1593. Comparison of Outcomes with Linezolid- and Vancomycin-treated MRSA Pneumonia
Session: Poster Abstract Session: Community Acquired Pneumonia
Saturday, October 10, 2015
Room: Poster Hall
Background: In May 2013 our hospital’s clinical pathway/order form was reformatted to position linezolid (LIN) as the preferred agent for the treatment of MRSA pneumonia. The goal of this retrospective cohort study was to compare outcomes and costs of LIN treated patients with those treated with vancomycin (VAN). 

Methods: This study was conducted via retrospective chart and database review of eligible patients admitted to MUSC between 05/01/2011 and 08/31/2014, and with an ICD-9 code for MRSA and pneumonia. Eligible patients were at least 18 years of age, had vancomycin or linezolid initiated at least 2 days after admission and continued for at least 3 consecutive days. Hospital length of stay (LOS) was the primary outcome. Treatment duration, mechanical ventilation duration, all-cause mortality rate, nephrotoxicity, 30-day readmission and hospital costs were also analyzed across patients in the two treatment groups. Nominal variables were analyzed with Pearson’s chi-square test and continuous variables were analyzed with Student’s t-test or Wilcoxon rank-sum test, as appropriate. All tests were two-sided and all data were evaluated with SAS 9.3.  

Results: 227 patients were included in the study. The two treatment groups closely resembled each other with respect to gender, age, ethnicity, and Charleston Comorbidity Index. The main study results are displayed in the table. The only statistically significant difference was in all-cause mortality, favoring LIN-treatment.  

Conclusion: With the exception of mortality, the clinical outcomes of LIN- and VAN-treated patients were not statistically different. While suggestive of clinical superiority, these results must be interpreted with caution because of unaccounted for and potentially confounding variables.

Table: Main Outcomes

Characteristic  (median or number; range or %)

Linezolid (N = 150)

Vancomycin (N = 77)

P value

Hospital LOS

10 (2-121)

12 (3-147)

0.318

ICU LOS

4 (1-28)

4 (1-26)

0.199

Mechanical ventilation

10 (2-100)

7 (1-73)

0.335

Thrombocytopenia

8 (5.3%)

3 (3.9%)

0.754

Nephrotoxicity

5 (3.3%)

6 (8.9%)

0.098

30-day readmission

31 (20.7%)

14 (18.2%)

0.657

Mortality

15 (10.0%)

15 (19.5%)

0.046

Patient charge ($)

25,900 (4,240-495,400)

32,100 (5,790-437,700)

0.311

Manshan Celica Tong, PharmD, MPH1, John Bosso, PharmD, FIDSA2 and Christopher Wisniewski, PharmD1, (1)Pharmacy, Medical University of South Carolina, Charleston, SC, (2)Clinical Pharmacy & Outcome Sciences, South Carolina College of Pharmacy and Medical University of S. Carolina College of Medicine, Charleston, SC

Disclosures:

M. C. Tong, None

J. Bosso, Cempra: Scientific Advisor , Consulting fee
Cubist: Scientific Advisor , Consulting fee
Forest: Scientific Advisor , Consulting fee
Melinta: Scientific Advisor , Consulting fee
Pfizer: Scientific Advisor , Consulting fee
Medicines Co.: Scientific Advisor , Consulting fee

C. Wisniewski, None

Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 7th with the exception of research findings presented at the IDWeek press conferences.