Differences in new-onset IgA nephropathy between young adults and the elderly

Figures & data

TABLE 1.  Reasons for renal biopsy in young adults and the elderly with IgA nephropathy

	Young adults group (n = 82)	Elderly group (n = 17)
Acute renal failure + hematuria + proteinuria	10 (12.2%)	9 (52.9%)
Hematuria + nephrotic range proteinuria	19 (23.2%)	7 (41.2%)
Hematuria + non-nephrotic range proteinuria	44 (53.7%)	0 (0%)
Isolated hematuria	9 (11.0%)	1 (5.9%)

TABLE 2.  Comparison of clinical and histological parameters of IgA nephropathy between young adults and the elderly

Variables	Young adults group (n = 82)^c	Elderly group (n = 17)^c	p-Value
Clinical parameters
Age (years)	30.3 ± 10.2	71.9 ± 4.5
Gender (male/female)	40/42	11/6	0.291^b
Hypertension	25 (30.5)	15 (88.2)	<0.001^b
Hematuria (score)	2.3 ± 1.5	2.1 ± 1.8	0.571^a
Macroscopic hematuria	16 (19.5)	3 (17.6)	1.000^b
Proteinuria (g/24 h)	2.6 ± 4.0	5.1 ± 4.2	0.009^a
Proteinuria ≥ 3 g/24 h	22 (26.8)	12 (70.6)	0.001^b
Acute renal failure	10 (12.2)	9 (52.9)	<0.001^b
Histological parameters
Mesangial hypercellularity (score)	1.5 ± 0.8	1.6 ± 0.8	0.711^a
Globally sclerotic glomeruli (%)	9.3 ± 11.1	20.9 ± 14.8	<0.001^a
Segmental glomerular sclerosis	14 (17.1)	1 (5.9)	0.457^b
Endocapillary proliferation	1 (1.2)	0 (0)	1.000^b
Glomerular neutrophil infiltration	1 (1.2)	2 (11.8)	0.075^b
Glomerular crescents	18 (22.0)	4 (23.5)	1.000^b
Tubular atrophy (score)	0.9 ± 0.4	0.9 ± 0.2	0.562^a
Interstitial fibrosis (score)	0.3 ± 0.5	0.5 ± 0.5	0.224^a
Interstitial infiltration (score)	0.7 ± 0.8	1.1 ± 0.8	0.112^a
IgA intensity (score)	1.6 ± 0.5	1.7 ± 0.5	0.455^a
IgG positive staining	45 (54.9)	13 (76.0)	0.114^b
IgM positive staining	47 (57.3)	11 (64.7)	0.787^b
C3 positive staining	63 (76.8)	12 (70.6)	0.551^b
C1q positive staining	5 (6.1)	3 (18.0)	0.136^b

Notes: *p-Value < 0.05.

^aData were analyzed by Mann–Whitney U-test.

^bData were analyzed by Fisher's exact test.

^cMean ± SD or number (%).

TABLE 3.  Comparison of clinical and histological parameters of acute renal failure in IgA nephropathy between young adults and the elderly

Variables	Young adults group (n = 10)^c	Elderly group (n = 9)^c	p-Value
Clinical parameters
Age (years)	38.2 ± 11.0	74.0 ± 4.8
Gender (male/female)	6/4	8/1	0.303^b
Hematuria (score)	3.1 ± 1.5	3.2 ± 1.4	0.930^a
Proteinuria (g/24 h)	4.0 ± 6.5	3.1 ± 2.6	0.659^a
Serum creatinine at biopsy (mg/dl)	5.4 ± 3.2	7.8 ± 5.2	0.310^a
Dialysis support requirement	5 (50.0)	5 (55.6)	1.000^b
Intercurrent disease	3 (30.0)	8 (88.9)	0.020^b
Histological parameters
Globally sclerotic glomeruli (%)	9.5 ± 8.8	22.3 ± 15.7	0.077^a
Glomeruli with crescents	9 (90.0)	4 (44.4)	0.057^b
Crescents in >30% of glomeruli	9 (90.0)	3 (33.3)	0.020^b
Crescents in >50% of glomeruli	5 (50.0)	2 (22.2)	0.350^b
% Glomeruli affected by crescent	48.9 ± 25.5	18.2 ± 27.2	0.027^a
Acute tubular injury	1 (11.1)	6 (66.7)	0.020^b
Interstitial infiltration (2+ or 3+)	3 (30.0)	2 (22.2)	1.000^b
Outcome
Follow-up (months)	18.8 ± 8.5	8.6 ± 5.5
Death	0 (0)	4 (44.4)	0.033^b
Complete remission	3 (30.0)	2 (22.2)	1.000^b
Partial remission	2 (20.0)	1 (11.1)	1.000^b
End-stage renal disease	5 (50.0)	2 (22.2)	0.350^b

Notes: *p-Value < 0.05.

^aData were analyzed by Mann–Whitney U-test.

^bData were analyzed by Fisher's exact test.

^cMean ± SD or number (%).

TABLE 4.  Intercurrent diseases in cases of IgA nephropathy with acute renal failure

Young adults group (n = 3)	Elderly group (n = 8)
Bacteremia (2)	Bacteremia (4)
MRSA (infected surgical wound)	MRSA (central line infection)
MSSA (septic arthritis of hip)	MSSA (osteomyelitis of spine)
Autoimmune hemolysis (1)	Klebsiella pneumoniae (septic arthritis of knee)
	Acinetobacter baumannii (unknown origin)
	Pneumonia (3)
	Klebsiella ozaenae
	Pseudomonas aeruginosa
	MRSA
	Malignancy (1)
	Small cell carcinoma of lung

Notes: MRSA, methicillin-resistant Staphylococcus aureus; MSSA, methicillin-sensitive Staphylococcus aureus.

TABLE 5.  Comparison of clinical and histological parameters of nephrotic IgA nephropathy between young adults and the elderly

Variables	Young adults group (n = 19)^c	Elderly group (n = 7)^c	p-Value
Clinical parameters
Age (years)	26.9 ± 10.3	70.1 ± 2.6
Gender (male/female)	7/12	3/4	1.000^b
Hypertension	13 (68.4)	6 (85.7)	0.629^b
Hematuria (score)	2.1 ± 1.6	1.0 ± 1.4	0.148^a
Proteinuria (g/24 h)	6.5 ± 5.0	8.5 ± 3.7	0.099^a
Serum creatinine at biopsy (mg/dL)	1.0 ± 0.2	1.0 ± 0.3	0.817^a
Histological parameters
Globally sclerotic glomeruli (%)	7.0 ± 11.6	21.3 ± 14.5	0.009^a
Mesangial cellularity (score)	1.6 ± 0.8	1.4 ± 0.5	0.603^a
Segmental glomerulosclerosis	5 (26.3)	1 (14.3)	1.000^b
Outcome
	(n = 13)	(n = 6)
Follow-up (months)	33.3 ± 9.1	20.1 ± 8.6
Complete remission	5 (38.5)	3 (50.0)	1.000^b
Partial remission	2 (15.4)	1 (16.7)	1.000^b
Not remission with preserved renal function	2 (15.4)	1 (16.7)	1.000^b
Renal insufficiency	2 (15.4)	0 (0)	1.000^b
End-stage renal disease	2 (15.4)	1 (16.7)	1.000^b

Notes: *p-Value < 0.05.

^aData were analyzed by Mann–Whitney U-test.

^bData were analyzed by Fisher's exact test.

^cMean ± SD or number (%).