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Course: Development of COVIDVax Model to Estimate the Risk of SARS-CoV-2–Related Death Among 7.6 Million US Veterans for Use in Vaccination Prioritization

CME Credits: 1.00

Released: 2021-04-06

Key Points

Question How can the risk of SARS-CoV-2–related death be estimated in the general population to be used for vaccination prioritization?
Findings In this prognostic study of more than 7.6 million individuals enrolled in the Veterans Affairs health care system, a logistic regression model (COVIDVax) was developed to estimate risk of SARS-CoV-2–related death using the following 10 characteristics: sex, age, race, ethnicity, body mass index, Charlson Comorbidity Index, diabetes, chronic kidney disease, congestive heart failure, and the Care Assessment Need score. The model was estimated to save more lives than prioritizing vaccination based on age or on the US Centers for Disease Control and Prevention vaccination allocation.
Meaning These findings suggest that prioritizing vaccination based on the model developed in this study could prevent a substantial number of SARS-CoV-2–related deaths during vaccine rollout.

Abstract

Importance A strategy that prioritizes individuals for SARS-CoV-2 vaccination according to their risk of SARS-CoV-2–related mortality would help minimize deaths during vaccine rollout.
Objective To develop a model that estimates the risk of SARS-CoV-2–related mortality among all enrollees of the US Department of Veterans Affairs (VA) health care system.
Design, Setting, and Participants This prognostic study used data from 7,635,064 individuals enrolled in the VA health care system as of May 21, 2020, to develop and internally validate a logistic regression model (COVIDVax) that predicted SARS-CoV-2–related death (n?=-2422) during the observation period (May 21 to November 2, 2020) using baseline characteristics known to be associated with SARS-CoV-2–related mortality, extracted from the VA electronic health records (EHRs). The cohort was split into a training period (May 21 to September 30) and testing period (October 1 to November 2).
Main Outcomes and Measures SARS-CoV-2–related death, defined as death within 30 days of testing positive for SARS-CoV-2. VA EHR data streams were imported on a data integration platform to demonstrate that the model could be executed in real-time to produce dashboards with risk scores for all current VA enrollees.
Results Of 7,635,064 individuals, the mean (SD) age was 66.2 (13.8) years, and most were men (7,051,912 [92.4%]) and White individuals (4,887,338 [64.0%]), with 1,116,435 (14.6%) Black individuals and 399,634 (5.2%) Hispanic individuals. From a starting pool of 16 potential predictors, 10 were included in the final COVIDVax model, as follows: sex, age, race, ethnicity, body mass index, Charlson Comorbidity Index, diabetes, chronic kidney disease, congestive heart failure, and Care Assessment Need score. The model exhibited excellent discrimination with area under the receiver operating characteristic curve (AUROC) of 85.3% (95% CI, 84.6%-86.1%), superior to the AUROC of using age alone to stratify risk (72.6%; 95% CI, 71.6%-73.6%). Assuming vaccination is 90% effective at preventing SARS-CoV-2–related death, using this model to prioritize vaccination was estimated to prevent 63.5% of deaths that would occur by the time 50% of VA enrollees are vaccinated, significantly higher than the estimate for prioritizing vaccination based on age (45.6%) or the US Centers for Disease Control and Prevention phases of vaccine allocation (41.1%).
Conclusions and Relevance In this prognostic study of all VA enrollees, prioritizing vaccination based on the COVIDVax model was estimated to prevent a large proportion of deaths expected to occur during vaccine rollout before sufficient herd immunity is achieved.


Educational Objective
To identify the key insights or developments described in this article


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