Association Between Thyroid Function and Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Figures & data

Table 1 Demographic and Clinical Characteristics of the Moderate-to-Severe Group Compared with the Very Severe Group

Characteristics	Moderate-to-Severe Group (n=97)	Very Severe Group (n=37)	P value
Demographic
Age years-old, Mean (SD)	71.10(10.40)	67.60(8.60)	0.076
Male, Number (%)	68(70.1)	31(83.8)	0.127
Normal BMI kg/m^2, Median (IQR)^a	20.86 (3.2)	19.75 (2.99)	0.376
Low BMI kg/m^2, Median (IQR)^b	17.10 (2.22)	16.27 (1.85)	0.108
High BMI kg/m^2, Median (IQR)^c	26.91 (3.12)	27.05 (0)	0.710
Clinical
Former smoker, Number (%)	25 (25.8)	14 (48.3)	0.203
Current smoker, Number (%)	25 (25.8)	15 (40.5)	0.138
Frequencies of AECOPD within one year≥2, Frequencies (%)	63 (64.9)	28 (75.7)	0.302
Course of disease-month, Median (IQR)	96(84)	120(60)	0.656
Lung function tests
FVC-L, Median (IQR)	1.83(0.72)	1.47(0.41)	<0.001
FEV1-L, Median (IQR)	0.98(0.43)	0.58(0.20)	<0.001
FEV1%pred, Median (IQR)	47.65(11.99)	23.63(4.56)	<0.001
Blood gas analysis
pH, Median (IQR)	7.42(0.04)	7.41(0.05)	0.603
PaO2-mmHg, Median (IQR)	74.70(17.10)	72.60(20.35)	0.435
PaCO2-mmHg, Median (IQR)	43.30(7.30)	47.80(8.30)	0.001
Biochemical indexes^d
Albumin-g/L, Mean (SD)	38.74(4.14)	38.58(3.89)	0.836
Thyroid hormone levels
FT3-pmol/L, Median (IQR)	4.11(1.03)	3.91(1.64)	0.077
FT4-pmol/L, Median (IQR)	15.42(5.86)	16.60(3.80)	0.502
TSH-mIU/L, Median (IQR)	1.05(1.16)	0.54(0.64)	0.001

Notes: ^aNormal BMI (18.5–24.9 kg/m²); ^bLow BMI (<18.5 kg/m²); ^cHigh BMI (≥24.9kg/m²); ^dOthers of biochemical indexes see supplemental Table 1.

Abbreviations: SD, standard deviation; BMI, body mass index; IQR, interquartile range (25th–75th percentile); AECOPD, acute exacerbation of chronic obstructive pulmonary disease; FVC, forced vital capacity; FEV₁, forced expiratory volume in 1 second; FEV₁%pred, FEV₁ as a percentage of the predicted value; FT₃, free triiodothyronine; FT₄, free tetraiodothyronine; TSH, thyroid-stimulating hormone; pH, pondus hydrogenii; PaCO₂, partial pressure of carbon dioxide; PaO₂, partial pressure of oxygen.

Table 2 Correlations Between FEV₁%pred, PaCO₂, PaO₂, Duration of Hospitalization, and Thyroid Hormone Levels

	FEV1%pred		PaCO2		PaO2		Duration of Hospitalization
	r	P	r	P	r	P	r	P
FT3	0.192	0.026	0.050	0.565	0.092	0.289	−0.137	0.115
FT4	−0.102	0.240	−0.031	0.720	0.137	0.114	0.052	0.550
TSH	0.329	<0.001	−0.108	0.214	0.004	0.959	−0.256	0.003

Abbreviations: PaCO_2, partial pressure of carbon dioxide; PaO₂, partial pressure of oxygen; FT₃, free triiodothyronine; FT₄, free tetraiodothyronine; TSH, thyroid-stimulating hormone; FEV₁%pred, forced expiratory volume in 1 second as a percentage of the predicted value.

Table 3 Clinical Data of Patients with AECOPD with Normal and Abnormal Thyroid Hormone Levels

Characteristics	Normal Thyroid Hormone Group (n=98)	Abnormal Thyroid Hormone Group (n=36)	P value
Demographic
Age years-old, Mean (SD)	68.88(10.07)	70.86(10.13)	0.619
Male, Number (%)	76(77.6)	23(63.9)	0.124
Normal BMI kg/m^2, Median (IQR)^a	20.96 (3.24)	20.54 (2.55)	0.692
Low BMI kg/m^2, Median (IQR)^b	16.97 (1.69)	16.33 (2.79)	0.412
High BMI kg/m^2, Median (IQR)^c	26.91 (3.06)	27.05 (4.91)	0.947
Clinical
Former smoker, Number (%)	31 (31.6)	8 (22.2)	0.391
Current smoker, Number (%)	27 (27.6)	13 (36.1)	0.396
Lung function tests
FVC-L, Median (IQR)	1.82(0.62)	1.38(0.46)	<0.001
FEV1-L, Median (IQR)	0.91(0.48)	0.70(0.47)	<0.001
FEV1%pred, Mean (SD)	42.72(15.01)	35.39(14.24)	0.030
Blood gas analysis
pH, Median (IQR)	7.41(0.05)	7.42(0.05)	0.670
PaO2-mmHg, Median (IQR)	74.15(20.30)	74.05(19.61)	0.690
PaCO2-mmHg, Median (IQR)	44.50(9.26)	44.15(11.45)	0.458
Biochemical indexes^d
Albumin-g/L, Mean (SD)	39.15(4.00)	37.47(4.01)	0.033

Notes: ^aNormal BMI (18.5–24.9 kg/m²); ^bLow BMI (<18.5 kg/m²); ^cHigh BMI (≥24.9kg/m²); ^dOthers of biochemical indexes see supplemental Table 2.

Abbreviations: AECOPD, acute exacerbation of chronic obstructive pulmonary disease; SD, standard deviation; BMI, body mass index; IQR, interquartile range (25th–75th percentile); FVC, forced vital capacity; FEV₁, forced expiratory volume in 1 second; FEV₁%pred, FEV₁ as a percentage of the predicted value; pH, pondus hydrogenii; PaCO₂, partial pressure of carbon dioxide; PaO₂, partial pressure of oxygen.

Table 4 Risk Factors for AECOPD Complicated with Abnormal Thyroid Function

Variables	OR	95% CI	P value
Smoking history	0.754	0.295~1.929	0.556
FVC	0.114	0.015~0.887	0.038
FEV1	1.930	0.042~87.975	0.736
FEV1%pred	0.990	0.943~1.040	0.697
Albumin	0.929	0.831~1.038	0.194

Abbreviations: AECOPD, acute exacerbation of chronic obstructive pulmonary disease; OR, odds ratio; CI, confidence interval; FVC, forced vital capacity; FEV₁, forced expiratory volume in 1 second; FEV₁%pred, FEV₁ as a percentage of the predicted value.