Cycle threshold values are inversely associated with poorer outcomes in hospitalised patients with Covid-19: a prospective, observational cohort study conducted at a UK tertiary hospital.

Wright, Jenny; Achana, Felix; Diwakar, Lavanya; Semple, Malcolm G; Carroll, Will D; Baillie, Kenneth; Thompson, Christopher; Alcock, Alice; Kemp, Timothy S

In this single centre observational study, we demonstrated that lower cycle threshold (Ct) values (indicating higher viral loads) on admission to hospital, were associated with poorer outcomes in unvaccinated, hospitalised patients with Covid-19. We prospectively collected demographic and outcome data on all adult patients who tested positively for SARS-CoV-2 on admission to the University Hospitals North Midlands (UHNM) NHS Trust between 1(st) February and 1(st) July 2020. Nasopharyngeal swab samples were obtained, and a valid Ct value determined for all patients using the Public Health England (PHE) validated Viasure© reverse transcription PCR assay on admission to hospital. Multivariable logistic regression results based on data from 618 individuals demonstrated a statistically significant inverse relationship between the odds of death and Ct values (adjusted odds ratio (aOR) 0.95, 95% CI 0.92 to 0.98, p-value 0.001). The association remained highly statistically significant after adjusting for known clinical risk factors for the disease.