Response to letter entitled: Tixagevimab/cilgavimab pre-exposure prophylaxis and breakthrough infection risk in vaccinated solid organ transplant recipients: Concern for immortal time bias effect
Year: 2023
Type: letter
Abstract: In their Letter to the Editor, Riggs et al 1 Riggs J. Charya A. Eberlein M. Reed R. Saharia K. Tixagevimab/cilgavimab pre-exposure prophylaxis and breakthrough infection risk in vaccinated solid organ transplant recipients: concern for immortal time bias effect. Am J Transpl. 2022; https://doi.org/10.1016/j.ajt.2022.11.021 Abstract Full Text Full Text PDF Scopus (1) Google Scholar describe the concept of immortal time bias as a possible limitation of our retrospective cohort study evaluating the efficacy of tixagevimab-cilgavimab pre-exposure prophylaxis in solid organ transplant recipients (SOTRs). 2 Al Jurdi A. Morena L. Cote M. Bethea E. Azzi J. Riella L.V. Tixagevimab/cilgavimab pre-exposure prophylaxis is associated with lower breakthrough infection risk in vaccinated solid organ transplant recipients during the Omicron wave. Am J Transplant. 2022; 22: 3130-3136https://doi.org/10.1111/ajt.17128 Abstract Full Text Full Text PDF PubMed Scopus (38) Google Scholar Immortal time bias can occur when study participants cannot experience the outcome during a period of follow-up time (Fig. 1A). A frequently used example is evaluating the efficacy of inhaled glucocorticoids in reducing readmission and death rates after hospitalization for acute exacerbation of chronic obstructive pulmonary disease. 3 Suissa S. Effectiveness of inhaled corticosteroids in chronic obstructive pulmonary disease: immortal time bias in observational studies. Am J Respir Crit Care Med. 2003; 168: 49-53https://doi.org/10.1164/rccm.200210-1231OC Crossref PubMed Scopus (219) Google Scholar If follow-up for the control group is started on the day of discharge and follow-up for the treatment group is started on the day of obtaining the prescription, the time between discharge and obtaining the prescription in the inhaled glucocorticoid group would be classified as immortal time, because an event occurring during that time would not be included in a fixed-time analysis. This is an important concept because it can alter the findings in favor of the intervention group. Tixagevimab/cilgavimab pre-exposure prophylaxis and breakthrough infection risk in vaccinated solid organ transplant recipients: concern for immortal time bias effectAmerican Journal of TransplantationVol. 23Issue 3PreviewWe read with interest the recent Brief Communication from Al Jurdi et al1 describing their experience with COVID-19 breakthrough infection following tixagevimab/cilgavimab (T/C) administration in their vaccinated solid organ transplant recipient population. The main finding was a lower incidence of COVID-19 infection in the group that received T/C, especially among the subgroup of lung transplant and kidney transplant recipients. We would like to add the concept of immortal time bias to the discussion of the limitations in the interpretation of the study results. Full-Text PDF
Institutions: Harvard University, Massachusetts General Hospital
Language: English
Subfield: Infectious Diseases
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $4,300
OpenAlex ID: W4319460539