493. Linezolid vs. Vancomycin: Re-hospitalization Rates among Patients with Pneumonia, Staphylococcal Infection, and Skin and Soft Tissue Infection
Session: Poster Session: Hospital-acquired and Transplant Infections
Friday, October 30, 2009: 12:00 AM
Room: Poster Hall A
Background: Clinical trials of anti-infective drugs provide evidence of differences in survival and cure rates; however, there are additional clinical and economic measures of comparative effectiveness that are of interest to payers, such as the rate of re-hospitalization. The objectives of this study were to compare infection-related re-hospitalization rates for vancomycin (VAN) versus linezolid (LZD) users who were treated for pneumonia, staphylococcal infection (SI), and/or skin and soft tissue infections (SSTI).
Methods: Patients were non-Medicare adults between the ages of 18-64 who were hospitalized for pneumonia, SI, or SSTI and prescribed either VAN or LZD (index drug) during the study period. Administrative claims databases from HealthCore Integrated Research Database (HIRD), i3 Innovus (i3) and IMS PharMetrics (PM) were used. The main outcome was re-hospitalization for an infection within the observation period, which was defined as the earlier of the last day of continuous eligibility or 180 days after index date. Adjusted odds of repeat hospitalization were calculated using logistic regression models, which controlled for patient demographics and co-morbidities.
Results: Unadjusted rates for infection-related re-hospitalizations for VAN and LZD were 39.9% versus 33.7% for pneumonia; 29.5% versus 17.9% for SI; and 29.1% versus 22.5% for SSTI, respectively (all p < 0.01). Adjusted logistic regression models confirmed that LZD was associated with a 23.3%, 44.2% and 27.3% relative risk reduction in re-hospitalization (all p < 0.01) among patients with pneumonia, SI and SSTI, respectively.
The number needed to treat (NNT) to avoid a re-hospitalization by using LZD versus VAN was 9 among the SI group, suggesting that for every additional 9 patients treated with LZD versus VAN there would be one fewer patient re-hospitalized. The NNT was 16 and 17, respectively, for patients with SSTI and pneumonia.
Conclusion: Compared to VAN, LZD was associated with lower rates of re-hospitalization among patients initially hospitalized with pneumonia, SI, or SSTI.
Catherine Cooke, PharmD, PosiHealth, Inc., Ellicott City, MD, Van Doren Hsu, PharmD, University of Maryland School of Pharmacy, Baltimore, MD, C. Daniel Mullins, PhD, University of Maryland, School of Pharmacy, Baltimore, MD, Eli Perencevich, MD, MS, FIDSA, FSHEA, Department of Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, Ahmed Shelbaya, MD, MPH, MSc, Pfizer Inc., New York, NY, Anna Wallace, MPH, HealthCore, Wilmington, DE and  C. Mullins,
Pfizer Role(s): Consultant, Grant Investigator, Research Relationship, Scientific Advisor (Review Panel or Advisory Committee), Speaker's Bureau, Received: Educational Grant, Grant Recipient, Research Grant, Research Support, Speaker Honorarium, Consulting Fee.
Sanofi-Aventis Role(s): Consultant, Grant Investigator, Investigator, Research Relationship, Scientific Advisor (Review Panel or Advisory Committee), Speaker's Bureau, Received: Educational Grant, Grant Recipient, Research Grant, Research Support, Speaker Honorarium, Consulting Fee.
Genentech Role(s): Consultant, Received: Consulting Fee.
Novartis Role(s): Grant Investigator, Investigator, Research Relationship, Scientific Advisor (Review Panel or Advisory Committee), Received: Educational Grant, Grant Recipient, Research Grant, Consulting Fee.
Lilly Role(s): Consultant, Received: Consulting Fee.
V. Hsu, None. 
C. E. Cooke,
Pfizer Role(s): Speaker's Bureau, Received: Speaker Honorarium.
Lilly Role(s): Grant Investigator, Received: Grant Recipient.
Novartis Role(s): Grant Investigator, Received: Grant Recipient.
A. M. Shelbaya,
Pfizer, Inc. Role(s): Employee, Shareholder (excluding diversified mutual funds), Received: Salary.
A. E. Wallace, None. 
E. N. Perencevich,
Pfizer, Inc. Role(s): Grant Investigator, Research Relationship, Received: Grant Recipient, Research Grant.
Merck Role(s): Grant Investigator, Research Relationship, Received: Grant Recipient, Research Grant.