Introduction
The burden of food allergy (FA) remains a significant public health
concern. There is ample evidence for the negative impact that FA can
have on the quality of life of patients and their families, on the
breadth and quality of social interactions, on the performance at school
or work and on overall psychological well-being [1-3]. This is
aggravated by the financial strain that FAs impose on families and
individuals through the cost of allergen-free food, direct and indirect
medical expenses, and missed work or school days [4].
A recently published study documents a continued increase in the
prevalence of FA in Europe. It estimates lifetime and point prevalence
of self-reported FA to be 20% and 13%, respectively [5].
Considering both a clinical diagnosis of food allergy or a positive OFC,
FAs have increased from 2.6% in the early 2000’s to 3.5% in the next
decade [5]. Currently, FA confirmed by oral food challenge (OFC)
worldwide is estimated at 4%[6]. This has resulted in a growing
demand for appropriate FA diagnosis, driving health care professionals
to employ a wide range of allergy tests. However, not all these
diagnostic tests are equally useful or appropriate to reach an accurate
diagnosis of FA and while the OFC remains the reference standard, it is
a costly and time-consuming procedure that may lead to life-threatening
anaphylaxis [7]. For a highly sensitive test, a negative result
effectively rules out the diagnosis of FA; for a highly specific test, a
positive result rules in a FA diagnosis. Deeper understanding of
diagnostic test accuracy could reduce the need for OFC and guide
clinical practice.
Determining the optimal diagnostic cut-offs in single studies that are
generalisable to other clinical settings poses a significant challenge.
By combining and analysing data from multiple studies, we can overcome
the limitations of individual studies and gain a more comprehensive
understanding of the diagnostic performance of tests. Meta-analyses
allow us to synthesize findings from various sources, enhancing the
reliability and generalizability of the results. Thus, they play a
crucial role in guiding clinical decision-making and improving
diagnostic accuracy.
The European Academy of Allergy and Clinical Immunology (EAACI) is
updating their guidelines on both the diagnosis and management of FA
[8, 9]. A systematic review (SR) of index tests is the most reliable
form of evidence in the diagnostic field and enables clinicians and
other healthcare professionals to make well-informed decisions [10,
11]. To inform the EAACI guidelines on FA diagnosis, we undertook a SR
and meta-analysis (meta-analyses) about the accuracy of index tests to
support the diagnosis of IgE-mediated FA, following a previously
registered and published protocol [12].
This SR addresses the question: What is the diagnostic accuracy measured
by the sensitivity and specificity of any index test for IgE-mediated FA
to any food compared with the reference standard OFC (in at least a
subset of patients) or previous clear history of immediate reaction to
the food and evidence of IgE sensitisation?