High baseline SARS-CoV-2 RNAemia at the time of ICU admission is a prevalent finding in critically ill Covid-19 patients with comorbid diabetes and is strongly indicative of high mortality, according to a new study from France reported in iScience.¹

Researchers retrospectively analysed EMRs of 122 critically ill COVID-19 patients who were hospitalized in ICU during the third coronavirus wave from 4th March to 22nd June, 2021. They intended to study the association between the plasma viral load, comorbid conditions and mortality. The plasma viral load was quantified using droplet-based digital polymerase chain reaction (ddPCR). Other variables measured included neutrophil and lymphocyte counts, D-dimer, CRP, plasma creatinine and PaO2 on FiO2 ratio. Anti-SARS-CoV-2 Spike protein antibodies were also measured within 24 hours of admission to the ICU.

Ninety critically ill patients (74%) had detectable plasma SARS-CoV-2 viral RNA, ranging from 70 to 213,152 copies/ml. Forty-six (38%) of them had high (>1000 copies/ml) or very high (>10,000 copies/ml) plasma viral load. Out of these 46 patients, 26 (57%) had diabetes. Plasma SARS-CoV-2 RNA levels were independently associated with mortality at day 60 on multivariable analysis, “with an odds ratio of 2.45 or 3.53, depending on the model, per 10-fold increase above 316 copies/mL”. In addition to diabetes, high d-dimers, lower lower anti-spike antibody levels and shorter interval from onset of symptoms to ICU admission were associated with high plasma viral load.

After the onset of mild to moderate symptoms, some patients may become critically ill with respiratory worsening in the second week of illness. This has been attributed to the heightened inflammatory response. This is the time when these patients are in great peril. Therapies in such cases are principally directed at mitigating the inflammation and not viral replication.

But this study has shown that plasma SARS-CoV-2 RNA levels were markedly raised in critically ill Covid-19 patients at the time of ICU admission. Diabetic patients, in particular, had significantly higher SARS-CoV-2 RNAemia. The high viral load was “strongly and independently” associated with day-60 mortality. These findings suggest a prognostic role for plasma SARS-CoV-2 RNA levels, which can help the treating clinician identify candidates for early initiation of antiviral and anti-inflammatory treatments in patients with severe Covid-19.

Reference

1. Monchi M, et al. Association of high SARS-CoV-2 RNAemia with diabetes and mortality in COVID-19 critically ill patient. iScience. 2022 Mar 14;104075. doi: 10.1016/j.isci.2022.104075.