Prevalence, predictors, and outcomes of methicillin-resistant Staphylococcus aureus infections in patients undergoing major surgical procedures in the United States: a population-based study

Abstract

Background: National estimates of methicillin-resistant Staphylococcus aureus (MRSA) infection rates in hospitalized surgical patients and outcomes are lacking. We sought to estimate the prevalence, identify the predictors, and describe the outcomes of MRSA infections in hospitalized patients undergoing major surgical procedures (MSPs) in the United States.

Methods: We performed a retrospective analysis of the Nationwide Inpatient Sample, the largest all-payer hospital discharge database in the United States, for the years 2009 to 2010.

Results: Of the 22,932,948 hospitalizations that had an MSP, MRSA infection occurred in 235,636 (1.03%) patients. Factors associated with "significantly" lower risk of MRSA occurrence include women (odds ratio [OR] .68), elective procedure (OR .38), teaching institutes (OR .94), and large hospital size (OR .87). Blacks (OR 1.19), native Americans (OR 1.27), increased comorbid burden (OR 1.38), and uninsured patients were associated with higher risk of MRSA occurrence. Outcomes in MSPs "with" MRSA versus "without" MRSA include mean length of stay (14 vs 5 days) and in-hospital mortality (IHM) rate (3.7% vs 1.2%). Occurrence of an MRSA was associated with significantly longer length of stay and higher odds of IHM (OR 1.39, 95% confidence interval 1.30 to 1.48).

Conclusions: Although the occurrence of MRSA infections complicating MSPs was low, it is associated with worse outcomes. Certain predictors of MRSA infection are identified.

Keywords: Hospital-acquired infections—epidemiology; MRSA; Outcomes research; Surgical procedures.