Presenter Status

Fellow

Abstract Type

Research

Primary Mentor

Jay Portnoy, MD

Start Date

5-5-2022 11:30 AM

End Date

5-5-2022 1:30 PM

Presentation Type

Poster Presentation

Description

Background: Specific IgE (sIgE) to foods has been used to predict the risk of a systemic reaction (SR) when the food is ingested. An arbitrary cutoff of 0.35 is often used to separate a positive likelihood ratio (LR+) from a negative one (LR-), yet there is little evidence supporting the use of this value.

Objectives/Goal: The objective of this project was to establish a more accurate method for estimating the probability of food allergy to egg.

Methods/Design: Egg-sIgEs were measured and open oral egg challenges were performed on 155 children with a clinical history of egg allergy. Logistic regression (LR) was performed with sIgE as the dependent variable and the result of the egg challenge as the independent variable. A random forest (RF) analysis was also performed on these same data. Receiver operating characteristics (ROC) curves were generated for both LR and RF analyses.

Results: The area under the curve (AUC) for LR was 0.87 and for the RF was 0.77 indicating that LR gave a better model for predicting egg reactions. LRs were determined for each value of sIgE represented on the LR ROC curve. The regression equation for this was LR=0.9641ln(sIgE)+1.4542 with an Rsquared of 0.93. Setting LR to 1 and solving for sIgE gave a cutoff of 0.62kU/L. The usual cutoff of 0.35kU/L gave a LR of 0.44 indicating a decreased likelihood of egg allergy in such patients.

Conclusions: Use of LRs generated from ROC curves provides a method for calculating cutoffs for sIgE tests and for determining LRs for each value of sIgE. When combined with Bayesian analysis, this may lead to a more accurate estimate for the probability of food allergy.

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May 5th, 11:30 AM May 5th, 1:30 PM

Likelihood Ratios for Reactions to Egg based on Specific IgE and Oral Challenges

Background: Specific IgE (sIgE) to foods has been used to predict the risk of a systemic reaction (SR) when the food is ingested. An arbitrary cutoff of 0.35 is often used to separate a positive likelihood ratio (LR+) from a negative one (LR-), yet there is little evidence supporting the use of this value.

Objectives/Goal: The objective of this project was to establish a more accurate method for estimating the probability of food allergy to egg.

Methods/Design: Egg-sIgEs were measured and open oral egg challenges were performed on 155 children with a clinical history of egg allergy. Logistic regression (LR) was performed with sIgE as the dependent variable and the result of the egg challenge as the independent variable. A random forest (RF) analysis was also performed on these same data. Receiver operating characteristics (ROC) curves were generated for both LR and RF analyses.

Results: The area under the curve (AUC) for LR was 0.87 and for the RF was 0.77 indicating that LR gave a better model for predicting egg reactions. LRs were determined for each value of sIgE represented on the LR ROC curve. The regression equation for this was LR=0.9641ln(sIgE)+1.4542 with an Rsquared of 0.93. Setting LR to 1 and solving for sIgE gave a cutoff of 0.62kU/L. The usual cutoff of 0.35kU/L gave a LR of 0.44 indicating a decreased likelihood of egg allergy in such patients.

Conclusions: Use of LRs generated from ROC curves provides a method for calculating cutoffs for sIgE tests and for determining LRs for each value of sIgE. When combined with Bayesian analysis, this may lead to a more accurate estimate for the probability of food allergy.

 

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