Association Between RT-PCR Cycle Threshold and Outcomes of Individuals Hospitalized for COVID-19

Area of Science:

• Infectious Diseases
• Virology
• Medical Diagnostics

Background:

• Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection presents with variable clinical severity.
• Reverse transcription polymerase chain reaction (RT-PCR) of nasopharyngeal swabs is the gold standard for diagnosing SARS-CoV-2 infection.
• RT-PCR provides semiquantitative viral load assessment via cycle threshold (CT) values.

Purpose of the Study:

• To determine if admission CT values can predict mortality in hospitalized coronavirus disease 2019 (COVID-19) patients.
• To assess the association between admission CT values and the need for oxygen support.

Main Methods:

• A retrospective study of 636 adult COVID-19 patients hospitalized between August 2020 and April 2021.
• Patients were classified into high (CT ≥ 25) and low (CT < 25) viral load groups based on initial CT values.
• Primary outcome was the association between CT values and overall mortality.

Main Results:

• Patients with lower CT values (< 25) exhibited significantly higher mortality (OR 1.78, P = 0.002).
• A greater proportion of patients in the low CT group required oxygen support (50% vs. 31.9%, P < 0.001).
• Multivariate analysis confirmed an inverse association: a 1-unit decrease in CT value correlated with a 6% increase in mortality.

Conclusions:

• Lower admission CT values are significantly associated with increased mortality in COVID-19 patients.
• CT values serve as a valuable tool for predicting clinical outcomes in hospitalized COVID-19 patients.