Risk factors for pulmonary infection after thoracoscopic radical resection of lung cancer in elderly patients with diabetes mellitus

Table 1 Distribution of pathogens

Pathogenic bacteria	Number	Composition ratio (%)
Gram positive bacteria	19	35.85
Staphylococcus aureus	10	18.87
Streptococcus pneumoniae	2	3.77
Staphylococcus epidermidis	7	13.21
Gram negative bacteria	34	64.15
Acinetobacter baumannii	5	9.43
Pseudomonas aeruginosa	14	26.42
Klebsiella pneumoniae	8	15.09
Escherichia coli	4	7.55
Tenotrophomonas maltophilia	3	5.66

Table 2 Comparison of general data, mean ± SD/n (%)

Items		Infected group (n = 41)	Non-infected group (n = 171)	t/χ2 value	P value
Age (years old)	≥ 70	27 (65.85)	76 (44.44)	4.767	0.029
	60-69	14 (34.15)	95 (55.55)
Sex (cases)	Male	24 (58.54)	112 (65.50)	0.697	0.404
	Female	17 (41.46)	59 (34.50)
Body mass index (kg/m2)		25.42 ± 2.13	24.79 ± 2.09	1.547	0.123
Smoking history	With	23 (56.10)	101 (59.06)	0.120	0.729
	Without	18 (43.90)	70 (40.94)
Drinking history	With	22 (53.66)	79 (46.20)	0.738	0.390
	Without	19 (46.34)	92 (53.80)
Hypertension	With	27 (65.85)	94 (54.97)	1.599	0.206
	Without	14 (34.15)	77 (45.03)
Hyperlipidemia	With	14 (34.15)	82 (47.95)	2.544	0.111
	Without	27 (65.85)	89 (52.05)
Respiratory diseases	With	25 (60.98)	71 (41.52)	5.052	0.026
	Without	16 (39.02)	100 (58.48)
TNM stage	I stage	16 (39.02)	98 (57.31)	4.448	0.035
	II-III stage	25 (60.98)	73 (42.69)
Maximum diameter of tumor	≥ 4 cm	22 (53.66)	60 (35.09)	4.809	0.028
	< 4 cm	19 (46.34)	111 (64.91)
Neoadjuvant chemotherapy	≥ 2 times	27 (65.85)	64 (37.43)	10.908	< 0.001
	< 2 times	14 (34.15)	107 (62.57)
Pathological type	Squamous carcinoma	22 (53.66)	111 (64.91)	1.792	0.181
	Adenocarcinoma	19 (46.34)	60 (35.09)

TNM: Tumor node metastasis.

Table 3 Comparison of surgical treatment and laboratory indicators, mean ± SD/n (%)

Items		Infected group (n = 41)	Non-infected group (n = 171)	t/χ2 value	P value
Operation time (hour)	≥ 3	25 (60.98)	72 (42.11)	4.745	0.029
	< 3	16 (39.02)	99 (57.89)
Intraoperative bleeding (mL)	≥ 800	11 (26.83)	38 (22.22)	0.395	0.530
	< 800	30 (73.17)	133 (77.77)
Extent of excision	Multi leaf	28 (68.29)	75 (43.86)	7.903	0.005
	Single leaf	13 (31.71)	96 (56.14)
Thoracic drainage tube time (day)	≥ 3.5	26 (63.41)	61 (35.67)	10.519	< 0.001
	< 3.5	15 (36.59)	110 (64.33)
Forced expiratory volume in one second (%)	< 80	28 (68.28)	68 (39.77)	10.861	< 0.001
	≥ 80	13 (31.71)	103 (60.23)
White blood cell count (× 109/L)		8.42 ± 1.39	8.79 ± 1.15	-1.774	0.078
C-reactive protein (mg/L)		3.42 ± 1.51	3.73 ± 1.45	-1.220	0.224
Albumin (g/L)		39.74 ± 1.72	41.87 ± 1.62	-7.471	< 0.001
Fasting blood glucose (mmol/L)		7.02 ± 1.25	6.48 ± 1.21	2.55	0.011
Hemoglobin A1c (%)		8.12 ± 1.04	7.12 ± 1.01	5.661	< 0.001

Table 4 Risk factors and their assignment for pulmonary infection in patients

Factor	Variable	Assignment
Age	X1	60-69 years old, 0; ≥ 70 years old, 1
TNM stage	X2	I stage, 0; II-III stage, 1
Respiratory diseases	X3	No, 0; Yes, 1
Neoadjuvant chemotherapy	X4	< 2 times, 0; ≥ 2 times, 1
Maximum diameter of tumor	X5	< 4 cm, 0; ≥ 4 cm, 1
Operation time	X6	< 3 hours, 0; ≥ 3 hours, 1
Range of excision	X7	Single leaf, 0; multi leaf, 1
Thoracic drainage tube time	X8	< 3.5 days, 0; ≥ 3.5 days, 1
Forced expiratory volume in one second	X9	≤ 80%, 0; > 80%, 1
Albumin	X10	Actual measurement value
Fasting blood glucose	X11	Actual measurement value
Hemoglobin A1c	X12	Actual measurement value

TNM: Tumor node metastasis.

Table 5 Multivariate risk analysis for postoperative pulmonary infection in elderly diabetic lung cancer patients

Factor	P value	OR	95%CI
Age	0.063	2.735	0.948-7.89
TNM stage	0.084	2.486	0.886-6.973
Respiratory diseases	0.849	1.105	0.397-3.071
Neoadjuvant chemotherapy	0.036	2.987	1.072-8.318
Maximum diameter of tumor	0.013	3.959	1.341-11.69
Operation time	0.079	2.518	0.899-7.051
Range of excision	0.036	3.18	1.08-9.361
Thoracic drainage tube time	0.224	1.878	0.68-5.186
Forced expiratory volume in one second	0.029	3.305	1.129-9.673
Albumin	0.000	0.507	0.362-0.709
Fasting blood glucose	0.562	1.132	0.745-1.719
Hemoglobin A1c	0.003	2.39	1.346-4.241

OR: Odds ratio; CI: Confidence interval; TNM: Tumor node metastasis.

Table 6 Area under the curve for predicting postoperative pulmonary infection in elderly diabetic lung cancer patients

Factor	AUC	SE	95%CI
Neoadjuvant chemotherapy	0.642	0.048	0.548-0.736
Maximum diameter of tumor	0.593	0.05	0.495-0.691
Range of excision	0.622	0.048	0.528-0.716
Forced expiratory volume in one second	0.667	0.046	0.577-0.757
Albumin	0.795	0.039	0.718-0.871
Hemoglobin A1c	0.744	0.044	0.659-0.829

AUC: Area under the curve; CI: Confidence interval.