Analysis of the incidence and influencing factors of hyponatremia before 131I treatment of differentiated thyroid carcinoma

Table 3 Baseline characteristics of the hyponatremia group and non-hyponatremia group before ¹³¹I treatment

Items	Hyponatremia group	Non-hyponatremia group	P value
Sex (n, %)			0.008
Male	13 (56.5)	270 (30.7)
Female	10 (43.5)	610 (69.3)
Age (yr)	50.5 ± 14.2	43.6 ± 12.7	0.01
Body mass index (kg/m2)	22.2 ± 3.3	23.1 ± 4.3	0.348
Systolic blood pressure (mmHg)	129.9 ± 21.1	124.5 ± 18.1	0.161
History of ACEI or ARB (n, %)			0.42
Yes	3 (13.1)	69 (7.8)
No	20 (86.9)	811 (2.2)
History of diuretics (n, %)			0.015
Yes	4 (17.4)	35 (4.1)
No	19 (82.6)	845 (95.9)
Distant metastasis (n, %)			0.014
Yes	6 (26.1)	77 (8.8)
No	17 (73.9)	803 (91.2)
Hemoglobin (g/L)	141.1 ± 19.5	144.2 ± 18.4	0.52
Fasting blood glucose (mmol/L)	5.2 (4.6, 7.2)	5.1 (4.8, 5.6)	0.267
Pre-operation serum sodium (mmol/L)	139.5 ± 2.6	141.3 ± 2.3	0.001
Pre-131I therapy serum sodium (mmol/L)	133.6 ± 1.9	140.6 ± 1.8	0.001
Serum potassium (mmol/L)	4.3 ± 0.3	4.2 ± 0.3	0.462
Serum calcium (mmol/L)	2.3 ± 0.1	2.2 ± 0.1	0.062
Blood urea nitrogen (mmol/L)	4.7 ± 2.1	3.8 ± 1.2	0.043
Serum creatinine (µmol/L)	78.7 ± 13.3	74.4 ± 16.4	0.271
Urinary iodine (µg/L)	83.1 (52.9, 100.3)	93.1 (54.5, 203.1)	0.037
Total protein (g/L)	77.1 ± 5.9	76.9 ± 4.4	0.865
Albumin (g/L)	46.6 ± 4.2	47.9 ± 2.8	0.155
Globulin (g/L)	30.5 ± 4.1	29.1 ± 3.7	0.077
eGFR (mL/min m2)	81.8 ± 11.4	88.8 ± 15.3	0.029
TSH (mIU/L)	99.5 ± 28.5	130.6 ± 59.4	0.001
FT3 (pmol/L)	2.8 ± 0.4	2.9 ± 0.6	0.594
FT4 (pmol/L)	2.1 ± 1.2	1.8 ± 1.2	0.27

DM: Diabetes mellitus; ACEI: Angiotensin-converting enzyme inhibitor; ARB: angiotensin receptor blocker.