The Effects of Obesity on the Comparative Effectiveness of Linezolid and Vancomycin in Suspected Methicillin-Resistant Staphylococcus aureus Pneumonia
|Caffrey AR1*, Noh E2, Morrill HJ2 and LaPlante KL3|
|1Infectious Diseases Research Program,Veterans Affairs Medical Center,Providence, Rhode Island, USA|
|2Department of Pharmacy Practice, College of Pharmacy,University of Rhode Island,Kingston, Rhode Island, USA|
|3Division of Infectious Diseases,Warren Alpert Medical School of Brown University,Providence, Rhode Island, USA|
|*Corresponding Author :||Caffrey AR
College of Pharmacy
University of Rhode Island
7 Greenhouse Road, Kingston
Rhode Island, USA
E-mail: [email protected]
|Received January 20, 2014; Accepted February 02, 2014; Published February 04, 2015|
|Citation: Caffrey AR, Noh E, Morrill HJ, LaPlante KL (2015) The Effects of Obesity on the Comparative Effectiveness of Linezolid and Vancomycin in Suspected Methicillin-Resistant Staphylococcus aureus Pneumonia. Adv Pharmacoepidemiol Drug Saf 4:176. doi:10.4172/2167-1052.1000176|
|Copyright: © 2015 Caffrey AR, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.|
Background: Methicillin-Resistant Staphylococcus aureus (MRSA) has become a leading cause of pneumonia in the United States and there is limited data on treatment outcomes in obese patients.We evaluated the effectiveness of linezolid compared to vancomycin for the treatment of MRSA pneumonia in a national cohort of obese Veterans.
Methods: This retrospective cohort study included obese patients (body mass index ≥ 30) admitted to Veterans Affairs hospitals with MRSA-positive respiratory cultures and clinical signs of infection between 2002 and 2012. Patients initiating treatment with either vancomycin or linezolid, but not both, were selected for inclusion. Propensity matching and adjustment of Cox proportional hazards regression models quantified the effect of linezolid compared with vancomycin on time to hospital discharge, intensive care unit discharge, 30-day mortality, inpatient mortality, therapy discontinuation, therapy change, 30-day readmission, and 30-day MRSA reinfection. We performed sensitivity analyses by vancomycin Minimum Inhibitory Concentrations (MICs) and true trough levels.
Results: We identified 101 linezolid and 2,565 vancomycin patients. Balance in baseline characteristics
between the treatment groups was achieved within propensity score quintiles and between propensity matched pairs (76 pairs). No significant differences were observed for the outcomes assessed. Among patients with vancomycin MICs of ≤ 1 μg/mL, the linezolid group had a significantly lower mortality rate, increased length of hospital stay, and longer therapy duration. There were no differences between the linezolid and vancomycin MICs of ≥ 1.5 μg/mL groups. Clinical outcomes among those with vancomycin trough concentrations of 15-20 mg/L were similar to patients treated with linezolid.
Conclusions: In our real-world comparative effectiveness study among obese patients with suspected MRSA pneumonia, linezolid was associated with a significantly lower mortality rate as compared to the vancomycin-treated patients with lower vancomycin MICs. Further studies are needed to determine whether this beneficial effect is observed in other study populations.