Background: Duration of intravenous (IV) treatment, surgical/radiologic interventions for infection control, and hospital length of stay (LOS) are important cost considerations in complicated intra-abdominal infections (cIAIs).
Methods: Data were pooled from two multinational, double-blind studies conducted in hospitalized adults with cIAIs who were randomized (1:1) to receive tigecycline (100 mg IV initial dose then 50 mg IV every 12 h) or imipenem–cilastatin (500 mg IV every 6 h) for 5 to 14 days in order to assess tigecycline safety and efficacy. This report focuses on developing predictors of cure and health care resource utilization, including the need for repeat surgical/radiologic interventions, duration of IV antibiotic therapy, and hospital LOS. Multiple regression models were applied for each of the above outcomes, incorporating both baseline and on-treatment potential covariates. Logistic modeling was used for categorical outcomes (cure; repeat surgical/radiologic interventions) and least squares modeling for continuous outcomes (duration of IV antibiotic therapy; LOS). Stepwise selection was used to retain only those predictors found to be significant (p < 0.05) independent risk factors.
Results: The most common causative pathogen was Escherichia coli (63.0%), with 63.3% of the patients exhibiting polymicrobial infections. The most common cIAI diagnosis was complicated appendicitis (51.9%). Lack of clinical cure (+6.1 days; p < 0.0001), perforation of the intestine (+3.7 days; p < 0.0001), an Acute Physiology and Chronic Health Evaluation (APACHE) score >15 (+3.1 days; p = 0.039), abnormal plasma sodium concentration (+3.7 days; p = 0.026), and repeat surgical/radiologic intervention (+2.2 days; p = 0.0097) were identified as key risk factors for longer LOS. Inadequate source control was associated with reduced odds of cure, longer IV treatment duration (+1.5 days; p = 0.007), and longer LOS. The treatment groups did not differ in terms of LOS, IV treatment duration, or clinical cure.
Conclusion: Tigecycline was similar to imipenem–cilastatin in terms of both efficacy and health resource utilization. Risk factors identified in this study for both outcome measures are offered as support for guiding clinical practice.
