More targeted use of oseltamivir and in-hospital isolation facilities after implementation of a multifaceted strategy including a rapid molecular diagnostic panel for respiratory viruses in immunocompromised adult patients

Background: Immunocompromised adults are more vulnerable to a complicated course of viral respiratory tract infections (RTI). Objectives: Provide evidence on the effect of implementation of rapid molecular diagnostics for viruses on use of in-hospital isolation facilities, oseltamivir and antibiotic usage, and other clinical outcomes in immunocompromised patients. Study design: A before-after study during two consecutive respiratory viral seasons, including immunocompromised adult patients presenting at a tertiary care emergency department with clinical suspicion of RTI. During the first season (2016/2017), respiratory viruses were detected using inhouse real-time PCR. The second season (2017/2018), we implemented a diagnostic flowchart including a rapid molecular test for 15 respiratory viruses (FilmArray (R)). We assessed the effect of this implementation on need for isolation, antivirals and empirical antibiotics. Results: We included 192 immunocompromised adult patients during the first and 378 during the second season. Respiratory viral testing was performed in 135 patients (70%) during the first and 284 (75%) during the second season (p = 0.218) of which 213 (75%) using the rapid test. After implementation, use of in-hospital isolation facilities was reduced (adjusted odds ratio 0.35, 95% CI 0.19-0.64). Furthermore, adequate use of oseltamivir improved, with fewer prescriptions in influenza negative patients (0.15, 95% CI 0.08-0.28) and more in influenza positive patients (11.13, 95% CI 1.75-70.86). No effect was observed on empirical antibiotic use, hospital admissions, length of hospital stay or safety outcomes. Conclusions: Implementation of rapid molecular testing for respiratory viruses in adult immunocompromised patients results in more adequate use of oseltamivir and in-hospital isolation facilities without compromising safety.