Defense Date

2010

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Pharmacotherapy and Outcomes Science

First Advisor

David Holdford

Abstract

Background: Food allergy, an abnormal immunologic response to food protein, has an estimated prevalence of 6% in young children and 3.7% in adults in the U.S. The only proven therapy for food allergy is strict elimination of the offending allergens. As a result, caregivers and patients could experience constant anxiety and stress that affects their quality of life. Additionally, food allergy can lead to significant economic impact on the health care system, since severe reactions often lead to ED visits and hospitalizations. Objectives: The first major objective was to determine the economic burden of Food Allergy and Anaphylaxis (FAA) patients in the U.S. by estimating the direct medical and indirect costs. The second principal objective involved assessing the Health Related Quality of Life (HRQL) of food allergic patients by measuring their health utilities and disease specific quality of life. Methods: Economic burden was estimated by measuring certain direct medical and indirect costs from a societal perspective. Costs were estimated using a bottom-up approach -- calculating the average cost of illness per patient and multiplying it by reported prevalence estimates. FAA patients with an emergency department (ED) visit, office based physician visit, outpatient department visit, and hospital admission were identified from a list of federally administered databases using ICD-9 codes. Sensitivity analyses were conducted to measure the robustness of the estimates. The cross-sectional HRQL study measured health utilities in food allergic adults and children, and quality of life in allergic adults using EQ-5D and FAQL-AF questionnaires respectively. These questionnaires were administered in an online survey format. Regression models were specified to explore the deviations in HRQL scores between patients with different disease related characteristics. Results: The findings reveal that for a given year (2007), direct medical costs worth $225 million and indirect costs worth $115 million were incurred. Owing to the irregularities in the reporting and diagnosis of food allergy, these values might be an underestimation. Simulations from probabilistic sensitivity analysis generated mean direct medical costs of $307 million and indirect costs of $203 million. Survey responses were collected online for eight months, during which 45 adults and 94 parents (acting as proxy for their food allergic child) responded. Adults reported a mean utility of 0.874 compared to 0.918 for children. Gender, number of food allergies and frequency of carrying epinephrine device had significant impacts on HRQL scores. An effect size of 0.003 was estimated comparing health utilities of food allergic adults with the general U.S. population. Conclusions: This was the first research to examine economic burden of FAA, and elucidate health utilities for food allergic patients. A large proportion of costs were incurred due to ambulatory visits. Effect size calculation revealed that health utilities of food allergic patients were very similar to the general U.S. population.

Rights

© The Author

Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

August 2010

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