Objective:

To investigate whether IL-6 is a prognostic factor in SARS-CoV-2 related encephalopathy in development of PASC.

Background:

It is currently unclear whether elevated IL-6 can be a prognostic factor in development of PASC.

Design/Methods:

A retrospective chart review was performed on hospitalized SARS-CoV-2 infection encephalopathy patients during March-May of 2020 at an urban tertiary care center. Patients were divided into two subgroups according to critically elevated (CE-IL6) vs non-critically elevated (NCE-IL6) initial serum IL-6 levels (as defined as >86.95 pg/mL as per previous literature). Charts were analyzed for patients who had follow-up between 4 weeks and 1 year from initial visit to analyze subsequent development of new or persisting respiratory, cardiac, renal, or neurological symptoms to determine incidence of PASC. 

Results:

Of 57 encephalopathy SARS-CoV-2 infection patients reviewed, 29 and 28 patients were found to be in the CE-IL6 and NCE-IL6 groups, respectively (average serum IL-6 level of 543.73 pg/mL vs 47.85 pg/mL, p = 0.0039). Among the CE-IL6 group, 68.97% patients had follow-up at least 4 weeks post admission vs 64.29% in NCE-IL6 group (p > 0.05), with an average total follow up time of 529.89 days post initial admission in CE-IL6 and 520.31 days for NCE-IL6 (p > 0.05). In the follow-up CE-IL6 group, 90% reported any one of the PASC symptoms whereas in the follow-up NCE-IL6 group, 22.22% reported any PASC symptoms (RR = 4.05, 95% CI [1.69-9.73], p = 0.0018). 12 patients received Tocilizumab (IL-6 inhibitor) in the CE-IL6 group and only 58.33% of them developed PASC.

Conclusions:

Encephalopathic patients who had critically elevated IL-6 serum levels on initial hospital admission for SARS-CoV-2 infection may be at increased risk of developing of PASC which could be attenuated by IL-6 inhibitor. Work in progress to confirm these findings by expanding sample size, increasing follow up time and stratifying for confounding factors.