Associations of Clinical Characteristics and Intestinal Flora Imbalance in Stable Chronic Obstructive Pulmonary Disease (COPD) Patients and the Construction of an Early Warning Model

Figures & data

Figure 1 Patient flow diagram.

Table 1 Comparison of General Data Between the Two Groups

Characteristics	Control Group (n=154)	Experimental Group (n=41)	Statistics	P value
Age (years)^a	77(71,82)	76(73,84)	−0.513	0.608
Gender^c			0.505	0.477
Male	124(80.5)	35(85.4)
Female	30(19.5)	6(14.6)
BMI (kg/m^2)^a	24.80(23.38,26.60)	22.30(21.10,23.85)	−5.312	<0.001*
Smoking status^c			3.205	0.201
No smoker	88(57.1)	17(41.5)
Former smoker	47(30.5)	17(41.5)
Current smoker	19(12.3)	7(17.1)
Drinking status^c			1.782	0.455
No drinker	100(64.9)	29(70.7)
Former drinker	30(19.5)	9(22.0)
Current drinker	24(15.6)	3(7.3)
Hospital admission for COPD in the 1 previous years^c			2.787	0.095
0 or 1	111(72.1)	24(58.5)
≥2	43(27.9)	17(41.5)
Course of disease (years)^a	17(13,24)	17(13,23)	−0.543	0.587
FEV1/FVC (%)^a	55.34(46.43,60.55)	54.50(44.66,58.38)	−1.034	0.301
FEV1%pred (%)^a	48.90(41.05,62.18)	45.50(36.90,52.50)	−2.209	0.027*
GOLD classification^c			12.5	0.005*
GOLD I	16(10.4)	0(0.0)
GOLD II	54(35.1)	9(22.0)
GOLD III	74(48.1)	24(58.5)
GOLD IV	10(6.5)	8(19.5)
TG (mmol/L)^a	1.09(0.76,1.52)	0.97(0.66,1.32)	−1.149	0.251
TC (mmol/L)^a	4.04(3.56,4.78)	3.94(3.44,4.82)	−0.556	0.578
ALB (g/L)^a	36(32,38)	31(28,35)	−4.732	<0.001*
PaO2(mmHg)^a	96(94,98)	94.0(92.5,96.5)	−2.437	0.015*
WBC (*10^9/L)^a	6.60(4.88,8.63)	6.30(4.65,9.05)	−0.016	0.988
Lymphocyte count (*10^9/L)^a	1.30(0.85,1.71)	1.20(0.85,1.69)	−0.313	0.754
Eosinophil count (*10^9/L)^a	0.04(0.00,0.10)	0.01(0.00,0.11)	−0.935	0.35
Scr (umol/L)^a	70.9(56.9,83.10)	71.20(59.00,95.20)	−0.638	0.523
Fasting blood glucose (mmol/L)^a	5.27(4.39,6.18)	5.24(4.46,6.57)	−0.441	0.659
BNP (pg/mL)^a	45(35,63)	45(34,71)	−0.497	0.619
PASP (mmHg)^a	34(28,37)	34(33,38)	−1.194	0.233
Hb (g/L)^b	129.37±19.53	126.44±23.34	0.818	0.414
CAT score^a	9(7,14)	14(9,19)	−3.701	<0.001*
mMRC score^a	1(0,2)	2(1,3)	−4.227	<0.001*
CCI score^a	1(0.75,2)	3(2,4)	−8.181	<0.001*
GSRs score^a	1(0,1)	2(1,4)	−6.818	<0.001*
Inhaled corticosteroids (COPD controller)^c			1.423	0.233
Yes	22(14.3)	9(22.0)
No	132(85.7)	32(78.0)
Inhaled drugs as required (the leakage rate is less than 20%)^c			0.807	0.369
Yes	15(9.7)	6(14.6)
No	139(90.3)	35(85.4)

Notes: ^aM (P25, P75); ^b; ^cExample (%); *Compared with control group, P<0.05. GOLD classification (according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD)) classification into 4 groups: GOLD I: FEV₁%pred≥80%; GOLD II: 50%≤FEV₁%pred<80%; GOLD III: 30%≤FEV₁%pred<50%; GOLD IV: FEV₁%pred<30%.

Table 2 The Best Cut-Off Value of Predictor Variables and Youden Index

Covariates (Potential Predictors)	Best Cutoff Value	Youden Index	Sensitivity	Specificity
BMI	23.25	0.474	0.766	0.707
FEV1%pred	49.75	0.224	0.468	0.756
ALB	32.50	0.405	0.747	0.659
PaO2	96.50	0.237	0.481	0.244
CCI score	1.500	0.649	0.902	0.747
mMRC score	1.500	0.327	0.659	0.669
CAT score	8.500	0.290	0.829	0.461
GSRs score	1.500	0.451	0.659	0.792
GOLD classification	2.500	0.235	0.780	0.455

Table 3 Comparison of Categorical Predictors Between the Two Groups

Covariates (Potential Predictors)	Control Group (n=154)	Experimental Group (n=41)
BMI
≤23.25kg/m^2	36(23.4%)	29(70.7%)
>23.25kg/m^2	118(76.6%)	12(29.3%)
FEV1%pred
≤49.75%	82(53.2%)	31(75.6%)
>49.75%	72(46.8%)	10(24.4%)
ALB
≤32.5g/L	39(25.3%)	27(65.9%)
>32.5g/L	115(74.7%)	14(34.1%)
PaO2
≤97mmHg	95(61.7%)	32(78.0%)
>97mmHg	59(38.3%)	9(22.0%)
CCI score
≤2	142(92.2%)	12(29.3%)
>2	12(7.8%)	29(70.7%)
mMRC score
≤2	139(90.3%)	29(70.7%)
>2	15(9.7%)	12(29.3%)
CAT score
≤9	85(55.2%)	11(26.8%)
>9	69(44.8%)	30(73.2%)
GSRs score
≤2	145(94.2%)	22(53.7%)
>2	9(5.8%)	19(46.3%)
GOLD classification
GOLD I–II	70(45.5%)	8(19.5%)
GOLD III–IV	84(54.5%)	33(80.5%)

Table 4 Univariate and Multivariate Logistic Regression Analysis of Intestinal Flora Imbalance in Patients with Stable COPD

Predictors	Univariate Analysis				Multivariate Analysis
	β value	OR	P value	95%CI	β value	OR	P value	95%CI
BMI	-2.070	0.126	<0.001*	0.058–0.272	-2.406	0.090	<0.001*	0.026–0.317
FEV1%pred	-1.001	0.367	0.012*	0.168–0.807	2.010	7.460	0.161	0.450–123.767
ALB	-1.738	0.176	<0.001*	0.084–0.369	-1.280	0.278	0.040*	0.082–0.945
PaO2	-0.792	0.453	0.055	0.202–1.016	NS	–	–	–
CCI score	3.353	28.597	<0.001*	11.693–69.938	3.244	25.633	<0.001*	6.652–98.775
mMRC score	1.344	3.834	0.002*	1.626–9.044	1.454	4.281	0.094	0.782–23.427
CAT score	1.212	3.360	0.002*	1.571–7.186	0.093	1.097	0.894	0.280–4.302
GSRs score	2.633	13.914	<0.001*	5.595–34.605	2.840	17.113	<0.001*	4.012–72.997
GOLD classification	1.235	3.437	0.004*	1.491–7.923	3.237	25.469	0.034*	1.276–508.213
Constant					–	-4.332	0.013	0.009

Notes: *Compared with control group, P<0.05. COPD prediction model equation and performance using the aforementioned five independent variables. The logit model to determine PRE_1 was expressed as follows: Logit(p) = -4.332 + (-2.406 BMI) + (-1.280 ALB) + (3.244 CCI score) + (2.840 GSRs score) + (3.237 GOLD classification); ; e: natural logarithm (~2.718); x= -4.332 + (-2.406 BMI) + (-1.280 ALB) + (3.244 CCI score) + (2.840 GSRs score) + (3.237 GOLD classification).

Abbreviation: NS, No statistical significance.

Figure 2 ROC curve: 5 predictors predict the risk of intestinal flora imbalance in COPD.

Figure 3 ROC curve: ROC of PRE_1.

Table 5 Risk Score Sheet for Intestinal Flora Imbalance in Patients with Stable COPD

Risk Factors	Score Points
BMI
≤23.25kg/m^2	2
>23.25kg/m^2	0
ALB
≤32.5g/L	1
>32.5g/L	0
CCI score
≤2	0
>2	3
GSRs score
≤2	0
>2	3
GOLD classification
GOLD I–II	0
GOLD III–IV	3
	Total score 0–12

Figure 4 ROC curve: ROC of PRE_2.