Cost Study of Linezolid Versus Vancomycin Among Previously Hospitalized Patients

This is a retrospective, observational, non-interventional drug study using de-identified data from two administrative claims datasets. The study design and analysis will reflect the perspective of the commercially insured. The objectives of this study are twofold:

1. To compare the rates of re-hospitalization among patients treated with either linezolid orally or IV, or vancomycin IV for complicated skin and skin structure infections (cSSSI) or pneumonia hospitalization.
2. To compare the total direct medical costs of patients treated with linezolid orally or IV, or vancomycin IV for cSSSI or pneumonia hospitalization.

Study Overview

• Status: Completed
• Conditions: Complicated Skin and Structure Infection; Nosocomial Pneumonia
• Intervention / Treatment: Drug: Linezolid; Drug: Vancomycin

Detailed Description

A sampling method is not used in this study since it is a retrospective, non-interventional claims database analysis. Pre-specified inclusion/exclusion criteria and ICD-9, NDC, HCPC codes are applied to identify the study cohorts.

• Study Type: Observational
• Enrollment (Actual): 7260

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 64 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

The study population will consist of patients with a hospitalization for complicated skin and skin structure infections (cSSSI) or pneumonia. We will identify cases from January 1, 2007, to September 30, 2009, with additional 6 months pre-period and up to 6 months of post-index follow-up period.

Description

Inclusion Criteria:

Subjects must meet all of the following inclusion criteria to be eligible for enrollment into the study:

• Patients with a hospitalization for cSSSI or pneumonia for which the discharge date (i.e. index date) is between January 1, 2007 and September 30, 2009.
• Patient must have a claim for either vancomycin (IV) or linezolid (IV or oral) within 7 days following their cSSSI or pneumonia hospitalization discharge date (i.e. index date). We will exclude patients who initially receive both vancomycin and linezolid on the same day. We will apply an intention-to-treat approach and use the first drug as the index drug, even if the "comparator drug" (e.g. vancomycin for linezolid and vice-versa) is used subsequently on a future date. If there are both oral and IV formulations of the same index drug on the same index date, the patient will be kept and categorized as an IV user. As with all duplicate claims, for two claims that have both oral and IV index drug as well as the same IV and oral costs on the same index date, the claim with the oral drug will be removed, and the patient will be called an IV user.
• 18-64 years of age at index date.
• Continuous eligibility for six months prior to the index hospitalization date. No minimum of post-index continuous enrolment is required to assure that early mortality patients are included (maximum of 180 days after the index vancomycin or linezolid claim).

Exclusion Criteria:

Subjects presenting with any of the following will not be included in the study:

• Patients who were enrolled in Medicare.
• Patients who were over age 65 or younger than 18.
• Patients with fewer than 3 days of oral therapy.
• Patients with index hospitalization of greater than 30 days.
• Patients with osteomyelitis, infective endocarditis, meningitis, joint infections, necrotizing fasciitis, gangrene, prosthetic joint infection, or prosthetic implant/ device infection during index hospitalization.

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Retrospective

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
complicated skin and skin structure infections (cSSSI); Identified through a pre-specified list of ICD-9 codes in study protocol.	Drug: Linezolid; IV and oral forms of linezolid are identified through a pre-specified list of National Drug Codes (NDCs).; Drug: Vancomycin; IV form of vancomycin is identified through a pre-specified list of National Drug Codes (NDCs).
Pneumonia; Identified through a pre-specified list of ICD-9 codes in study protocol.	Drug: Linezolid; IV and oral forms of linezolid are identified through a pre-specified list of National Drug Codes (NDCs).; Drug: Vancomycin; IV form of vancomycin is identified through a pre-specified list of National Drug Codes (NDCs).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Rehospitalization	42 days
Total reimbursed amount following hospital discharge	42 days

Collaborators and Investigators

• Sponsor: Pfizer
• Collaborators: University of Maryland; Lodise & Lodise, LLC

Study record dates

Study Major Dates

• Study Start: May 1, 2011
• Primary Completion (Actual): May 1, 2012
• Study Completion (Actual): May 1, 2012

Study Registration Dates

• First Submitted: May 27, 2011
• First Submitted That Met QC Criteria: May 27, 2011
• First Posted (Estimate): June 1, 2011

Study Record Updates

• Last Update Posted (Estimate): May 22, 2012
• Last Update Submitted That Met QC Criteria: May 21, 2012
• Last Verified: May 1, 2012

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Infections; Respiratory Tract Infections; Respiratory Tract Diseases; Pneumonia; Lung Diseases; Disease Attributes; Cross Infection; Iatrogenic Disease; Healthcare-Associated Pneumonia; Molecular Mechanisms of Pharmacological Action; Anti-Infective Agents; Enzyme Inhibitors; Anti-Bacterial Agents; Protein Synthesis Inhibitors; Vancomycin; Linezolid
• Other Study ID Numbers: A5951160

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No