Assessment of Subclinical Fluid Overload in Patients with Hypertension on Maintenance Hemodiafiltration

Background: Fluid overload is one of the main mechanisms associated with the presence of hypertension in dialysis patients. Traditional assessment of volume status relies on physical exam (PE) and ultrasonographic evaluation. The aim was to evaluate the prevalence of subclinical fluid overload with Bioelectrical Impedance Analysis (BIA) in patients with hypertension on maintenance hemodiafiltration (HDF) and to determine associated factors. Methods: This cross-sectional study included patients on maintenance HDF with hypertension defined as pre-dialysis blood pressure (BP) ≥140/90 mmHg or post-dialysis BP ≥130/80 mmHg despite being at its clinical dry weight. Volume status was assessed by PE, lung ultrasound, Venous Excess Ultrasound Score (VExUS) and BIA InBody s10. Subclinical volume overload was defined as the presence of edema on BIA despite normal physical examination and ultrasound evaluation. The data were expressed in medians and interquartile ranges (IQR). Results: Of 45 patients on maintenance HDF, 10 meet the inclusion criteria. Median age was 38.5 years [32-58.5], 60% were women. Pre-dialysis BP was 165/84 mmHg [142/77-182/90] and post-dialysis BP was 157/88 mmHg [145/74-167/91]. 40% of the population had subclinical fluid overload due to BIA. Associated factors with subclinical fluid overload were the age and the post-dialysis minimum diameter of the IVC (Table 1). A higher post-dialysis pulse pressure (PP) (95 [93-97.5] vs 74.5 [60-87], p = 0.036) and a lower post-dialysis heart rate (HR) (66 [65-66.5] vs 81 [74-87], p = 0.037) were associated with subclinical volume overload when this was determined by intracellular water. Conclusion: BIA is a tool for assessing volume status which can detect subclinical fluid overload in patients with hypertension on maintenance HDF. Age and post-dialysis minimum diameter of the IVC were associated factors.Comparison of clinical factors in patients with and without subclinical fluid overload