Risk factors for failure for Intraabdominal Infections: the importance of site of infection

Background:

Approximately 20% of patients with complicated intra-abdominal infections (IAI) will fail therapy. Despite defining risk factors for failure in patients who received surgical intervention, limited data exists for patients outside this criterion. The purpose of this study is to identify risk factors for clinical failure in patients with IAI, regardless of surgical intervention.

Methods:

This retrospective case-control identified patients with ICD-9 codes related to IAI. Key inclusion criteria included adult patients who received at least 48 hours of intravenous antibiotics. Key exclusion criteria included concomitant different bacterial infection and IAI or trauma in the last 90 days. Collected data included demographics, severity of illness scores, and treatment information. The primary outcome was clinical failure, defined as in-hospital mortality, repeat procedure, empiric antibiotic escalation, or fever after 96 hours of antibiotic therapy. Univariate analysis was performed using Chi-Square, Fisher’s Exact test, Student’s t-test, or Mann-Whitney U test. Multivariate analysis was performed using multivariable logistic regression.

Results:

1405 patients were screened: 211 patients were included. The median (IQR) age and length of stay were 54 (37-63) years and 8 (6-11) days, respectively. 59 patients (28%) had clinical failure. Selected variables associated with clinical failure in the evaluable population (n = 204) are shown in Table 1.

Table 1. Variables Associated with Clinical Failure.	N (% total population) or median (IQR)	Unadjusted OR (95% CI)	Adjusted OR (95% CI)
Weight (kg)	83.915 (68.040-99.6778)	1.008 (0.995-1.021)	N/A
Serum Creatinine (mg/dL)	0.910 (0.7050-1.2050)	1.355 (1.048-1.751)	1.444 (1.023-2.039)
Biliary	74 (36.3)	0.353 (0.173-0.723)	0.328 (0.153-0.702)
Peritonitis	76 (37.3)	2.329 (1.250-4.339)	N/A
Non-White	122 (59.8)	1.734 (0.910-3.307)	N/A
Vancomycin Receipt	27 (13.2)	1.902 (0.823-4.392)	N/A

N/A- removed from the model

Conclusion:

In a mixed surgical intervention population of IAI patients, peritonitis and serum creatinine were independent predictors of clinical failure. Regardless of surgical intervention status, risk factors for failure in IAI patients were similar.