The cost-effectiveness of cefepime plus metronidazole versus imipenem/cilastatin in the treatment of complicated intra-abdominal infection

Cost-effectiveness analysis comparing ceftazidime/avibactam (CAZ-AVI) as empirical treatment comparing to ceftolozane/tazobactam and to meropenem for complicated intra-abdominal infection (cIAI)

Background

The rising incidence of resistance to currently available antibiotics among pathogens, particularly Gram-negative pathogens, in complicated intra-abdominal infections (cIAIs) has become a challenge for clinicians. Ceftazidime/avibactam (CAZ-AVI) is a fixed-dose antibiotic approved in Europe and the United States for treating (in combination with metronidazole) cIAI in adult hospitalised patients who have limited or no alternative treatment options. The approval was based on the results of RECLAIM, a Phase III, parallel-group, comparative study (RECLAIM 1 [NCT01499290] and RECLAIM 2 [NCT01500239]). The objective of our study was to assess the cost-effectiveness of CAZ-AVI plus metronidazole compared with 1) ceftolozane/tazobactam plus metronidazole and 2) meropenem, as an empiric treatment for the management of cIAI in Italy.

Methods

A sequential, patient-level simulation model, with a 5-year time horizon and 3% annual discount rate (applied to both costs and health benefits), was developed using Microsoft Excel® to demonstrate the clinical course of the disease. The impact of resistant pathogens was included as an additional factor.

Results

In the base-case analysis, the CAZ-AVI sequence (CAZ-AVI plus metronidazole followed by a colistin + tigecycline + high-dose meropenem combination after treatment failure), when compared to sequences for ceftolozane/tazobactam (ceftolozane/tazobactam plus metronidazole followed by colistin + tigecycline + high-dose meropenem after treatment failure) and meropenem (meropenem followed by colistin + tigecycline + high-dose meropenem after treatment failure), had better clinical outcomes with higher cure rates (93.04% vs. 91.52%; 92.98% vs. 90.24%, respectively), shorter hospital stays (∆ = − 0.38 and ∆ = − 1.24 days per patient, respectively), and higher quality-adjusted life years (QALYs) gained per patient (4.021 vs. 3.982; 4.019 vs. 3.960, respectively). The incremental cost effectiveness ratio in the CAZ-AVI sequence was €4099 and €15,574 per QALY gained versus each comparator sequence, respectively, well below the willingness-to-pay threshold of €30,000 per QALY accepted in Italy.

Conclusions

The model results demonstrated that CAZ-AVI plus metronidazole could be a cost-effective alternative when compared with other antibiotic treatment options, as it is expected to provide better clinical benefits in hospitalised patients with cIAI in Italy.

Economic evaluation of doripenem for the treatment of nosocomial pneumonia in the US: discrete event simulation

OBJECTIVE

Patients with nosocomial pneumonia, particularly associated with ventilator use, are at an increased risk of death and further morbidity. Doripenem is a new broad-spectrum carbapenem that is approved for complicated intra-abdominal infection and complicated urinary tract infection and is under the Food and Drug Administration (FDA)'s review for nosocomial pneumonia and ventilator-associated pneumonia in the United States (US). The economic implications of this new antibiotic, relative to imipenem for treatment of nosocomial pneumonia, were investigated.

RESEARCH DESIGN AND METHODS

An economic model of the clinical course of nosocomial pneumonia after initiation of treatment was developed using discrete event simulation. Pairs of identical patients are generated; one receives doripenem and the other receives imipenem. Their clinical course is simulated using clinical trial data on treatment response, seizure rates, mortality, length of hospital and intensive care unit stays, days on mechanical ventilation, and emerging Pseudomonas aeruginosa (PsA) resistance; published treatment and hospital costs; and PsA transmission risk. Analyses of 10,000 patients per treatment for 100 replications were performed. From the perspective of a comprehensive payer, costs - in 2007 US Dollars (USDs) - were estimated for a treatment episode (35-49 days) without discounting. Study limitation includes clinical trial-driven design of the model in which some aspects may not represent actual practice; some assumptions around efficacy data due to data unavailability; and lack of consideration of factors that impact disease transmission such as hospital environment, hospital size, and hospital infection control as these analyses were not intended for any specific healthcare institution.

RESULTS

Doripenem yielded an average of approximately $7000 in savings per patient compared to imipenem, with 95% driven by reduction in hospital length of stay. The model predicted 63% fewer seizures, 52% fewer emerging PsA resistance, and 15% shorter stays leading to 46% fewer transmissions associated with doripenem.

CONCLUSION

Using doripenem for treatment of nosocomial pneumonia is expected to yield significant savings compared to imipenem use in the US.

Cost analysis of five antimicrobial regimens for the treatment of intra-abdominal infection

BACKGROUND

Cost of treatment is an important consideration in antimicrobial agent selection for intra-abdominal infection. We analyzed the relation between the total cost of inpatient stay and the initial selection of antimicrobial agent.

METHODS

Actual costs of inpatient care were calculated for 1,234 patients treated at 22 hospitals with one of five antimicrobial regimens: Ampicillin/sulbactam (n = 428), ertapenem (n = 143), ceftriaxone (n = 101), levofloxacin (n = 245), or piperacillin/tazobactam (n = 317) for intra-abdominal infections. Length of stay (LOS), demographic data, diagnosis, disease severity index, intensive care unit (ICU) stay, and total and specific costs were obtained from a large hospital-based, service level, comparative database for five types of infection (appendicitis, cholecystitis, diverticulitis, pancreatitis, and postoperative infection).

RESULTS

The LOS was shorter for appendicitis (3.8 days) and cholecystitis (4.6 days) than for diverticulitis (11.4 days), pancreatitis (8.1 days), or postoperative infection (8.4 days). Length of stay and total cost were most closely related to severity index (p < 0.01) and ICU days (p < 0.01). When patient and hospital characteristics and correlations within hospitals were accounted for in the model, piperacillin/tazobactam was associated with significantly higher cost than ertapenem, ampicillin/sulbactam, and levofloxacin.

CONCLUSIONS

In assessing pharmacoeconomic outcomes in the treatment of intra-abdominal infection, cost of treatment, although lower with certain antimicrobial agents, is dependent on severity-of-illness indicators.

Intra-abdominal infections: considerations for the use of the carbapenems

Intra-abdominal infection remains a common and frequently severe medical condition, carrying with it significant morbidity and mortality. These infections are almost always polymicrobial in nature as they are caused by mixed aerobic/anaerobic intestinal flora. Despite substantial improvements in both the medical and surgical management of these infections over the last several decades, there remains an opportunity to further enhance the utilization of adjunctive antibiotic therapy. As a result of the epidemiology and the current resistance profile of the infecting pathogens, the carbapenems represent a class of antibiotics that are considered appropriate for the treatment of severe intra-abdominal infections. This review will discuss the classification and microbiology of these infections and emerging resistance in the pathogens of interest. The review also and focuses on the role of the carbapenems in the management of the constellation of diseases known as intra-abdominal infection.