The Daniel K. Inouye College of Pharmacy Scripts: The Effects of Vancomycin Use and De-escalation in Patients Hospitalized with Pneumonia.

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) causes about 80,000 severe infections each year. Compared to Methicillin-susceptible Staphylococcus aureus (MSSA), MRSA is associated with higher mortality and increased hospital length of stay (LOS). Vancomycin hydrochloride, an antibiotic with activity against MRSA is often used as empiric therapy for pneumonia. However, current pneumonia treatment guidelines recommend against the routine use of MRSA coverage since MRSA prevalence rates are low. In this retrospective, observational study, 38.3% of the population received vancomycin while only 2.6% had evidence of a MRSA infection. Data was gathered manually from electronic medical records from four hospitals over a six-month period. To identify a well-balanced comparison and account for potential confounders, matching on the propensity scores was conducted. Prior to matching, those who received vancomycin had a significantly higher rate of mortality (14.3% vs 4.9%, P < .001) and higher LOS (9.6 days vs 7.2 days, P < .001). Those who were de-escalated from vancomycin had a significantly lower LOS (8.3 days vs 11.6 days, P = .001) with no difference in mortality. After performing a survival analysis on matching data, those who received vancomycin had a significantly higher LOS (9.2 days vs 7.5 days, P = .002) with no difference in mortality (P = .1737). Those who were de-escalated had a significantly lower LOS (8.3 days vs 11.3 days, P=.005) with no difference in mortality (P = .8624). This study demonstrates a low prevalence of MRSA with the potential overuse of vancomycin. This along with no difference in mortality and a lower LOS supports the recommendation to limit vancomycin use as clinically appropriate. If vancomycin is used, assessment for rapid de-escalation is needed.