BODY FLUID CHARACTERISTICS AND ASSOCIATED FACTORS IN PATIENTS WITH CHRONIC KIDNEY DISEASE STAGES 3–5 NOT YET ON RENAL REPLACEMENT THERAPY

Objectives: To evaluate body fluid characteristics using Bioimpedance Spectroscopy (BIS/BCM) and to identify associated factors in patients with chronic kidney disease (CKD) stages 3–5 not yet on renal replacement therapy. Materials and Methods: A cross-sectional descriptive study was conducted on 413 patients with CKD stages 3–5 undergoing outpatient follow-up at the Center for Nephrology, Urology, and Dialysis at Bach Mai Hospital from November 2025 to April 2026. Fluid status was assessed using the Body Composition Monitor (BCM) device, combined with clinical examination and laboratory tests. Results: The mean age was 56.3 ± 15.98 years; 50.36% were male and 49.64% were female. The prevalence of fluid overload based on the Overhydration (OH) index (>1.1 L) was 16.46% (dehydration: 5.81%, normovolemia: 77.27%). Clinical evaluation identified fluid overload in only 13.1% of patients. Factors associated with fluid overload included male gender (p < 0.05), diabetes mellitus (p < 0.05), advanced CKD stages (stage 4–5), and hypoalbuminemia (<35 g/l) (p < 0.05). The OH index correlated inversely with serum albumin (r = -0.477) and total serum protein (r = -0.323), and positively with the urine protein-to-creatinine ratio (UPCR) (r = 0.334) (p < 0.001). Conclusions: The prevalence of fluid overload detected by BIS/BCM (16.46%) in patients with stage 3–5 CKD is higher than that identified by clinical assessment alone. Associated factors include male gender, diabetes mellitus, liver cirrhosis, disease stage, and hypoalbuminemia. The BCM device serves as an effective tool to support early detection and accurate assessment of fluid status.