Glomerular and tubular functions in children with different forms of beta thalassemia

Figures & data

Table 1. According to the groups, demographic and basic laboratory data.

	Group 1 (TM) N = 49	Group 2 (TI) N = 18	Group 3 (TMin) N = 51	Group 4 (controls) N = 51
Age (year)	10.9 ± 4.2	9.5 ± 4.0	9.6 ± 4.0	9.0 ± 4.0
Gender (female/male)	26/23	7/11	23/28	22/29
Hemoglobin (g/dL)	9.0 ± 0.9	8.4 ± 1.5	11.0 ± 0.7	13.2 ± 0.8
Ferritin (ng/mL)	1925.1 ± 1100.2	773.8 ± 340.3	52.1 ± 35.7	47.5 ± 34.3
Creatinine (mg/dL)	0.43 ± 0.07	0.37 ± 0.11	0.44 ± 0.11	0.42 ± 0.10

Notes: TM, thalassemia major; TI, thalassemia intermedia; TMin: thalassemia minor.

Table 2. Comparison of renal tubular functions among groups.

					p-Values
	Group 1—TM (N = 49)	Group 2—TI (N = 18)	Group 3—TMin (N = 51)	Group 4—Controls (N = 51)	Group 1–Group 4	Group 2–Group 4	Group 3–Group 4	Group 1–Group 2	Group 1–Group 3	Group 2–Group 3
FENa (%)	0.50 ± 0.30	0.70 ± 0.40	0.40 ± 0.40	0.30 ± 0.30	0.009	0.0001	ND	ND	0.0001	0.0001
Urinary excretion of uric acid (mg/dL GFR)	0.50 ± 0.20	0.50 ± 0.30	0.30 ± 0.10	0.30 ± 0.10	0.0001	0.0001	ND	ND	0.0001	0.0001
alpha-1M (mcg/mL)	25.00 ± 7.70	25.00 ± 9.50	12.20 ± 9.10	11.10 ± 8.90	0.0001	0.0001	ND	ND	0.0001	0.0001
RBP (mcg/mL)	0.06 ± 0.04	0.06 ± 0.04	0.05 ± 0.03	0.04 ± 0.02	0.022	ND	ND	ND	ND	ND
beta-2 m (mcg/mL)	21.50 ± 37.90	16.50 ± 34.20	7.70 ± 5.10	5.90 ± 4.60	0.013	ND	ND	ND	0.023	ND
Urinary calcium/ creatinine (mg/mg)	0.10 ± 0.10	0.20 ± 0.10	0.10 ± 0.10	0.10 ± 0.10	0.007	ND	ND	ND	ND	ND
TPR (%)	95.20 ± 2.40	94.00 ± 4.70	94.50 ± 3.20	94.60 ± 3.20	ND	ND	ND	ND	ND	ND

Notes: TM, thalassemia major; TI, thalassemia intermedia; TMin, thalassemia minor; FENa (%), fractioned sodium excretion; alpha-1M, alpha-1 macroglobulin; RBP, retinol-binding protein; beta-2 m, beta-2 microglobulin; TPR, tubular reabsorption of phosphorus; ND, no difference.

Table 3. Comparison of renal glomerular functions among groups.

					p-Values
	Group 1—TM (N = 49)	Group 2—TI (N = 18)	Group 3—TMin (N = 51)	Group 4—Controls (N = 51)	Group 1–Group 4	Group 2–Group 4	Group 3–Group 4	Group 1–Group 2	Group 1–Group 3	Group 2–Group 3
Cystatin C (ng/mL)	3.70 ± 0.90	4.10 ± 0.90	3.20 ± 0.60	2.60 ± 0.90	0.0001	0.0001	0.003	ND	0.016	0.001
Urinary protein/creatinine (mg/mg)	0.20 ± 0.10	0.20 ± 0.10	0.10 ± 0.10	0.10 ± 0.00	0.01	0.0001	ND	ND	0.012	0.0001
e-GFR (mL/min/1.73m2)	121.40 ± 10.70	123.20 ± 15.30	117.70 ± 8.20	120.30 ± 11.40	ND	ND	ND	ND	ND	ND

Notes: TM, thalassemia major; TI, thalassemia intermedia; TMin, thalassemia minor; e-GFR, estimated glomerular filtration rate; ND, no difference.

Table 4. Correlation between ferritin and glomerular and tubular functional parameters.

Variables	R (neg)	p-Value
FENa (%)	0.229	0.003
RBP (mcg/mL)	0.185	0.036
Alpha-1M (mcg/mL)	0.470	0.0001
Beta-2 m (mcg/mL)	0.251	0.001
Cystatin-C (ng/mL)	0.293	0.0001
Protein/creatinine	0.187	0.02

Notes: R, correlation coefficient, FENa (%), fractioned sodium excretion; RBP, retinol-binding protein; alpha-1M, alpha-1 macroglobulin; beta-2 m, beta-2 microglobulin.