Cefazolin Plus Ceftazidime versus Cefazolin Monotherapy in the Treatment of Culture-Negative Peritonitis: A Retrospective Cohort Study

Figures & data

Figure 1 Flow diagram for selection of the study cohort.

Figure 2 Flow diagram of the antibiotic prescription decision-making process in the management of PD-related peritonitis and routine of laboratory tests in our clinical practice.

Table 1 Comparison of Patient Characteristics and Clinical Data Based on Antibiotic Therapy

Clinical Variables	Combination (n=42)	Monotherapy (n=16)	p-value
Age: (years) mean ± SD	66.6 ± 11.73	63.6 ± 9.3	0.32
Sex: male n (%)	23 (54.8)	7 (43.6)	0.56
BMI (kg/m^2): mean ± SD	22.87 ± 0.80	22.85 ± 0.81	0.98
PD duration (months)	40.5 ± 4.67	30.8 ± 8.12	0.27
PD mode: n (%)			<0.001*
-CAPD	39 (92.9)	8 (50.0)
-APD	3 (7.1)	8 (50.0)
Causes of ESKD			0.68
-Diabetic nephropathy	25 (59.5)	10 (62.5)
-Hypertension	6 (14.3)	4 (25.0)
-Obstructive uropathy	2 (4.76)	0
-Unknown/other	9 (21.43)	2(12.5)
CCI: mean ± SD	6.26 ± 1.83	6.25 ± 1.65	0.98
ATB usage 30 days prior peritonitis: n (%)	1(2.38)	0	0.52
Clinical presentation
Fever: n (%)	12 (28.57)	4 (25.0)	0.78
Abdominal pain	33 (78.57)	12 (75.0)	0.77
Cloudy peritoneal fluid	9 (21.4)	5 (31.3)	0.43
Laboratory results
WBC in PDF at initial diagnosis: mean ± SD	4211± 10357	3833± 6931	0.89
Hemoglobin (g/dL)	9.84± 1.77	10.01± 1.88	0.72
WBC (cell/mm^3): mean ± SD	8960± 6733	7386± 3037	0.37
Albumin (g/dL): mean ± SD	2.63 ± 0.53	3.02± 0.64	<0.02*
Potassium (mEq/L): mean ± SD	3.62 ± 0.56	3.60± 0.45	0.88

Note: *p-value less than 0.05.

Abbreviations: APD, automated peritoneal dialysis; ATB, antibiotic; CAPD, continuous ambulatory peritoneal dialysis; CCI, Charlson comorbidity index; ESKD, end stage kidney disease; WBC, white blood cell; PMN, polymorphonuclear neutrophil; PDF, Peritoneal dialysis fluid.

Table 2 Empirical Antibiotic Regimens and Clinical Outcomes of Culture-Negative Peritonitis by Antibiotic Treatment in Subsequent Management

Clinical Outcomes	Combination (n=42)	Monotherapy (n=16)	p-value
Empirical antibiotics			0.46
Cefazolin plus Ceftazidime: n (%)	36 (83.33)	16 (100)
Vancomycin plus Ceftazidime: n (%)	1 (2.38)	0
Piperacillin/tazobactam: n (%)	1 (2.38)	0
Meropenem: n (%)	4(9.52)	0
Clinical outcomes
Primary response: n (%)	40(95.2)	15 (93.7)	0.82
Relapsing peritonitis: n (%)	2 (4.76)	0	0.37
Catheter removal: n (%)	2 (4.76)	1 (6.25)	0.82
Death: n (%)	1(2.38)	0	0.53

Figure 3 Kaplan–Meier curves of cumulative primary response in culture-negative peritonitis patients who received cefazolin plus ceftazidime (combination) and those who received cefazolin alone (monotherapy).

Table 3 The Results of Univariate and Multivariate Cox Regression Analysis Regarding Primary Response

Clinical Factors	Univariate			Multivariate
	HR	95% CI	p-value	HR	95% CI	p-value
Age	1.04	0.99–1.04	0.18	1.04	0.98–1.04	0.24
CCI	1.07	0.93–1.25	0.34	1.03	0.82–1.28	0.78
Fever	1.25	0.29–2.28	0.45
Cloudy fluid	0.77	0.40–1.47	0.43
Initial effluent WBC	0.99	0.99–1.00	0.67
WBC	0.99	0.99–1.0	0.34
Hemoglobin	1.15	0.95–1.39	0.15	1.10	0.92–1.33	0.28
Serum potassium	1.96	1.13–3.40	0.02*	1.83	1.06–3.20	0.03*
Albumin ≥ 3.5 (g/dL)	1.47	0.66–3.26	0.34
ATB monotherapy	0.58	0.31–1.07	0.08	0.57	0.31–1.06	0.07

Note: *p-value less than 0.05.

Abbreviations: ATB, antibiotic; CCI, Charlson comorbidity index; OR, odds ratio; WBC, white blood cell.