomerulonephritis/vasculitis (IRD) vs. other entities of CKD (NIRD), illustrated by receiver-operating characteristic (ROC) curves of urinary (A) calprotectin, (B) NGAL, (C) KIM-1, and (D) ACR. Diagonal lines indicate differentiation by chance. NGAL: Neutrophil gelatinase-associated lipocalin; KIM-1: kidney injury molecule-1; ACR: albumin/creatinine ratio.