Objective: A standardised diagnostic definition of protein-losing enteropathy (PLE) in Fontan patients serves both patient care and research. The present study determined whether a diagnostic definition of PLE was routinely used in published clinical Fontan studies, and to identify potentially relevant diagnostic criteria for composing a uniform PLE definition.
Methods: A systematic review was conducted in adherence to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) recommendations. Published clinical Fontan studies that were written in English and included at least four patients with PLE were selected. PLE definitions were quantitatively analysed using a lateral thinking tool in which definitions were fractionated into constituent pieces of information (building blocks or diagnostic criteria).
Results: We identified 364 papers. In the final analysis, data from 62 published articles were extracted. A diagnostic definition of PLE was used in only 27/62 (43.5%) of selected studies, and definitions were very heterogeneous. We identified eight major diagnostic criteria. Hypoalbuminaemia (n=23 studies, 85.2%), clinical presentation (n=18, 66.7%), documentation of enteric protein loss (n=16, 59.3%) and exclusion of other causes of hypoproteinaemia (n=17, 63.0%), were the most frequently used diagnostic criteria. Most studies used three diagnostic variables (n=13/27, 48.1%). Cut-off values for laboratory parameters (serum albumin, protein or faecal α-1-antitrypsin) were frequently incorporated in the PLE definition (n=16, 59.3%).
Conclusions: Establishment of a universally accepted PLE definition for routine use in clinical research and daily practice is required. The diagnostic criteria may help constitute a diagnostic PLE definition.
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