#3121 THE EFFECTIVENESS OF A GLUTEN-FREE DIET IN PATIENTS WITH IGA NEPHROPATHY
Authors: Mantsaeva Mariya , Borisov Alexey 
Published: June 2023

Abstract

Background and Aims
Modern data from the world literature confirm the association of IgA nephropathy (IgAN) and celiac disease. The inclusion of a gluten-free diet (GFD) in the diet has a beneficial effect not only on gastrointestinal symptoms, but also reduces the clinical and laboratory activity of IgAN. The aim of this study was to evaluate the effect of a gluten-free diet on the course of IgAN using general clinical and immunological tests 6 months after the start of its use.

Method
65 patients with morphologically confirmed IgAN were included in the study. To detect a violation of gluten metabolism, screening determination of the level of IgA antibodies to tissue transglutaminase (Anti-TTG IgA) and IgA antibodies to deamidated gliadin peptides (Anti-DPG IgA) was performed. According to the results of the screening examination, a group of patients with the level of antibodies exceeding the reference values were formed (group 1, n = 13) and a group of patients in whose blood did not exceed the reference values, or were absent at all (group 2, n = 52). Patients of both groups were recommended GFD for a period of at least 6 months. The effectiveness of GFD was evaluated by the following indicators: protein in urine (g/l); red blood cells in urine (RBCs) (hpf); daily proteinuria (g/day); blood creatinine (mmol/l), GFR calculated by the formula CKD-EPI (ml/min /1.73 m2) at the beginning of the study and 6 months after the inclusion of dietary recommendations. Statistical analysis of the data obtained was carried out using the statistical program SPSS Statistics 26.0 (IBM, USA). When comparing quantitative indicators, the distribution of which differed from normal in two related groups, the Wilcoxon criterion was used. The null statistical hypothesis about the absence of differences and connections was rejected at p&lt;0.05.

Results
among the examined patients there were 61 men (93.8%), 4 women (6.2%). The average age of men was 39.0±8.2 years, women - 34.7±9.7 years. The duration of the underlying disease at the time of inclusion in the study was 55.98 [40.67-71.28] months. 57 people (85.1%) received ACE inhibitors/sartans in therapeutic doses as the main therapy, 8 people (11.9%) did not receive drug therapy. It was possible to evaluate the effectiveness of GFD in patients from group 1 in 9 people. During the follow-up period, 2 patients from group 1 showed progression of the disease to the End-Stage Renal Disease (GFR according to CKD-EPI &lt;15 ml/min/1.73 m2), which required their exclusion from the study, in 2 more patients it was not possible to evaluate the effectiveness of GFD due to insufficient follow-up periods (less than 6 months.) GFD was also recommended to patients from group 2. Dietary restrictions were applied to patients with daily protein loss &gt; 0.5 g/day and/or anti-TTG IgA and anti-DPG IgA levels in the range of pre-reference values, thus it was possible to evaluate the effectiveness of GFD in patients of group 2 in 21 people. According to the results of the analysis, a statistically significant decrease in daily proteinuria (p = 0.028) and microscopic hematuria (p = 0.018) was revealed. After 6 months from the start of compliance with GFD, daily proteinuria decreased in 66.7%; microscopic hematuria – in 77.8% in group 1 patients. Among group 2 patients, a statistically significant decrease in microscopic hematuria (p = 0.05) was observed in 76.2% of those included in the study.

Conclusion
the inclusion of GFD in the diet of patients with IgAN is justified in patients with the presence of gluten antibodies in the blood serum, as it allows to significantly reduce the severity of proteinuria, microscopic hematuria in these patients. Screening examination of patients with IgAN for gluten metabolism disorders will expand therapeutic possibilities, and GFD can become part of a nephroprotective strategy.