The bottom line: Among critically ill individuals, the overall case fatality rate (CFR) is likely around 50% (between 49.0 and 61.5%) based on small case series; however, the CFR is likely highly dependent on age. Baseline clinical comorbidities (renal, diabetes > respiratory) are likely important as well but have not been systematically assessed.
Strength of evidence: Case fatality rates estimated from small, heterogeneous case series among critically ill individuals in China and the U.S.
Discussion: We could find no studies reporting age-stratified CFR in a cohort of exclusively mechanically ventilated participants; however, some meaningful information can be extrapolated from case series among critically ill individuals. In the first U.S. case series (from Evergreen Hospital in Kirkland, WA), Arentz et al. reported on n=21 PCR-confirmed cases admitted the the ICU from 2/20 to 3/5. Participants were 70 years old on average, 52% male. Chronic kidney disease and congestive heart failure were the most common comorbidities. The reported case fatality rate (CFR) was 52% as of 3/17. Importantly, at the end of the study period, eight participants were still intubated, so data on these eight individuals was censored, and the CFR may consequently be an underestimate.
In a case series from several Seattle-area hospitals published in NEJM, Bhatraju et al. reported on n=24 PCR-confirmed cases (all the individuals who presented to one of the study hospitals and were admitted to an ICU from 2/24 to 3/9). Participants were 64 years old on average, 63% men. Chronic kidney disease and diabetes were the most common comorbidites. The reported CFR was 50% (12). In individuals ≥65 years old, the CFR was 62% (vs. 37% in individuals < 65 years old). As with Arentz et al., at the end of the study period, several participants were still intubated (n=3), so the reported CFR may be an underestimate. Looking at individual-level data on the subset of participants who required mechanical ventilation (n=18), death also occurred in 50% (9) during the study period.
In a widely cited Lancet study, Yang et al. studied n=52 patients admitted to Wuhan Jin Yin-tan hospital who were intubated or required ≥60% FiO2. Participants were 59.7 years old on average, 67% men. Cardiovascular comorbidities and diabetes were common. The primary outcome was mortality at 28 days, which occurred in 61.5% of participants. CFR by age was: ≥80 years was 100% (3/3); 70–79: 87.5% (7/8); 60–69: 64.7% (11/17); 50–59: 69.2% (9/13); 40–49: 50% (3/6); 30–39: 0% (0/6). Among the subgroup of participants who required “invasive” ventilation (n=22), the CFR was 86.4% (19/22), but age-stratified CFR could not be calculated based on data available.
In Chinese CDC data (n=44,672 PCR-confirmed cases), among n=2,087 “critical” cases (defined as respiratory failure, septic shock, and/or multiorgan-system failure, the case-fatality rate was 49.0%.
Authors: Pandora “Luke” Wander, MD, MS, FACP
URLs:
https://jamanetwork.com/journals/jama/fullarticle/2763485
https://www.nejm.org/doi/full/10.1056/NEJMoa2004500
https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(20)30079-5/fulltext
https://www.ncbi.nlm.nih.gov/pubmed/32064853
Date last reviewed: 3/31/20
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