Long-Term Risk for Readmission, Methicillin-Resistant Staphylococcus aureus (MRSA) Infection, and Death among MRSA-Colonized Veterans

Abstract

While numerous studies have assessed the outcomes of methicillin-resistant S. aureus (MRSA) colonization over the short term, little is known about longer-term outcomes after discharge. An assessment of long-term outcomes could provide information about the utility of various MRSA prevention approaches. A matched-cohort study was performed among Veterans Affairs (VA) patients screened for MRSA colonization between the years 2007 and 2009 and followed to evaluate outcomes until 2010. Cox proportional-hazard models were used to evaluate the association between MRSA colonization and long-term outcomes, such as infection-related readmission and crude mortality. A total of 404 veterans were included, 206 of whom were MRSA carriers and 198 of whom were noncarriers. There were no culture-proven MRSA infections on readmission among the noncarriers, but 13% of MRSA carriers were readmitted with culture-proven MRSA infections on readmission (P < 0.01). MRSA carriers were significantly more likely to be readmitted, to be readmitted more than once due to proven or probable MRSA infections, and to be readmitted within 90 days of discharge than noncarriers (P < 0.05). Infection-related readmission (adjusted hazard ratio [HR] ‫؍‬ 4.07; 95% confidence interval [CI], 2.16 to 7.67) and mortality (adjusted HR ‫؍‬ 2.71; 95% CI, 1.87 to 3.91) were significantly higher among MRSA carriers than among noncarriers after statistically adjusting for potential confounders. Among a cohort of VA patients, MRSA carriers are at high risk of infection-related readmission, MRSA infection, and mortality compared to noncarriers. Noncarriers are at very low risk of subsequent MRSA infection. Future studies should address whether interventions such as nasal or skin decolonization could result in improved outcomes for MRSA carriers.

Molecular characterization of methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization and infection isolates in a Veterans Affairs hospital

“…In addition to infections, MRSA can be found to asymptomatically colonize sites such as the nose and throat. The prevalence of MRSA nasal colonization in the general U.S. population is approximately 1 – 2% [ 3 ], but can exceed 13% among admitted Veterans Affairs (VA) hospital patients [ 2 ] and 10 to 15% of patients within U.S. acute-care hospitals and intensive care units [ 4 ].…”

Clinical effectiveness of treatment strategies for Staphylococcus aureus prosthetic joint infections

“…We also did not include a PJI-free control group to investigate the general trend in mortality rates among veterans, as this person-years (45%) and 8.1 per 100 person-years (23%) in greater than 1 year of follow-up. (191) Death rates observed in our study were lower compared to these studies. We also used propensity score matching and instrumental variable methodologies to account for the potential of bias in database studies.…”

Prevalence of Nasal Colonization and Strain Concordance in Patients with Community-AssociatedStaphylococcus aureusSkin and Soft-Tissue Infections

“…8,9,28 Among hospitalized patients with primarily invasive (eg, bloodstream) infections, strain relatedness between nasal and clinical isolates occurs in approximately 80% of cases. 12,25,29 For unknown reasons, this colonizing-infecting strain relatedness does not seem to bear out with SSTI.…”