Linezolid May Be Better Choice for Diabetics With MRSA Pneumonia

September 23, 2011

By Fran Lowry

(Reuters Health) - In diabetics with nosocomial pneumonia (NP) caused by methicillin-resistant Staphylococcus aureus (MRSA), linezolid trumped vancomycin for clinical and microbiologic success, researchers said in Chicago this week.

But in patients without diabetes, results with both drugs were comparable, Dr. Ozlem Equils, from Pfizer Inc., Collegeville, PA, said at the 51st Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC).

Dr. Equils and his group presented the results of a post-hoc sub-group analysis of data from the ZEPHyR study, a phase IV randomized, double-blind, multicenter trial of linezolid versus vancomycin in patients with MRSA-NP.

The researchers assessed outcomes 7 to 30 days after the end of treatment with either linezolid 600 mg IV twice daily or vancomycin 15 mg/kg IV twice daily, adjusted for creatinine clearance.

Patients with and without diabetes had similar demographics, comorbidities, microbiology, and APACHE II scores.

The clinical success rate at the end of treatment among the 87 diabetics treated with linezolid was 58%, versus 39% for the 96 diabetics treated with vancomycin (p=0.03). Microbiological success rates were 59% with linezolid vs 41% with vancomycin (p = 0.03).

Rates of 28-day mortality, drug-related adverse events, serious adverse events, and study drug discontinuation rates were similar between the treatment groups.

Among the non-diabetics, the clinical success rate was 53% in the 137 patients treated with linezolid and 49% in the 128 who received vancomycin (p =0.60). Microbiological success rates were 56% with linezolid and 50% with vancomycin (p = 0.37).

As in the diabetic group, mortality, adverse events, and drug discontinuation rates were similar with the two drugs.

"While definitive conclusions cannot be drawn from retrospective analyses, these findings provide important information that may help guide physicians in making treatment decisions for patients with nosocomial pneumonia," Dr. Equils told Reuters Health.

He added that the findings align with data from previous studies showing that linezolid was at least as effective as vancomycin for the treatment of nosocomial pneumonia, including ventilator-associated pneumonia due to known or suspected MRSA across patient types.


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