Utility of Rapid Influenza Molecular Testing in an Outpatient Hemodialysis Unit: A Prospective Cohort Study

Abstract

Background: Early initiation of antiviral therapy for individuals at risk for severe influenza infection is important for improving patient outcomes. Current guidelines recommend empiric antiviral therapy for patients with end-stage kidney disease presenting with suspected influenza infection. Rapid molecular influenza assays may reduce diagnostic uncertainty and improve patient outcomes by providing faster diagnostics compared to traditional batched polymerase chain reaction (PCR) testing. Objective: To determine the utility of implementing a rapid influenza PCR assay compared to the standard of care in a hemodialysis unit. Design: This is a prospective cohort study. Setting: A hospital-based dialysis unit in a tertiary care hospital. Patients: Adult patients with end-stage kidney disease on intermittent hemodialysis. Measurements: Patient characteristics, influenza PCR swab results, antibiotic prescriptions, antiviral prescriptions, emergency room visits and hospitalizations. Methods: From November 1, 2017 to March 31, 2018, we assigned samples collected from a single center, hemodialysis unit to be processed using a rapid influenza PCR (cobas® Influenza A/B & respiratory syncytial virus assay) or the standard of care (in-house developed multiplex PCR). Samples were assigned to the rapid PCR if the patient received dialysis treatment in the morning dialysis shift, while the remainder were processed as per standard of care. Study outcomes included the time from collection to result of nasopharyngeal swab, prescription of influenza antiviral therapy, time to receiving prescription, and the need for emergency department visit or hospitalization within 2 weeks of presentation. Results: During the study period, 44 patients were assessed (14 with the rapid PCR and 30 with the standard of care assay). Compared to conventional testing, the time to result was shorter using rapid PCR compared to conventional testing (2.3 vs 22.6 hours, P < .0001). Individuals who were tested using the rapid PCR had a tendency to shorter time to receiving antiviral prescriptions (0.7 days vs 2.1 days, P = .11), and fewer emergency department visits (7.1% vs 30%, P = .13) but no difference in hospitalizations (14.3% vs 30%, P = .46) within 2 weeks of testing. Limitations: This is a single center non-randomized study with a relatively small sample size. Patients who were tested using the standard of care assay experienced a delay in the prescription of antiviral therapy which deviates from recommended clinical practice. Conclusions: Rapid influenza molecular testing in the hemodialysis unit was associated with a shorter time to a reportable result and with a tendency to reduced time to prescription of antiviral therapy. Rapid molecular testing should be compared with standard of care (empiric therapy) in terms of economic costs, adverse events, and influenza-related outcomes.