Data on how the utilization of the MRSA PCR nasal swab can affect LOS are limited; however, one study did report a 2.8-day reduction in LOS after implementation of a pharmacist-driven MRSA PCR nasal swab protocol.11 Our study demonstrated that LOS was significantly longer in the MRSA PCR group than in the no MRSA PCR group. This result was likely affected by the aforementioned sicker MRSA PCR population. Our multivariate analysis further confirmed that ICU admissions were associated with a longer LOS, and, given that the MRSA PCR group had a significantly higher ICU population, this likely confounded these results. If our 2 groups had had more evenly distributed characteristics, it is possible that we could have found a shorter LOS in the MRSA PCR group, similar to what is reported in the literature. In the subgroup analysis, LOS was 2 days shorter in the appropriate utilization group compared to the inappropriate utilization group. This further affirms that the results of the MRSA PCR must be used appropriately in order for patient outcomes, like LOS, to benefit.
The effects of the MRSA PCR nasal swab on 30-day readmission rates and incidence of AKI are not well-documented in the literature. One study did report 30-day readmission rates as an outcome, but did not cite any difference after the implementation of a protocol that utilized MRSA PCR nasal swab testing.12 The outcome of AKI is slightly better represented in the literature, but the results are conflicting. Some studies report no difference after the implementation of a MRSA PCR-based protocol,11 and others report a significant decrease in AKI with the use of the MRSA PCR.9 Our study detected no difference in 30-day readmission rates related to the previous admission or in AKI between the MRSA PCR and no MRSA PCR populations. In the subgroup analysis, 30-day readmission rates were significantly higher in the MRSA PCR group with appropriate utilization than in the group with inappropriate utilization; however, our study was not powered to detect a difference in this secondary outcome.
This study had some limitations that may have affected our results. First, this study was a retrospective chart review. Additionally, the baseline characteristics were not well balanced across the different groups. There were sicker patients in the MRSA PCR group, which may have led to an underestimate of the reduction in DOT and LOS in these patients. Finally, we did not include enough patient records to reach power in the MRSA PCR group due to a higher than expected number of patients meeting exclusion criteria. Had we attained sufficient power, there may have been more profound reductions in DOT and LOS.
Conclusion
MRSA infections are a common cause for hospitalization, and there is a growing need for antimicrobial stewardship efforts to limit unnecessary antibiotic usage in order to prevent resistance. As illustrated in our study, appropriate utilization of the MRSA PCR can reduce DOT up to 1.5 days. However, our results suggest that there is room for provider and pharmacist education to increase the use of MRSA PCR nasal swab testing in patients with LRTI receiving anti-MRSA therapy. Further emphasis on the appropriate utilization of the MRSA PCR within our health care system is essential.
Corresponding author: Casey Dempsey, PharmD, BCIDP, 80 Seymour St., Hartford, CT 06106; casey.dempsey@hhchealth.org.
Financial disclosures: None.