Risk factors and renal outcomes of AKI in children with secondary steroid-resistant nephrotic syndrome

Figures & data

Figure 1. Cause of acute kidney injury in hospitalized patients with secondary SRNS.

Table 1. Patient characteristics of hospitalized children with secondary SRNS.

Characteristics	AKI (n = 67)	Non-AKI (n = 105)	P Value
Sex, male, n (%)	48 (71.6%)	73 (69.5%)	0.767
Age at onset (years)	4.4 (3.1, 6.7)	3.7 (1.8, 5.6)	0.036
Age at admission (years)	7.7 (5.6, 10.8)	7.3 (5.1, 9.8)	0.352
Durations before SRNS (weeks)	24.3 (15.3, 68.1)	26.6 (15.1, 71.0)	0.571
Frequency of relapses before secondary SRNS (n, %)			0.813
Once	31 (46.3%)	47 (44.8%)
Frequently relapsing	33 (49.3%)	55 (52.4%)
Infrequently relapsing	3 (4.5%)	3 (2.9%)
Laboratory examination
Serum albumin (g/L)	15.6 (11.3, 24)	16.0 (13.1, 22.2)	0.544
Urea nitrogen (mmol/L)	5.9 (4.1, 10.0)	5.1 (3.7, 7.0)	0.018
Baseline creatinine (umol/L)	32.0 (26.0, 38.0)	28.0 (22.0, 35.0)	0.041
Uric acid (umol/L)	446.0 (340.0, 567.0)	401.0 (303.0, 496.0)	0.016
24-h urinary protein (g)	4.14 (2.9, 6.5)	2.5 (1.3, 5.3)	0.000
Kidney biopsy			0.009
MCD	19 (28.4%)	57 (54.3%)
FSGS	24 (35.8%)	21 (20.0%)
MesP GN, others	9 (13.4%)	10 (9.5%)
Not done	15 (22.4%)	17 (16.2%)
Nephrotoxic drug	45 (67.2%)	55 (52.4%)	0.055
Antibiotics	9 (13.4%)	4 (3.8%)	0.042
CNI	38 (56.7%)	49 (46.7%)	0.199
ACE-I/ARB	6 (9.0%)	4 (3.8%)	0.284
Infection	54 (80.6%)	56 (53.3%)	0.000
Length of hospital stay (days)	30 (23, 43)	21 (14, 28)	0.000

Secondary SRNS: secondary steroid-resistant nephrotic syndrome; AKI: acute kidney injury, MCD: minimal change disease; FSGS: focal segmental glomerulosclerosis; MesP GN: mesangial proliferative glomerulonephritis; CNI: calcineurin inhibitor; ACE-I: angiotensin-converting enzymeinhibitor; ARB: angiotensin-receptor blocker; frequent relapsing NS was defined as ≥2 relapses per 6 months within 6 months of NS onset or ≥4 relapses per year in any subsequent 12-month period, while infrequent relapsing NS was defined as <2 relapses per 6 months or <4 relapses per year.

Table 2. Factors associated with AKI in hospitalized children with secondary SRNS.

Variables	Univariate		Multivariate
	OR (95% CI)	P Value	OR (95% CI)	P Value
Age at onset (years)	1.136 (1.015–1.273)	0.027	1.180 (1.032–1.349)	0.015
Serum albumin (g/L)	0.964(1.033–1.033)	0.998
Urea nitrogen (mmol/L)	1.088 (1.013–1.168)	0.021	1.051 (0.966–1.144)	0.250
Uric acid (umol/L)	1.003 (1.001–1.005)	0.006	1.003 (1.000–1.006)	0.031
24-h urinary protein (g)	1.144(1.028–1.273)	0.014	1.117 (0.995–1.253)	0.061
Infection	3.635 (1.775–7.442)	0.000	5.287 (2.349–11.899)	0.000
Use of CNI	1.498 (0.808–2.775)	0.199

Secondary SRNS: secondary steroid-resistant nephrotic syndrome; AKI: acute kidney injury, CI: confidence interval; OR: odds ratio; CNI: calcineurin inhibitor.

Figure 2. Kaplan–Meier survival curves for renal outcome in AKI and non-AKI hospitalized children with secondary SRNS.

Figure 3. Kaplan–Meier survival curves for renal outcome in more than one AKI episode and one AKI episode hospitalized children with secondary SRNS.