Abstract: Letter to the Editor
doi: 10.1111/joim.13163
Use of the IL-6R antagonist tocilizumab in hospitalized
COVID-19 patients
Dear Editor,
Severely ill COVID-19 patients have a high risk of
admission to the intensive care unit (ICU) and
requirement for mechanical ventilation (MV), with
in-hospital mortality reported as 18-79% globally
[1-4]. Amongst ICU patients in the United States
(US), centres have reported 50% mortality [5, 6].
Tocilizumab, an IL-6 receptor (IL-6R) antagonist, is
FDA approved for the management of CAR T-cellrelated cytokine release syndrome (CRS) and may
have utility in treatment of some COVID-19
patients. We describe the clinical characteristics
and initial outcomes of a cohort of patients treated
with tocilizumab at the Swedish Medical Center in
Seattle, Washington.
Methods
This retrospective cohort study included 42 adults
(≥18 years old) hospitalized for COVID-19 and
treated with tocilizumab at Swedish Medical Center
(Seattle, USA) between 16 March 2020 and 17 April
2020. To provide context, we identified a cohort of
41 matched patients not receiving tocilizumab.
Patients enrolled in prospective clinical trials of
tocilizumab were excluded from the study.
All data were abstracted from the electronic medical record and reviewed by a second investigator.
Baseline patient demographic and clinical characteristics including severity of COVID-19 illness
using the Chinese CDC definition were recorded
up to 10 days prior to anti-cytokine therapy [4].
Clinical variables and major changes in clinical
status such as admission to the ICU, initiation of
MV, initiation of extracorporeal membrane oxygenation (ECMO) or death are described for 42
patients treated with tocilizumab. Survival and
clinical outcomes were assessed for 42 tocilizumab-treated patients and 41 matched controls for
whom at least 7 days of follow-up data were
available or who had been discharged or died
before 7 days following administration of tocilizumab or the corresponding time for the matched
controls.
430
ª 2020 The Association for the Publication of the Journal of Internal Medicine
Continuous variables were expressed as median
values with interquartile (IQR) or absolute ranges
or means with standard deviations (SD). Categorical variables were described as a proportion of the
total subjects in percentages. Spaghetti plots were
constructed to show the course of various parameters with respect to time before and after administration of tocilizumab, and a smoothing curve
was fit to these data to show overall trends across
time. Probability of discharge was summarized
using cumulative incidence estimates, where death
without discharge was treated as a competing risk.
Analyses were performed with SAS version 9.4
software.
Informal comparisons were made to the matched
controls simply as a means of providing context for
the results observed amongst tocilizumab-treated
patients. Controls who did not receive tocilizumab
were matched 1:1 to tocilizumab-treated patients
on exact World Health Organization (WHO) score at
hospital admission and exact WHO score on the
hospitalization day on which the matched tocilizumab patient received therapy (regarded as day 0 to
correspond with day 0 of tocilizumab delivery). Day
0 and age were added to the matching algorithm
with bands around perfect matching as follows:
day 0 5 days and age 10 years. Matching was
performed in Stata v13.1 with calipmatch, using
greedy matching without replacement.
Results
Forty-two patients..
DOI record:
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