Low T3 syndrome and long-term mortality in chronic hemodialysis patients

Table 1 Baseline demographic, hemodynamic and clinical characteristics of low and normal freeT3 patient groups

Variable	Normal freeT3(n = 79)	Low freeT3(n = 35)	P value
Age	59.96 ± 14.74	66.84 ± 13.11	0.019
Female gender	18 (22.78%)	12 (34.28%)	0.237
BMI (kg/m2)	25.65 ± 2.92	26.49 ± 4.02	0.622
HD duration (mo)	66.42 ± 59.69	56.49 ± 41.08	0.302
HD morning shift	75 (94.93%)	32 (91.42%)	0.418
OL-HDF	22 (27.84%)	11 (31.42%)	0.484
CVC access	10 (12.65%)	9 (25.71%)	0.160
Kt/V	1.27 ± 0.39	1.29 ± 0.42	0.822
Smoking	16 (20.25%)	9 (25.71%)	0.606
History of CVD	24 (30.37%)	17(48.57%)	0.048
Diabetes	16 (20.25%)	16 (45.71%)	0.017
Hypertension	60 (75.94%)	23 (65.71%)	0.488
SBP (mmHg)	131.06 ± 19.94	130.50 ± 21.94	0.819
DBP (mmHg)	68.42 ± 13.87	71.22 ± 14.47	0.357

Values are expressed as means ± SD or numbers (%) as appropriate. BMI: Body mass index; CVC: Central venous catheter; CVD: Cardiovascular disease; DBP: Diastolic blood pressure; HD: Hemodialysis; OL- HDF: On-line hemodiafiltration; SBP: Systolic blood pressure.

Table 2 Baseline laboratory parameters of low and normal freeT3 patient groups

Variable	Normal freeT3(n = 79)	Low freeT3(n = 35)	P value
Creatinine (mg/dL)	9.50 ± 2.75	8.44 ± 2.35	0.041
Urea (mg/dL)	146.59 ± 36.73	140.33 ± 51.06	0.556
Cholesterol (mg/dL)	180.67 ± 47.3	175.8 ± 52.52	0.176
Triglycerides (mg/dL)	183.86 ± 94.69	171.20 ± 130.36	0.215
Hematocrit (%)	37.41 ± 3.74	36.63 ± 3.86	0.860
Hemoglobin (g/dL)	12.04 ± 1.33	11.52 ± 1.31	0.262
WBC (/mm3)	7.33 ± 2.20	7.61 ± 2.18	0.406
Albumin (g/dL)	3.99 ± 0.34	3.74 ± 0.497	0.002
TSH (μIU/mL)	2.77 ± 8.45	1.87 ± 1.02	0.354
FreeT4 (ng/dL)	1.13 ± 0.20	1.11 ± 0.3	0.170
IL-6 (pg/mL)	13.73 ± 13.29	16.49 ± 16.85	0.948
hsCRP (mg/dL)	1.56 ± 3.37	1.99 ± 2.73	0.156

Values are expressed as means ± SD or interquartile range as appropriate. hsCRP: High sensitive C-reactive protein; freeT4: Thyroxine; IL-6: Interleukin-6; TSH: Thyroid-stimulating hormone; WBC: White blood count.

Table 3 Demographic, clinical and laboratory significantly associated with survival in univariate Cox regression analyses

Variable	Spearman’s rho	P value
Age (yr)	0.345	< 0.001
Diabetes mellitus (yes/no)	0.199	0.050
Hemodialysis vintage (mo)	-0.435	0.017
Hemoglobin (g/dL)	-0.329	0.001
Hematocrit (%)	-0.270	0.007
Hypertension (yes/no)	0.275	0.006
Free T3 (pg/mL)	-0.257	0.011
Previous CVD events (yes/no)	0.305	0.002
hsCRP (mg/dL)	0.240	0.017
Creatinine (mg/dL)	-0.400	< 0.001

hsCRP: High sensitive C-reactive protein; freeT3: Free triiodothyronine; CVD: Cardiovascular disease.

Table 4 Adjusted and unadjusted relative risks of low freeT3 for all cause mortality

Variables	All cause mortality relative risks,(95%CI), P values
	Model 1(unadjusted)	Model 2(fully adjusted)
LowT3_1.8 (pg/mL)	1.89 (1.146-3.124) P = 0.013	1.61 (0.88-2.92) P = 0.115
Age (1 yr)	-	1.031 (1.00-1.05) P = 0.008
DM (yes)	-	1.22 (0.68-2.18) P = 0.50
History of CVD (yes)	-	1.878 (1.09-3.21) P = 0.021
Mean_Hb (1 g/dL)	-	0.561 (0.426-0.73) P = 0.000
hsCRP (0.1 mg/dL)	-	1.076 (0.91-1.27) P = 0.388
HD duration (1 mo)	-	0.990 (0.98-0.99) P = 0.004

DM: Diabetus mellitus; CVD: Cardiovascular disease; Hb: Hemoglobin; hsCRP: High sensitive C-reactive protein; HD: Hemodialysis.