Clinicopathological features and risk factors analysis of IgA nephropathy associated with acute kidney injury

Figures & data

Table 1. Demographic and clinical features at baseline between AKI and non-AKI group.

Characteristics	All (1512)	Non-AKI group (1367)	AKI group (145)	p Values
Age (year)	32.94 ± 10.34	32.74 ± 10.09	34.90 ± 12.36	0.017
Male (n, %)	699 (46.2)	607 (44.4)	92 (63.4)	<0.001
Preexisting impaired kidney function (Scr > 133 μmol/L) (n, %)	296 (19.6)	222 (16.2)	74 (51.0)	<0.001
Smoke (n, %)	118 (7.9)	99 (7.3)	19 (13.2)	0.021
Drinks (n, %)	44 (2.9)	38 (2.8)	6 (4.2)	0.305
Hypertension (n, %)	568 (37.6)	465 (34.0)	103 (71.0)	<0.001
Malignant hypertension (n, %)	10 (0.7)	4 (0.3)	6 (4.1)	<0.001
Macroscopic hematuria (n, %)	334 (22.1)	318 (23.3)	16 (11.0)	<0.001
SBP (mmHg)	127.60 ± 19.71	125.92 ± 18.34	143.39 ± 24.68	<0.001
DBP(mmHg)	80.62 ± 13.65	79.65 ± 13.03	89.76 ± 15.80	<0.001
Baseline Scr (μmol/L)	83 (63,115)	79 (61,106.75)	135 (89.6,220.15)	<0.001
Peak Scr when AKI attack (μmol/L)	NA	NA	351 (194, 685.5)	<0.001
Proteinuria (g/day)	1.13 ± 1.41	1.03 ± 1.32	2.02 ± 1.81	<0.001
<1 g/day (n, %)	950 (66.2)	903 (69.7)	47 (33.3)	<0.001
1∼3 g/day (n, %)	349 (24.3)	291 (22.50)	58 (41.1)	<0.001
>3 g/day (n, %)	137 (9.5)	101 (7.8)	36 (25.5)	<0.001
Hb (g/L)	126.12 ± 21.48	127.24 ± 20.46	115.52 ± 27.30	<0.001
Anemia (n, %)	333 (22.0)	265(19.4)	68 (46.9)	<0.001
UA (μmol/L)	367.53 ± 126.93	355.87 ± 120.00	477.75 ± 137.77	<0.001
TP (g/L)	65.12 ± 9.38	65.65 ± 9.16	60.16 ± 10.01	<0.001
ALB (g/L)	38.34 ± 6.43	38.72 ± 6.28	34.77 ± 6.75	<0.001
Chol (mmol/L)	5.37 ± 1.81	5.31 ± 1.77	5.96 ± 2.06	<0.001
TG (mmol/L)	1.64 ± 1.43	1.58 ± 1.42	2.17 ± 1.42	<0.001
IgA (g/L)	2.96 ± 0.97	2.98 ± 1.00	2.79 ± 1.02	0.033
ACEI/ARB treatment (n, %)	1140 (75.7)	1046 (76.7)	94 (65.7)	0.005
Diuretic (n, %)	25 (1.7)	17 (1.3)	8 (5.7)	0.001
Oral corticosteroid (n, %)	436 (29.0)	363 (26.7)	73 (51.0)	<0.001
MP impulse treatment (n, %)	52 (4.1)	40 (3.5)	12 (9.9)	0.002
Immunosuppressant (n, %)	37 (2.5)	32 (2.4)	5 (3.5)	0.389

Notes: SBP: systolic blood pressure; DBP: diastolic blood pressure; Scr: serum creatinine; Hb: hemoglobin; UA: uric acid; TP: total serum protein; ALB: albumin; Chol: cholesterol; TG: triglycerol; IgA: immunoglobulin A; MP: methylprednisolone; ACEI: Angiotensin-Converting Enzyme Inhibitor; ARB: Angiotensin II receptor blockage; immunosuppressant: including cyclosporine A: tacrolimus: mycophenolate mofetil: and cyclophosphamide; NA: lack of data. Values are expressed as mean ± SD; categorical variables are expressed in percentage.

Table 2. Comparison of pathological features between AKI and non-AKI group.

Variables	All (1512)	Non-AKI group (1367)	AKI group (145)	p Values
Glomeruli with GS (%)	12.00 (2.52, 33.33)	10.70 (0,29.4)	41.40 (14.37, 70.12)	<0.001
Glomeruli with crescents (n, %)^a	0.00 (0,7.1)	0.00 (0, 6.70)	4.0 (0, 10.90)	<0.001
Cellular crescent (n, %)				0.004
<25%	552 (84.5)	495 (86.1)	57 (73.1)
25–50%	32 (4.9)	23 (4.0)	9 (11.5)
50–100%	69 (10.6)	57 (9.9)	12 (15.4)
Fibrocellular crescent (n, %)				0.001
<25%	461 (70.6)	420 (73.0)	41 (52.6)
25–50%	53 (8.1)	43 (7.5)	10 (12.8)
50–100%	139 (21.3)	112 (19.5)	27 (34.6)
Fibrous crescent (n, %)				0.915
<25%	547 (83.8)	481 (83.7)	66 (84.6)
25–50%	22 (3.4)	20 (3.5)	2 (2.6)
50–100%	84 (12.9)	74 (12.9)	10 (12.8)
Mesangial proliferation, M1 (n, %)	1360 (89.9)	1238 (90.6)	122 (84.1)	0.020
Endothelial cell proliferation, E1 (n, %)	277 (18.3)	253 (18.5)	24 (16.6)	0.652
Glomeruli with SS, S1 (n, %)	691 (45.7)	606 (44.3)	85 (58.6)	0.001
Tubular atrophy/interstitial fibrosis, T (n, %)				<0.001
T0	1158 (76.6)	1092 (79.9)	66 (45.5)
T1	275 (18.2)	226 (16.5)	49 (33.8)
T2	79 (5.2)	49 (3.6)	30 (20.7)
Interstitial cell infiltration (n, %)				<0.001
<25%	1210 (80.0)	1140 (83.4)	70 (48.3)
25–50%	241 (15.9)	193 (14.1)	48 (33.1)
50–100%	61 (4.0)	34 (2.5)	27 (18.6)
Tuft necrosis (n, %)	123 (8.1)	115 (8.4)	8 (5.5)	0.265

Notes: GS: global sclerosis; SS: segmental sclerosis.

^aAll kinds of crescents (cellular, fibrocellular, and fibrous crescent) were calculated; Variables (Glomeruli with GS, crescents) are expressed as median; other variables are expressed in percentages.

Table 3. Possible special pathological changes involved in IgAN associated with AKI.

Possible pathological spectrum	Percentage
Crescentic glomerulonephritis	2 (1.4%)
Acute tubular injury/necrosis	6 (4.1%)
Acute tubulointerstitial nephritis	14 (9.7%)
Malignant hypertensive renal lesion	6 (4.1%)
Unclassified^a	117 (80.7%)

^aIncluding different degree of chronic sclerosing glomerulonephritis, or mild mesangioproliferative type with/without segmental sclerosis/global sclerosis/fibrous crescents/hypertensive renal lesion, or minimal change type as well as focal segmental sclerosing type.

Table 4. Risk factors of AKI in IgAN patients with univariate and multivariate analysis.

	Univariate analysis			Multivariate analysis
	Variable	OR	95% CI	p	OR	95% CI	p
Age (year)/10	1.21	(1.04, 1.42)	0.017	1.27	(1.07,1.51)	0.007
Gender (male)	2.17	(1.53, 3.10)	<0.001	1.51	(1.00,2.27)	0.048
Preexisting impaired kidney function (Scr > 133umol/L)	5.38	(3.77, 7.67)	<0.001
Malignant hypertension	14.71	(4.10, 52.75)	<0.001	8.47	(2.02,35.54)	0.003
Macroscopic hematuria	0.41	(0.24,0.70)	0.001
Proteinuria (g/day)	1.39	(1.27, 1.52)	<0.001	1.27	(1.14, 1.41)	<0.001
Cellular crescent	2.29	(1.38, 3.81)	0.001	2.03	(1.13,3.64)	0.018
Fibrocellular crescent	2.69	(1.82, 3.98)	<0.001	2.09	(1.34, 3.26)	0.001
Interstitial cell Infiltration ≥50%	8.97	(5.23, 15.38)	<0.001
Glomerulosclerosis ≥50%	4.97	(3.46, 7.15)	<0.001	2.02	(1.16, 3.51)	0.013
Tubular atrophy ≥50%	8.94	(5.54, 14.43)	<0.001
Interstitial fibrosis ≥50%	7.02	(4.29, 11.49)	<0.001

Notes: Variables with p < 0.05 in univariate analysis for a relationship with AKI were entered into multivariate analysis as covariates.