We read with interest the study by Ampuero et al 1 on the vulnerability of primary biliary cholangitis (PBC) patients to SARS-CoV-2. Their study, conducted on patients from 13 referral hospitals, highlighted a heightened risk of infection and hospitalisation compared with the general population. However, we propose that their patient selection may inadvertently over-represent severe cases, thus introducing selection bias.

Using the CDC WONDER, a database with deidentified death records that included >99% of decedents in the USA, data associated with cirrhosis among adults aged 25 years and above were collected during 1 January 2012–31 December 2021. We estimated the age-standardised mortality rate (per 100 000 persons) using the direct method, referring to the 2000 US Census (standard population). To determine the impact of the pandemic on cirrhosis-related mortality (defined in online supplemental table S1), we conducted a Prophet model to predict mortality rates in 1 March 2020–31 December 2021 based on the 1 January 2012–28 February 2020 trend. Analysis for hepatitis C virus (HCV) decedents started in 2015 to coincide with the availability of new antivirals. The detailed methods were elaborated in online supplemental data file and online supplemental table S2.

[gutjnl-2023-330271supp001.pdf]

Among 878 601 cirrhosis-related deaths identified from1 January 2012 to 31 December 2021 (online supplemental table S3), there was a significantly increasing trend in cirrhosis-related …