Nomogram Model for Predicting the Risk of Multidrug-Resistant Bacteria Infection in Diabetic Foot Patients

Figures & data

Table 1 Constituent Ratios of the Isolated MDRB (%)

Pathogenic Bacteria	Number of Strains	Ratio (%)
Gram-positive bacteria	66	57.39
Staphylococcus aureus	30	26.09
Enterococcus faecalis	12	10.43
Staphylococcus epidermidis	9	7.83
Bird enterococcus	5	4.35
Staphylococcus haemolyticus	3	2.61
Others	7	6.09
Gram-negative bacteria	49	42.61
Proteus	17	14.78
Klebsiella pneumoniae	10	8.70
Escherichia coli	9	7.83
Morgan Morgan	3	2.61
Serratia marcescens	2	1.74
Citrobacter freundii	2	1.74
Providencia rettgeri	2	1.74
Others	4	3.48
Total	115	100

Abbreviation: MDRB, multidrug-resistant bacteria.

Table 2 Description of Baseline Data of Subjects

Demographic Characteristics	Total	Non-MDRB Group (n=98)	MDRB Group (n=101)
Age (years)	62.29 ± 9.16	60.11 ± 9.51	64.40 ± 8.32
BMI (kg/m^2)	24.90 ± 4.16	24.58 ± 4.02	25.22 ± 4.29
Fasting blood glucose (mmol/L)	13.19 ± 7.46	12.46 ± 7.69	13.89 ± 7.21
HbA1c (%)	9.74 ± 2.62	9.57 ± 2.62	9.90 ± 2.63
Basic illness
1 type	33 (16.58%)	16 (16.33%)	17 (16.83%)
2 types	57 (28.64%)	24 (24.49%)	33 (32.67%)
3 types and above	109 (54.77%)	58 (59.18%)	51 (50.50%)
With hypertension
No	96 (48.24%)	42 (42.86%)	54 (53.47%)
Yes	103 (51.76%)	56 (57.14%)	47 (46.53%)
With kidney disease
No	127 (63.82%)	64 (65.31%)	63 (62.38%)
Yes	72 (36.18%)	34 (34.69%)	38 (37.62%)
With blood system disease
No	159 (79.90%)	84 (85.71%)	75 (74.26%)
Yes	40 (20.10%)	14 (14.29%)	26 (25.74%)
With cardiovascular disease
No	174 (87.44%)	84 (85.71%)	90 (89.11%)
Yes	25 (12.56%)	14 (14.29%)	11 (10.89%)
With cerebral infarction
No	144 (72.36%)	65 (66.33%)	79 (78.22%)
Yes	55 (27.64%)	33 (33.67%)	22 (21.78%)
With hyperlipidemia
No	176 (88.44%)	83 (84.69%)	93 (92.08%)
Yes	23 (11.56%)	15 (15.31%)	8 (7.92%)
With osteoporosis
No	167 (83.92%)	92 (93.88%)	75 (74.26%)
Yes	32 (16.08%)	6 (6.12%)	26 (25.74%)
Sex
Male	117 (58.79%)	54 (55.10%)	63 (62.38%)
Female	82 (41.21%)	44 (44.90%)	38 (37.62%)
Education
Primary school or below	105 (52.76%)	47 (47.96%)	58 (57.43%)
Middle School	37 (18.59%)	20 (20.41%)	17 (16.83%)
University or above	57 (28.64%)	31 (31.63%)	26 (25.74%)
Course of disease
<10 years	111 (55.78%)	66 (67.35%)	45 (44.55%)
≥10 years	88 (44.22%)	32 (32.65%)	56 (55.45%)
Previous use of antibacterial drugs
No	77 (38.69%)	48 (48.98%)	29 (28.71%)
Yes	122 (61.31%)	50 (51.02%)	72 (71.29%)
Types of antibacterial drugs
<2	32 (16.08%)	23 (23.47%)	9 (8.91%)
≥2	167 (83.92%)	75 (76.53%)	92 (91.09%)

Abbreviations: MDRB, multidrug-resistant bacteria; BMI, body mass index; HbA1c, hemoglobin A1c.

Table 3 Single-Factor Logistic Analysis of Risk Factors for Infection in Patients with DF

Demographic Characteristics	Statistics	OR (95% CI)
Basic illness
1 type	33 (16.58%)	Ref
2 types	57 (28.64%)	1.29 (0.55, 3.06) 0.5576
3 types and above	109 (54.77%)	0.83 (0.38, 1.80) 0.6342
With hypertension
No	96 (48.24%)	Ref
Yes	103 (51.76%)	0.65 (0.37, 1.14) 0.1351
With kidney disease
No	127 (63.82%)	Ref
Yes	72 (36.18%)	1.14 (0.64, 2.03) 0.6672
With blood system disease
No	159 (79.90%)	Ref
Yes	40 (20.10%)	2.08 (1.01, 4.28) 0.0463
With cardiovascular disease
No	174 (87.44%)	Ref
Yes	25 (12.56%)	0.73 (0.32, 1.71) 0.4713
With cerebral infarction
No	144 (72.36%)	Ref
Yes	55 (27.64%)	0.55 (0.29, 1.03) 0.0623
With hyperlipidemia
No	176 (88.44%)	Ref
Yes	23 (11.56%)	0.48 (0.19, 1.18) 0.1089
With osteoporosis
No	167 (83.92%)	Ref
Yes	32 (16.08%)	5.32 (2.08, 13.59) 0.0005
Age (years)	62.29 ± 9.16	1.06 (1.02, 1.09) 0.0013
Sex
Male	117 (58.79%)	Ref
Female	82 (41.21%)	0.74 (0.42, 1.30) 0.2978
Education
Primary school or below	105 (52.76%)	Ref
Middle School	37 (18.59%)	0.69 (0.32, 1.46) 0.3314
University or above	57 (28.64%)	0.68 (0.36, 1.30) 0.2426
BMI	24.90 ± 4.16	1.04 (0.97, 1.11) 0.2771
Fasting blood glucose (mmol/L)	13.19 ± 7.46	1.03 (0.99, 1.07) 0.1803
HbA1c (%)	9.74 ± 2.62	1.05 (0.94, 1.17) 0.3742
Course of disease
<10 years	111 (55.78%)	Ref
≥10 years	88 (44.22%)	2.57 (1.44, 4.57) 0.0013
Previous use of antibacterial drugs
No	77 (38.69%)	Ref
Yes	122 (61.31%)	2.38 (1.33, 4.28) 0.0036
Types of antibacterial drugs
<2	32 (16.08%)	Ref
≥2	167 (83.92%)	3.13 (1.37, 7.18) 0.0069

Abbreviations: DF, diabetic foot; OR, odds ratio; CI, confidence interval; Ref, reference; BMI, body mass index; HbA1c, hemoglobin A1c.

Table 4 Multivariate Logistic Analysis of Risk Factors for Infection in Patients with DF

Demographic Characteristics	Statistics	OR (95CI)	P-value
With blood system disease			0.441
No	159 (79.90%)	Ref
Yes	40 (20.10%)	1.38 (0.61, 3.09)
Osteoporosis			0.003
No	167 (83.92%)	Ref
Yes	32 (16.08%)	4.54 (1.68, 12.24)
Age (years)	62.29 ± 9.16	1.05 (1.01, 1.09)	0.006
Course of disease			0.006
<10 years	111 (55.78%)	Ref
≥10 years	88 (44.22%)	2.48 (1.31, 4.69)
Previous use of antibacterial drugs			0.01
No	77 (38.69%)	Ref
Yes	122 (61.31%)	2.38 (1.23, 4.60)
Types of antibacterial drugs			0.013
<2	32 (16.08%)	Ref
≥2	167 (83.92%)	3.29 (1.29, 8.39)

Abbreviations: DF, diabetic foot; OR, odds ratio; CI, confidence interval; Ref, reference.

Figure 1 The nomogram model for predicting the risk of MDRB infection in patients with DF. **P<0.01.

Abbreviations: MDR, multidrug resistant; MDRB, multidrug-resistant bacteria; DF, diabetic foot.

Figure 2 Application example of a nomogram for predicting the risk of MDRB infection in patients with DF. **P<0.01.

Abbreviations: MDR, multidrug resistant; MDRB, multidrug-resistant bacteria; DF, diabetic foot.

Figure 3 DCA curve analysis of nomogram model.

Notes: The X-axis measures the predicted probability threshold of the MDRB infection in a patient by the nomogram model, and Y-axis measures Standardized net benefit. Nomogram showed the standardized highest net benefit and clinical usefulness in the DCA curve.

Abbreviations: DCA, decision curve analysis; MDRB, multidrug-resistant bacteria.

Figure 4 ROC curve analysis of different indicators.

Notes: The Y-axis indicates the sensitivity of the nomogram while the X-axis indicates the specificity of the nomogram. The AUC of the nomogram in predicting the probability of the MDRB infection in a patient was higher than any single indicator.

Abbreviations: ROC, receiver operating characteristic; AUC, area under curve; MDRB, multidrug-resistant bacteria.

Figure 5 ROC curve analysis of the nomogram model after internal verification.

Note: Y-axis indicates the sensitivity of the nomogram while the X-axis indicates the specificity of the nomogram.

Abbreviations: ROC, receiver operating characteristic; AUC, area under curve.

Figure 6 Calibration curve analysis of nomogram model after internal verification.

Notes: The Y-axis indicates the actual probability of the patient’s MDRB infection and the X-axis indicates the predicted probability of the patient’s MDRB infection. The 45-degree black dotted line represents the ideal prediction; the solid black line surrounding the 45-degree black dotted line represents the bias-corrected prediction; the black dotted line surrounding the 45-degree black dotted line represents the apparent prediction.

Abbreviation: MDRB, multidrug-resistant bacteria.