Association of Renal Impairment with Interleukin-6 Levels on Clinical Outcomes among COVID-19 Patients in a Tertiary Government COVID-19 Referral Hospital

Abstract

Objective. The objective of the study is to determine the association of renal impairment (AKI or CKD) with IL-6
levels on mortality, intubation, and length of hospitalization among COVID-19 positive patients.

Methods. This is a retrospective cohort study involving chart review of COVID-19 patients with IL-6 levels and
admitted from May 2020 to April 2021. The KDIGO criteria was used for determining renal impairment. The
subsequent data processing and analysis was carried out using the statistical software, Stata 13.

Results. A total of 1,120 charts were included with patients classified as having AKI (33%), CKD (14%), and no
renal impairment (58%). Overall mortality and need for intubation were 27% and 30%, respectively, with average
length of stay at 12 days. The IL-6 values were divided into low (0 to less than 51 pg/mL), intermediate (51 to
251 pg/mL), and high (greater than 251 pg/mL) tertiles, which showed acceptable sensitivity and specificity for
mortality and need for intubation.

Conclusion. The presence of renal impairment (CKD or AKI) with increasing IL-6 levels had an effect of increasing risk of adverse outcomes; however, within tertile groups, the presence of renal impairment did not significantly change the risk of adverse outcomes. The tertile groups have acceptable sensitivity and specificity for clinical use.