Use of Oritavancin as Outpatient Treatment for ABSSTIs Generates Potential Cost Savings at Community Hospital

The results of a study published in the July 2018 issue of Hospital Pharmacy provide additional evidence in support of the use of oritavancin as a cost-saving outpatient treatment for acute bacterial skin and skin structure infections (ABSSTIs) in patients who would otherwise be admitted to the hospital for therapy.

ABSSTIs are the leading cause of infection-related hospital admissions in the United States, in part, because treatment for these infections often requires 5 to 14 days of intravenous (IV) antibiotics. In addition to the cost of the treatment, these admissions incur room, lab, and other hospital-associated costs. Furthermore, many patients who are admitted for ABSSTIs do not have existing comorbidities, systemic signs of infection, or evident symptoms of infection other than the site of the infection itself. As such, the development of an effective treatment that could be administered to these patients over less time, and in the outpatient setting, is desirable.

One such treatment that offers shorter dosing time and outpatient administration is oritavancin (Orbactiv; The Medicines Company).

Approved by the US Food and Drug Administration (FDA) in 2014, oritavancin is a lipoglycopeptide antibiotic indicated for the treatment of infections with gram-positive bacteria such as Staphylococcus aureus and methicillin-resistant S aureus (MRSA). It is administered as a one-time, 1200-mg IV dose, infused over 3 hours. In previous studies, oritavancin was found to be noninferior to the most common treatment for S aureus and MRSA, an (up to) 10-day, twice-a-day, 1 g or 15 mg/kg dose of IV vancomycin.

Because of its shorter dosing requirement, which could lead to increased cost-savings, and its comparable effectiveness to vancomycin, oritavancin was added to the formulary of a large community hospital in the Northeast Georgia Health System in June 2015. Following this addition, investigators set out to determine whether or not the drug was appropriately prescribed among clinicians at the hospital and if the drug did, indeed, offer cost-savings for the institution.

For the study, investigators conducted a retrospective chart review of the hospital’s electronic medical records and clinical documentation notes in the pharmacy surveillance software. All patients who received oritavancin through the health system between June 2015 and October 2016 were identified and of those patients, 67 were included in the analysis.

Appropriateness of prescribing was determined by whether or not the prescriber followed the FDA-approved indications for oritavancin as well as the hospital’s restricted antimicrobial use criteria. Oritavancin was considered an appropriate therapy for the following: ABSSTIs, including cellulitis, cutaneous abscess, and wound infections. The use of oritavancin for the treatment of osteomyelitis and bacteremia (non-FDA-approved indications) was considered inappropriate.

The results of the study indicated oritavancin was appropriately prescribed for the majority (76%) of patients (n = 51), of whom, 49.3% were prescribed the medication for cellulitis. The remaining 24% of patients (n = 16) were inappropriately prescribed oritavancin, with osteomyelitis being the most common indication (10.6%).

Infectious disease physicians (including hospital-employed infectious disease clinicians and private infectious disease clinicians) made up the majority of prescribers (54%), followed by emergency department physicians (25%), cardiologists (12%), and hospitalists (9%). Of note, a sub-analysis of the data revealed that the majority of patients who were inappropriately prescribed oritavancin (n = 13) received their prescription from 1 private infection disease physician.

Most patients (90%) received oritavancin in the hospital’s outpatient infusion center and in the emergency department; 10% of patients received oritavancin in the inpatient setting prior to discharge.

The financial impact was determined in conjunction with the readmission rate. Criteria for a readmission included any patient who returned to the health system within 14 days of treatment with oritavancin with complaints of the same infection, according to the study authors.

Eight patients (12%) “presented back to the ED with complaints of the same infection within 14 days of oritavancin therapy,” the authors wrote; however, none of the patients were readmitted to the hospital, and most were prescribed an alternate oral therapy (such as clindamycin, amoxicillin-clavulanate, and doxycycline) and were able to return home. Moreover, none of the 67 patients in the study were readmitted to the hospital within 14 days of therapy.

To determine financial impact, the investigators compared the cost of 1 dose of oritavancin with the cost of hospitalization for inpatient treatment—“calculated by multiplying the duration of hospitalization (in days) by the cost-per-day of a hospital bed,” according to the authors. An average length-of-stay of 6.62 days for skin and soft tissue infections was determined based on hospital data from the previous year.

Presuming the length-of-stay at 6.62 days and a cost per day of $1,999 (based on the national average), the investigators indicated that the average hospital stay would cost about $13,233 per patient. Conversely, the average cost of a 1200-mg dose of oritavancin (based on the average wholesale cost of three, 400 mg vials) would be $3480. Therefore, the estimated cost-savings per patient, if they were prescribed oritavancin in an outpatient-setting, would be $9753. “If applied to the current sample size, appropriate use of oritavancin to prevent admissions for ABSSTIs has the potential to save our hospital an estimated $653,451 annually,” the study authors wrote.

Limitations of the study include its small sample size at a single-center as well as “the use of a national average for hospitalization cost-per-day instead of an institution-specific cost,” according to the authors.

Based on these results, the investigators contend that appropriate use of oritavancin for the treatment of ABSSTIs as an outpatient alternative could offer significant cost savings by preventing hospital admissions.