SARS-CoV-2 RNAemia as a reliable predictor of long-term mortality among older adults hospitalized in pulmonary intermediate care units: a prospective cohort study

Background: SARS-CoV-2 viremia is associated with disease severity and high risk for in-hospital mortality. However, the impact of SARS-CoV-2 viremia on long-term outcomes in hospitalized patients with COVID-19 is poorly understood.

Methods: We conducted a prospective cohort study and recruited a group of older adult patients with COVID-19 admitted to pulmonary intermediate care units of Peking University Third Hospital during December 2022 and January 2023. The plasma level of SARS-CoV-2 RNA was determined by a standardized RT-PCR technique, and SARS-CoV-2 RNAemia was defined as a plasma viral load ≥ 50 copies/ml. In-hospital and follow-up (180-day) outcome data were collected.

Results: A total of 101 patients with an average of 80.4 years were recruited, and 63.4% of them were severe or very severe cases. Twenty-eight patients (27.7%) had SARS-CoV-2 RNAemia, with a median viral RNA load of 422.1 [261.3, 1085.6] copies/ml. Patients with SARS-CoV-2 RNAemia were more likely to develop critical cases and had a higher incidence of sepsis. Accordingly, they had a higher 180-day mortality (57.1% vs. 19.7%, P < 0.001), as well as in-hospital mortality (50.0% vs. 13.7%, P < 0.001), independent of age, disease severity, sepsis, lymphocyte count and C-Reactive protein. In addition, the risk for 180-day mortality increased with the SARS-CoV-2 RNA load in plasma. Plasma cytokines, including IL-6, IL-8 and IL-10, were higher in patients with SARS-CoV-2 RNAemia.

Conclusions: Our study indicates that SARS-CoV-2 RNAemia serves as a useful biomarker for predicting mortality, especially long-term mortality, in older adult patients hospitalized in pulmonary intermediate care units.

Trial registration: Chinese Clinical Trial Registry website (No. ChiCTR2300067434).