Baseline clinical and laboratory characteristics
The baseline demographic and clinical characteristics of enrolled children are shown in Table 1. There was no statistically significant difference in mean age, gender ratio, and BMI between the euthyroid and ESS groups. White blood cell count (WBC), plasma glucose (PG), beta-hydroxybutyric acid (β-HB), triglyceride (TG), anion gap (AG), and glycosylated hemoglobin (HbA1c) levels were significantly higher in the ESS group than in the euthyroid group, whereas serum HCO3-, albumin (ALB), and prealbumin (PA) levels were significantly lower in the ESS group than in the euthyroid group (p <0.05).
Table 1. Baseline clinical and laboratory characteristics in DKA/DK children
Variables
|
Thyroid function
|
Z/T/c2
|
P
|
Euthyroidism
|
ESS
|
Gender (male/female)
|
50/38
|
59/47
|
0.03
|
0.871
|
Age (years)
|
7.16±4.24
|
7.42±4.27
|
0.416
|
0.678
|
BMI (kg/m2)
|
16.93±3.19
|
15.80±3.07
|
-1.589
|
0.116
|
WBC (×109/L)
|
7.25 (6.15~9.82)
|
10.72 (7.82~16.9)
|
-5.316
|
<0.001*
|
PG (mmol/L)
|
19.13 (14.97~27.8)
|
21.77 (16.89~29.46)
|
-3.222
|
0.001*
|
BUN (mmol/L)
|
5.35 (4.48~6.35)
|
4.95 (3.93~6.75)
|
-0.372
|
0.71
|
Cr (umol/L)
|
31.3 (23.55~48.63)
|
34.05 (25.15~45.64)
|
-0.765
|
0.444
|
β-HB (mmol/L)
|
2.92 (1.61~5.22)
|
6.52 (4.28~8.46)
|
-7.375
|
<0.001*
|
K+ (mmol/L)
|
4.25 (3.8~4.6)
|
4.2 (3.5~4.63)
|
-1.403
|
0.161
|
Na+ (mmol/L)
|
133.42±4.72
|
131.02±5.28
|
3.309
|
0.001*
|
Corrected Na+ (mmol/L)
|
139 (137.2~141.7)
|
138.6 (134~140.6)
|
-1.405
|
0.16
|
Cl- (mmol/L)
|
99.3 (96~103)
|
101 (96~106.15)
|
-1.256
|
0.209
|
HCO3- (mmol/L)
|
19.15 (16.4~21.9)
|
9.55 (6.63~14.75)
|
-7.946
|
<0.001*
|
OSM (mOsm/L)
|
284.39 (279~289.03)
|
280.02 (272.05~286.49)
|
-0.978
|
0.328
|
AG (mmol/L)
|
19.2 (17.2~22.15)
|
22.97 (19.65~27.53)
|
-4.857
|
<0.001*
|
ALT (U/L)
|
14 (12~18.25)
|
14 (10~17.75)
|
-0.746
|
0.456
|
PA (mg/L)
|
123.93 (99.39~151)
|
93.88 (71.97~123.7)
|
-5.748
|
<0.001*
|
ALB (g/L)
|
39.76±4.58
|
37.58±5.53
|
2.809
|
0.006*
|
GLO (g/L)
|
23.1(20.08~26.78)
|
22.4 (19.3~25.95)
|
-1.594
|
0.111
|
TC (mmol/L)
|
4.4(3.77~5.06)
|
4.14(3.67~5.24)
|
-0.267
|
0.789
|
HDL (mmol/L)
|
1.15(0.96~1.44)
|
1.13(0.94~1.36)
|
-0.769
|
0.442
|
LDL (mmol/L)
|
2.51(2.06~2.99)
|
2.54(1.94~3.11)
|
-0.594
|
0.553
|
TG (mmol/L)
|
0.97(0.69~1.31)
|
1.34(0.91~2.19)
|
-3.724
|
<0.001*
|
HbA1c (%)
|
11.42±2.49
|
12.62±2.15
|
-3.593
|
<0.001*
|
C-p (ng/ml)
|
0.19(0.09~0.46)
|
0.19(0~0.34)
|
-1.294
|
0.196
|
Abbreviations: β-HB, beta-hydroxybutyric acid; ALB, albumin; GLO, globulin; HbA1c, glycosylated hemoglobin; HDL, high density lipoprotein; LDL, low density lipoprotein; OSM, osmolarity; AG, anion gap; PA, prealbumin; PG, plasma glucose; TC, total cholesterol; TG, triglyceride; WBC, white blood cell count; BMI, body mass index; BUN, serum urea nitrogen; Cr, creatinine; ALT, alanine aminotransferase; C-p, C-peptide
*P<0.05 ESS vs. euthyroidism
Correlating and independent influencing factors of FT3
FT3 levels positively correlated with levels of serum corrected Na+, HCO3-, PA, K+, ALB, GLO, and HDL but negatively correlated with WBC, PG, β-HB, AG, TG, and HbA1c. There was no significant correlation between levels of FT3 and BUN, Cr, Cl-, OSM, ALT, TC, LDL, and C-p (P>0.05, data not shown). Variables showing significant correlation were subjected to multivariate linear regression analysis, which showed that β-HB, HCO3-, AG, PA, and HbA1c independently affected FT3 levels (Table 2). The correlations between these independent variables and FT3 are shown in the scatter plot on Figure 1 (r=-0.642, 0.681, -0.377, 0.581, -0.309, respectively; P<0.01)
Table 2. Correlating factors of FT3 in DKA/DK children
Variables
|
B SD
|
Beta
|
T
|
P
|
WBC
|
-0.016
|
0.011
|
-0.092
|
-1.417
|
0.159
|
PG
|
-0.001
|
0.01
|
-0.007
|
-0.122
|
0.903
|
β-HB
|
-0.151
|
0.048
|
-0.331
|
-3.116
|
0.002*
|
Corrected Na+
|
-0.006
|
0.017
|
-0.02
|
-0.351
|
0.726
|
K+
|
-0.013
|
0.102
|
-0.008
|
-0.128
|
0.898
|
HCO3-
|
0.067
|
0.019
|
0.342
|
3.603
|
<0.001*
|
AG
|
0.042
|
0.02
|
0.197
|
2.161
|
0.033*
|
PA
|
0.011
|
0.003
|
0.3
|
3.961
|
<0.001*
|
ALB
|
0.02
|
0.02
|
0.076
|
1.04
|
0.3
|
GLO
|
-0.013
|
0.016
|
-0.049
|
-0.815
|
0.417
|
HDL
|
0.113
|
0.261
|
0.028
|
0.434
|
0.665
|
TG
|
-0.069
|
0.067
|
-0.064
|
-1.031
|
0.305
|
HbA1c
|
-0.07
|
0.034
|
-0.121
|
-2.082
|
0.039*
|
*P<0.05
Correlating and independent influencing factors of FT4
FT4 levels positively correlated with serum levels of corrected Na+, HCO3-, PA, ALB, GLO, and HDL but negatively correlated with WBC, PG, β-HB, AG, Cl-, TG, and HbA1c. There was no significant correlation between FT4 levels and BUN, Cr, K+, OSM, ALT, TC, LDL, and C-p (P>0.05, data not shown). Variables showing significant correlation were subjected to multivariate linear regression analysis, which showed that β-HB, HCO3-, and ALB significantly affected FT4 levels (Table 3). The correlations between these variables and FT4 levels are shown in the scatter plot on Figure 2 (r=-0.489, 0.338, 0.529, respectively; P<0.01).
Table 3 Correlating factors of FT4 in DKA/DK children
Variables
|
B SD
|
Beta
|
T
|
P
|
WBC
|
-0.009
|
0.045
|
-0.017
|
-0.199
|
0.843
|
PG
|
-0.003
|
0.039
|
0.007
|
0.086
|
0.931
|
β-HB
|
-0.434
|
0.196
|
-0.303
|
-2.216
|
0.028*
|
Corrected Na+
|
0.095
|
0.077
|
0.103
|
1.237
|
0.218
|
HCO3-
|
0.156
|
0.084
|
0.253
|
1.849
|
0.047*
|
AG
|
0.07
|
0.082
|
0.103
|
0.848
|
0.398
|
PA
|
0.013
|
0.011
|
0.119
|
1.219
|
0.225
|
TG
|
0.135
|
0.27
|
0.04
|
0.501
|
0.617
|
HbA1c
|
0.036
|
0.136
|
0.02
|
0.268
|
0.789
|
Cl-
|
-0.07
|
0.039
|
-0.158
|
-1.782
|
0.077
|
ALB
|
0.164
|
0.078
|
0.193
|
2.093
|
0.038*
|
GLO
|
-0.026
|
0.064
|
-0.032
|
-0.413
|
0.681
|
HDL
|
1.338
|
1.053
|
0.107
|
1.271
|
0.206
|
*P<0.05
Correlating and independent influencing factors of TSH
TSH showed positive correlation with levels of corrected Na +, HCO3-, OSM, TC, and LDL but negative correlation with WBC, β-HB, and BUN. There was no significant correlation between TSH and levels of PG, K+, Cl-, Cr, ALT, AG, PA, TG, HbA1c, ALB, GLO, HDL, and C-p (P>0.05), data not shown. Variables which showed significant correlation were subjected to multivariate linear regression analysis, which revealed that only serum HCO3- levels had an independent and significant effect on TSH levels (Table 4). The correlations between serum HCO3- and TSH levels are shown in the scatter plot on Figure 3 (r=-0.28, P<0.01).
Table 4 Correlating factors of TSH in DKA/DK children
Variables
|
B SD
|
Beta
|
T
|
P
|
WBC
|
-0.009
|
0.018
|
-0.05
|
-0.495
|
0.621
|
β-HB
|
0.037
|
0.059
|
0.08
|
0.632
|
0.529
|
corrected Na+
|
0.016
|
0.028
|
0.052
|
0.563
|
0.575
|
HCO3-
|
0.071
|
0.025
|
0.362
|
2.834
|
0.005*
|
BUN
|
-0.025
|
0.052
|
-0.042
|
-0.493
|
0.623
|
OSM
|
0.005
|
0.005
|
0.079
|
0.876
|
0.383
|
TC
|
0.134
|
0.262
|
0.101
|
0.511
|
0.61
|
LDL
|
0.1
|
0.35
|
0.058
|
0.284
|
0.777
|
*P<0.05
Logistic regression of adjudicated thyroid function group with metabolic covariates
Logistic regression model analysis used the thyroid function subgroup (euthyroid or ESS group) as a non-parametric dependent variable and significantly correlated variables in Table 1 as parametric independent variables. As shown in Table 5, serum HCO3- levels was the only factor independently and significantly associated with thyroid function group adjudication (OR=0.845, P=0.004, 95%CI=0.752-0.949).
Table 5. Logistic regression on the predictors of deranged thyroid function in DKA/DK patients
Variables
|
B
|
p-value
|
Wald
|
Adjusted p-value
|
OR
|
95% C.I. for OR
|
Inferior
|
Superior
|
WBC
|
0.127
|
0.062
|
4.227
|
0.050
|
1.136
|
1.006
|
1.283
|
PG
|
0
|
0.028
|
0
|
0.996
|
1
|
0.946
|
1.057
|
β-HB
|
0.14
|
0.145
|
0.937
|
0.333
|
1.15
|
0.866
|
1.558
|
HCO3-
|
-0.168
|
0.059
|
8.072
|
0.004*
|
0.845
|
0.752
|
0.949
|
AG
|
-0.02
|
0.066
|
0.097
|
0.756
|
0.98
|
0.862
|
1.114
|
PA
|
-0.005
|
0.008
|
0.436
|
0.509
|
0.995
|
0.979
|
1.011
|
TG
|
0.227
|
0.267
|
0.723
|
0.395
|
1.255
|
0.743
|
2.119
|
HbA1c
|
0.179
|
0.115
|
2.401
|
0.121
|
1.196
|
0.954
|
1.499
|
ALB
|
-0.071
|
0.057
|
1.591
|
0.207
|
0.931
|
0.833
|
1.04
|
*P<0.05