#6093 CLINICAL UTILITY AND LIMITATIONS OF BIOELECTRICAL IMPEDANCE ANALYSIS FOR ESTIMATING BODY COMPOSITION AND WATER DISTRIBUTION IN ADPKD PATIENTS
Authors: Catania Martina , Vergani Maria Vittoria , Pisoni Matteo Brambilla , Carrera Paola , Vespa Marta , Joli Giancarlo , Bucci Romina , De Rosa Liliana , Paolisi Michele , Bianca Pierpaolo , Mancassola Giulia , Rivera Rodolfo , Vezzoli Giuseppe , Manunta Paolo , Alibrandi Maria Teresa Sciarrone 
Published: June 2023

Abstract

Background and Aims
Autosomal Dominant Polycystic Kidney Disease (ADPKD) is the most common genetic cause leading to end stage renal disease (ESRD). The most striking ADPKD feature, which is the growth of renal cysts leading to nephromegaly and renal function loss, is attributed to the loss of PKD1 and PKD2 genes coding respectively for Polycystin 1 and Polycystin 2, which are proteins located on the primary cilium. ADPKD is considered a systemic disease as several extra-renal manifestations including liver cysts and hepatomegaly, valvular heart disease, aneurysms and diverticulosis can be associated to it. Because of the remarkable renal and hepatic involvement, patients affected by organomegaly may suffer from pressure-related conditions like malnutrition. Nutritional and hydration status can be assessed through Biolectrical Impedance Analysis (BIA), used both in the healthy population and in patients affected by chronic kidney disease (CKD). It is nowadays still not clear whether the presence of renal and hepatic cysts may exert an influence on raw BIA measurements and consequently if this represents an accurate tool to assess nutritional and hydration status in patients affected by ADPKD. Hence, this study was carried out in order to evaluate BIA efficacy and limitations in the ADPKD population.

Methods
We enrolled 132 adult patients (&gt;18 years of age), 71 being affected by ADPKD, 33 being affected by non-ADPKD related CKD and 28 healthy controls. Each patient accepted to undergo BIA analysis and anthropometric measurements (height, weight, BMI), which were performed on the same day. We, then, classified ADPKD patients according to their residual renal function degree and compared them to the corresponding non-ADPKD of the same grade of renal insufficiency.

Results
We observed that in ADPKD patients showing organomegaly, in particular hepatomegaly, there is a positive correlation between this factor and BIA parameters including TBW%, ECW% and ICW%. On the other hand, no significant correlation with age and GFR was found. As far as PhA concerned, which is an indicator of malnutrition both in healthy and ADPKD patients, we observed that it is independent of ADPKD and mostly correlated with age. It has also been demonstrated that PhA significantly decreases in presence of organomegaly or when renal diameters are increased, even in subjects with a preserved or mildly reduced eGFR.

Conclusion
The results of our study are concordant with the only one present in the literature. Phase angle (PhA) has shown to be an important index for malnutrition in patients affected by chronic kidney disease (CKD) secondary to ADPKD or not. Together with other values derived from BIA evaluation, this could be used in the future in order to guide the therapeutic choice even in patients with a preserved renal function or a mildly reduced one.