A case-control study to evaluate the economic outcome of early PO linezolid in patients with methicillin-resistant Staphylococcus aureus infections

Abstract number: 1134_02_70

Davis S., Shieh M., Levine D., McKinnon P.

Oral therapy with linezolid (LZD) has the potential to decrease hospital costs and shorten length of stay of patients with Gram-positive infections who would otherwise continue to receive IV therapy.

Objective:

To evaluate the impact of early PO conversion to LZD in patients receiving traditional IV therapy for methicillin-resistant S. aureus (MRSA) infections.

Methods:

Patients with documented MRSA infection between 2001 and 2004 were evaluated in a matched case-control study. Cases included patients who were converted to PO LZD from IV LZD or IV vancomycin (VANC), and controls were patients who received only IV VANC. Patients were paired in a 1:2 ratio of cases to controls and matched based on infection type, age and comorbidities. Demographics, antimicrobial agents, concomitant infections, and clinical status were assessed daily from the onset of infection through the end of treatment or hospitalization. Antibiotic cost, length of stay (LOS), and clinical success rates were compared between the groups.

Table 1 includes comparisons of cost, duration of therapy and LOS. Predictably, patients receiving LZD in the hospital had higher drug costs; however, a decreased LOS contributed to a $7000 lower cost of hospitalization.

Results:

78 patients were assessed. Demographic characteristics were similar between groups. Average age (mean ± SD) was 46 ± 14; APACHE II (median, range) was 6 [0–22], Charlson comorbidity score 2 [0–8], and 60% were male. 55% of patients were treated for skin/soft tissue infection, 19% pneumonia, 13% bone/joint infections, 11% bacteraemia, and 2% other infections. Clinical and microbiologic outcomes were similar between groups, with 100% clinical success at the end of therapy.

Conclusions:

Oral therapy with linezolid shortens LOS decreasing hospital cost of patients with MRSA infections.